Homebrew_PCBs

> I searched but weren't able to locate any posts on the subject but

> recall that tehre was a dicussion of it. Does anyone know a simple
> method that works on plating holes in a PCB? Mike

----- Original Message -----
From: Dave Mucha
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, July 29, 2004 1:31 AM
Subject: [Homebrew_PCBs] Re: Plating thruholes.


--- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...> wrote:
> I searched but weren't able to locate any posts on the subject but
I
> recall that tehre was a dicussion of it. Does anyone know a simple
> method that works on plating holes in a PCB? Mike



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[Non-text portions of this message have been removed]

> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>

> > I searched but weren't able to locate any posts on the subject

> I
> > recall that tehre was a dicussion of it. Does anyone know a

> > method that works on plating holes in a PCB? Mike
>
> I think the best home-brew (closer to professional sho) unit is

> Markus
>
> http://www.myhome.ch/mzingg/pcbstuff/tps/
>
>
> Also go back to the posts around 1100, maybe go directly to 1108

> start reading. IIRC, there was a detailed list of each step

>
> This is not for the faint of heart nor a simple one shot project.
>
>
> On the other side of things, there is a simple method from think

> tinker that plates the holes with a silver compound. not cheap.
>
> And there has been some mention of using carbon black as a method.
> look around message 170.
>
> also post 1163 and 2344
>
> Interestlingly there is not a lot of posts regarding this. I would
> have hoped someone would have figured out how to do it easier.
>
>
> IIRC, there was a gentleman who posted quite a bit about carbon

> and his findings about using that to create the connections.
>
> Most of use try to use single sided boards to the greatest level

> then add as few jumpers as possible. As Stefan pointed out

> a resistor is a zero hole connection. so, if you can, use your

> hole devices as ways to connect both sides of the boards.
>
> And if you find you are doing a lot near an IC, you can take a
> machined pin IC socket and pull out all the pins and press them

> the holes on the board and then solder from both sides.
>
> Dave

>Excellent info, Dave. I wish Marcus provided email to ocntact him.
>
>Mike
>
>--- In Homebrew_PCBs@yahoogroups.com, "Dave Mucha" <dave_mucha@y...>
>wrote:
>> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>
>wrote:
>> > I searched but weren't able to locate any posts on the subject
>but
>> I
>> > recall that tehre was a dicussion of it. Does anyone know a
>simple
>> > method that works on plating holes in a PCB? Mike
>>
>> I think the best home-brew (closer to professional sho) unit is
>from
>> Markus
>>
>> http://www.myhome.ch/mzingg/pcbstuff/tps/
>>
>>
>> Also go back to the posts around 1100, maybe go directly to 1108
>and
>> start reading. IIRC, there was a detailed list of each step
>needed.
>>
>> This is not for the faint of heart nor a simple one shot project.
>>
>>
>> On the other side of things, there is a simple method from think
>and
>> tinker that plates the holes with a silver compound. not cheap.
>>
>> And there has been some mention of using carbon black as a method.
>> look around message 170.
>>
>> also post 1163 and 2344
>>
>> Interestlingly there is not a lot of posts regarding this. I would
>> have hoped someone would have figured out how to do it easier.
>>
>>
>> IIRC, there was a gentleman who posted quite a bit about carbon
>black
>> and his findings about using that to create the connections.
>>
>> Most of use try to use single sided boards to the greatest level
>and
>> then add as few jumpers as possible. As Stefan pointed out
>recently,
>> a resistor is a zero hole connection. so, if you can, use your
>thru-
>> hole devices as ways to connect both sides of the boards.
>>
>> And if you find you are doing a lot near an IC, you can take a
>> machined pin IC socket and pull out all the pins and press them
>into
>> the holes on the board and then solder from both sides.
>>
>> Dave
>
>
>
>
>Be sure to visit the group home and check for new Bookmarks and files:
>http://groups.yahoo.com/group/Homebrew_PCBs
>Yahoo! Groups Links
>
>
>
>

>
>
> m.zingg@n...
>
> No problem
>
> Markus
>
> >Excellent info, Dave. I wish Marcus provided email to ocntact him.
> >
> >Mike
> >
> >--- In Homebrew_PCBs@yahoogroups.com, "Dave Mucha"

> >wrote:
> >> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>
> >wrote:
> >> > I searched but weren't able to locate any posts on the subject
> >but
> >> I
> >> > recall that tehre was a dicussion of it. Does anyone know a
> >simple
> >> > method that works on plating holes in a PCB? Mike
> >>
> >> I think the best home-brew (closer to professional sho) unit is
> >from
> >> Markus
> >>
> >> http://www.myhome.ch/mzingg/pcbstuff/tps/
> >>
> >>
> >> Also go back to the posts around 1100, maybe go directly to 1108
> >and
> >> start reading. IIRC, there was a detailed list of each step
> >needed.
> >>
> >> This is not for the faint of heart nor a simple one shot project.
> >>
> >>
> >> On the other side of things, there is a simple method from think
> >and
> >> tinker that plates the holes with a silver compound. not cheap.
> >>
> >> And there has been some mention of using carbon black as a

> >> look around message 170.
> >>
> >> also post 1163 and 2344
> >>
> >> Interestlingly there is not a lot of posts regarding this. I

> >> have hoped someone would have figured out how to do it easier.
> >>
> >>
> >> IIRC, there was a gentleman who posted quite a bit about carbon
> >black
> >> and his findings about using that to create the connections.
> >>
> >> Most of use try to use single sided boards to the greatest level
> >and
> >> then add as few jumpers as possible. As Stefan pointed out
> >recently,
> >> a resistor is a zero hole connection. so, if you can, use your
> >thru-
> >> hole devices as ways to connect both sides of the boards.
> >>
> >> And if you find you are doing a lot near an IC, you can take a
> >> machined pin IC socket and pull out all the pins and press them
> >into
> >> the holes on the board and then solder from both sides.
> >>
> >> Dave
> >
> >
> >
> >
> >Be sure to visit the group home and check for new Bookmarks and

> >http://groups.yahoo.com/group/Homebrew_PCBs
> >Yahoo! Groups Links
> >
> >
> >
> >

> I can't believe- Markus is a member of this board! It is a very
> professionally looking setup that you created.
>
> Have you been able to provide few words that people could follow your
> idea of plating thru?
>
> Picture with two copper plates and a airating tube in between: how
> are the plates connected to the PS? Both are conencted to each other
> and then they are connected to + and - ?!?!
>
> Mike
>

> I can't believe- Markus is a member of this board! It is a very
> professionally looking setup that you created.

----- Original Message -----
From: Dave Mucha
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, July 29, 2004 11:53 AM
Subject: [Homebrew_PCBs] Re: Plating thruholes.


--- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...> wrote:
> I can't believe- Markus is a member of this board! It is a very
> professionally looking setup that you created.


That is what I was trying to say to Ballendo. the 'brain trust' on
this board peaks in the 'making PCB's area and is THE place to get
ansers when you want to make PCB's.

And yes, Markus holds the bar very high for the rest of us !
I just wish he were close by my area.

There is a NJ robotics society and one of the guys and a laser board
etcher. about 4 ft cube. Wanna talk about envy ? Problem for me is
that he is too far away....

Oh, may I respectfully request that you keep your questions on the
open list and not in personal e-mails? the rest of us would like to
listen in.


Dave






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[Non-text portions of this message have been removed]

> While I'll admit Markus's plating system is a piece of working art,

> In my tank, the anodes (4X6) are not as big as the pcb(6X9), and

>
> The kit from Caswell includes 2 buckets, heater, anodes, cleaning

>
> JT
> http://www.soundclick.com/jtsound
> ----- Original Message -----
> From: Dave Mucha
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Thursday, July 29, 2004 11:53 AM
> Subject: [Homebrew_PCBs] Re: Plating thruholes.
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>

> > I can't believe- Markus is a member of this board! It is a very
> > professionally looking setup that you created.
>
>
> That is what I was trying to say to Ballendo. the 'brain trust'

> this board peaks in the 'making PCB's area and is THE place to

> ansers when you want to make PCB's.
>
> And yes, Markus holds the bar very high for the rest of us !
> I just wish he were close by my area.
>
> There is a NJ robotics society and one of the guys and a laser

> etcher. about 4 ft cube. Wanna talk about envy ? Problem for

> that he is too far away....
>
> Oh, may I respectfully request that you keep your questions on

> open list and not in personal e-mails? the rest of us would like

> listen in.
>
>
> Dave
>
>
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and

> http://groups.yahoo.com/group/Homebrew_PCBs
>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
>
>
>
> --------------------------------------------------------------------

> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
> http://groups.yahoo.com/group/Homebrew_PCBs/
>
> b.. To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
> c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of

>
>
>
> [Non-text portions of this message have been removed]

> While I'll admit Markus's plating system is a piece of working art,

> In my tank, the anodes (4X6) are not as big as the pcb(6X9), and

>
> The kit from Caswell includes 2 buckets, heater, anodes, cleaning

>
> JT
> http://www.soundclick.com/jtsound
> ----- Original Message -----
> From: Dave Mucha
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Thursday, July 29, 2004 11:53 AM
> Subject: [Homebrew_PCBs] Re: Plating thruholes.
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>

> > I can't believe- Markus is a member of this board! It is a very
> > professionally looking setup that you created.
>
>
> That is what I was trying to say to Ballendo. the 'brain trust'

> this board peaks in the 'making PCB's area and is THE place to

> ansers when you want to make PCB's.
>
> And yes, Markus holds the bar very high for the rest of us !
> I just wish he were close by my area.
>
> There is a NJ robotics society and one of the guys and a laser

> etcher. about 4 ft cube. Wanna talk about envy ? Problem for

> that he is too far away....
>
> Oh, may I respectfully request that you keep your questions on

> open list and not in personal e-mails? the rest of us would like

> listen in.
>
>
> Dave
>
>
>
>
>
>
> Be sure to visit the group home and check for new Bookmarks and

> http://groups.yahoo.com/group/Homebrew_PCBs
>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
>
>
>
> --------------------------------------------------------------------

> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
> http://groups.yahoo.com/group/Homebrew_PCBs/
>
> b.. To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
> c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of

>
>
>
> [Non-text portions of this message have been removed]

----- Original Message -----
From: mikezcnc
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, July 29, 2004 4:10 PM
Subject: [Homebrew_PCBs] Re: Plating thruholes.


Jeremy, would you suggest
http://www.caswellplating.com/kits/copper.htm or this
http://www.caswellplating.com/kits/flashcopper.html Mike



[Non-text portions of this message have been removed]

> I have used both.
> I prefer Flash copper but either will work well.
> JT
>
> ----- Original Message -----
> From: mikezcnc
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Thursday, July 29, 2004 4:10 PM
> Subject: [Homebrew_PCBs] Re: Plating thruholes.
>
>
> Jeremy, would you suggest
> http://www.caswellplating.com/kits/copper.htm or this
> http://www.caswellplating.com/kits/flashcopper.html Mike
>
>
>
> [Non-text portions of this message have been removed]

> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...> wrote:
>
>>I searched but weren't able to locate any posts on the subject but
>
> I
>
>>recall that tehre was a dicussion of it. Does anyone know a simple
>>method that works on plating holes in a PCB? Mike
>
>
> I think the best home-brew (closer to professional sho) unit is from
> Markus
>
> http://www.myhome.ch/mzingg/pcbstuff/tps/
>
>
> Also go back to the posts around 1100, maybe go directly to 1108 and
> start reading. IIRC, there was a detailed list of each step needed.
>
> This is not for the faint of heart nor a simple one shot project.

----- Original Message -----
From: Adam Seychell
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, July 29, 2004 9:05 PM
Subject: Re: [Homebrew_PCBs] Re: Plating thruholes.


Dave Mucha wrote:
> --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...> wrote:
>
>>I searched but weren't able to locate any posts on the subject but
>
> I
>
>>recall that tehre was a dicussion of it. Does anyone know a simple
>>method that works on plating holes in a PCB? Mike
>
>
> I think the best home-brew (closer to professional sho) unit is from
> Markus
>
> http://www.myhome.ch/mzingg/pcbstuff/tps/
>
>
> Also go back to the posts around 1100, maybe go directly to 1108 and
> start reading. IIRC, there was a detailed list of each step needed.
>
> This is not for the faint of heart nor a simple one shot project.

This is very true. The electroplating, and application of your own
photoresists is the other major parts of the PTH process.

In addition to etching, and photo imaging, you must;

1) cleaning PCB surface to prepare for electroplating.
2) ability to apply your own dry film photoresist
3) give holes the ability to plate.
4) setup acid copper electroplating tank with proprietary additives.

There are several methods of doing (3), such as with carbon dispersion,
electroless copper solutions, or with palladium colloid solutions. I
believe Markus's setup is using the palladium colloid solutions. All
three processes have their problems, and I would say the most critical
step in the process.

Let me know if you have any questions.

Adam


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[Non-text portions of this message have been removed]

> Adam
> Flash copper (Alkaline) works better for me than acid copper. In

>
> A quick dip in HOT tsp (tri sodium phosphate) does a great job of

>
> JT
>
> ----- Original Message -----
> From: Adam Seychell
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Thursday, July 29, 2004 9:05 PM
> Subject: Re: [Homebrew_PCBs] Re: Plating thruholes.
>
>
> Dave Mucha wrote:
> > --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>

> >
> >>I searched but weren't able to locate any posts on the subject

> >
> > I
> >
> >>recall that tehre was a dicussion of it. Does anyone know a

> >>method that works on plating holes in a PCB? Mike
> >
> >
> > I think the best home-brew (closer to professional sho) unit is

> > Markus
> >
> > http://www.myhome.ch/mzingg/pcbstuff/tps/
> >
> >
> > Also go back to the posts around 1100, maybe go directly to

> > start reading. IIRC, there was a detailed list of each step

> >
> > This is not for the faint of heart nor a simple one shot

>
> This is very true. The electroplating, and application of your

> photoresists is the other major parts of the PTH process.
>
> In addition to etching, and photo imaging, you must;
>
> 1) cleaning PCB surface to prepare for electroplating.
> 2) ability to apply your own dry film photoresist
> 3) give holes the ability to plate.
> 4) setup acid copper electroplating tank with proprietary

>
> There are several methods of doing (3), such as with carbon

> electroless copper solutions, or with palladium colloid

> believe Markus's setup is using the palladium colloid solutions.

> three processes have their problems, and I would say the most

> step in the process.
>
> Let me know if you have any questions.
>
> Adam
>
>
> Be sure to visit the group home and check for new Bookmarks and

> http://groups.yahoo.com/group/Homebrew_PCBs
>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
>
>
>
> --------------------------------------------------------------------

> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
> http://groups.yahoo.com/group/Homebrew_PCBs/
>
> b.. To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
> c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of

>
>
>
> [Non-text portions of this message have been removed]

> > This is not for the faint of heart nor a simple one shot project.
>
> This is very true. The electroplating, and application of your own
> photoresists is the other major parts of the PTH process.
>
> In addition to etching, and photo imaging, you must;
>
> 1) cleaning PCB surface to prepare for electroplating.
> 2) ability to apply your own dry film photoresist
> 3) give holes the ability to plate.
> 4) setup acid copper electroplating tank with proprietary additives.
>
> There are several methods of doing (3), such as with carbon

> electroless copper solutions, or with palladium colloid

> believe Markus's setup is using the palladium colloid solutions.

> three processes have their problems, and I would say the most

> step in the process.
>
> Let me know if you have any questions.
>
> Adam

>Jeremy,
>
>1. Where do you buy TSP?

----- Original Message -----
From: mikezcnc
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, July 29, 2004 11:05 PM
Subject: [Homebrew_PCBs] Re: Plating thruholes.


Jeremy,

1. Where do you buy TSP? I chceked and it is some kind of a cleaner.
Sounds like a great suggestion. I searched this board and it wasn't
mentioned before.

2. What do you use for 'activating' the holes, to make the conductive
so the copper can be later deposited electrochemically?

3. For the others benefit, I am adding this link according to
Jeremy's suggestion:

http://www.caswellplating.com/kits/flashcopper.html

Once Jeremy tells us what to use to make the holes conductive, we
have all crucial details to make plated holes in a homebrew manner,
right?

Mike


--- In Homebrew_PCBs@yahoogroups.com, "Jeremy Taylor" <jeremy@e...>
wrote:
> Adam
> Flash copper (Alkaline) works better for me than acid copper. In
the future you might just want to say "copper plating" leaving "acid"
out as there is more than one way to plate copper.
>
> A quick dip in HOT tsp (tri sodium phosphate) does a great job of
pre-plate - pre lamination cleaning, and I suspect it would also work
well for tt (no sandpaper needed)
>
> JT
>
> ----- Original Message -----
> From: Adam Seychell
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Thursday, July 29, 2004 9:05 PM
> Subject: Re: [Homebrew_PCBs] Re: Plating thruholes.
>
>
> Dave Mucha wrote:
> > --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...>
wrote:
> >
> >>I searched but weren't able to locate any posts on the subject
but
> >
> > I
> >
> >>recall that tehre was a dicussion of it. Does anyone know a
simple
> >>method that works on plating holes in a PCB? Mike
> >
> >
> > I think the best home-brew (closer to professional sho) unit is
from
> > Markus
> >
> > http://www.myhome.ch/mzingg/pcbstuff/tps/
> >
> >
> > Also go back to the posts around 1100, maybe go directly to
1108 and
> > start reading. IIRC, there was a detailed list of each step
needed.
> >
> > This is not for the faint of heart nor a simple one shot
project.
>
> This is very true. The electroplating, and application of your
own
> photoresists is the other major parts of the PTH process.
>
> In addition to etching, and photo imaging, you must;
>
> 1) cleaning PCB surface to prepare for electroplating.
> 2) ability to apply your own dry film photoresist
> 3) give holes the ability to plate.
> 4) setup acid copper electroplating tank with proprietary
additives.
>
> There are several methods of doing (3), such as with carbon
dispersion,
> electroless copper solutions, or with palladium colloid
solutions. I
> believe Markus's setup is using the palladium colloid solutions.
All
> three processes have their problems, and I would say the most
critical
> step in the process.
>
> Let me know if you have any questions.
>
> Adam
>
>
> Be sure to visit the group home and check for new Bookmarks and
files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
>
>
>
> --------------------------------------------------------------------
----------
> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
> http://groups.yahoo.com/group/Homebrew_PCBs/
>
> b.. To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
> c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of
Service.
>
>
>
> [Non-text portions of this message have been removed]



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------------------------------------------------------------------------------
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c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



[Non-text portions of this message have been removed]

>>>This is not for the faint of heart nor a simple one shot project.
>>
>>This is very true. The electroplating, and application of your own
>>photoresists is the other major parts of the PTH process.
>>
>>In addition to etching, and photo imaging, you must;
>>
>>1) cleaning PCB surface to prepare for electroplating.
>>2) ability to apply your own dry film photoresist
>>3) give holes the ability to plate.
>>4) setup acid copper electroplating tank with proprietary additives.
>>
>>There are several methods of doing (3), such as with carbon
>
> dispersion,
>
>> electroless copper solutions, or with palladium colloid
>
> solutions. I
>
>>believe Markus's setup is using the palladium colloid solutions.
>
> All
>
>>three processes have their problems, and I would say the most
>
> critical
>
>>step in the process.
>>
>>Let me know if you have any questions.
>>
>>Adam
>
>
> I think we have all been looking for a simple way to plate thru-holes.
>
> I know that when I run into this problem, I try to use a resistor or
> some other thru hole part as the connection and then solder both
> sides.
>
> Since most of use use boards that are less than about 6" x 6" the
> size of a tank should not be terribly large.
>
> Any ideas on a a simple way to do plating
>
> Dave

--- In Homebrew_PCBs@yahoogroups.com, JanRwl@A... wrote:
> In a message dated 7/29/2004 10:23:09 PM Central Standard Time,
> dave_mucha@y... writes:
> Any ideas on a a simple way to do plating
> Dave: Even IF PTH was no more hassle than etching a single-sided
board, if
> one DOES PTH the drilled blank successfully/adequately, THEN the
ONLY way to
> apply "resist" is to TIN-PLATE the desired pattern using
a "negative" image of
> "plating resist" which exposes only the desired tracks and
the "insides" of the
> holes, of course. Then the tin plating resists the ammonium
persulfate etch.
>
>
> Sad, but MUCH more involved than basic double-sided copper boards!
I tried
> the "electroless tin-plate" one firm (Kepro???) once offered, and
it worked,
> but NOT very well, and required pre-heating of the liquid, and it
PRECLUDED the
> use of "kitchen utensils" as many of us do, AND, even if done a
VERY long
> time, the resulting plating was NOT totally "chemically opaque", so
pin-holes
> would result during etching, etc., etc. Though boards plated with
this
> electroless tin stuff DID look much better than corroded ol' brown
copper! So I now
> have any of MY boards done professionally, if I need ten or more of
same board,
> or gold fingers, and just "solder both sides" of lead-wires for
those holes
> that MUST "go through", or I use eyelets where absolutely
necessary. A pain,
> yes, and not as "neat" as PTH, but what can we do? PUNT!
>
> Jan Rowland
>
>
> [Non-text portions of this message have been removed]

> Jan,
>
> Just a word of comment: I tried the electroless tin and it workd
> exceptionally well on tinning the PCBs. I was quite amazed how well
> it work, exactly in a kitchen and I keep in tee fridge all the time.
> Life of the solution according to a mfr is six months and the cost is
> low for that amount of time.
>
> However, I don't know what the electroless tin does to a hole- that I
> hvent tested but I suspect that unless the hole is copper, than
> nothing.
>
> It wasn't clear from your post if you were talking about tinning the
> copper traces or tinning the thruholes. For traces to be tinned, the
> solution needs to be hot, otherwise it takes very long time. Mike
>
>

> On Fri, 30 Jul 2004 11:12:19 -0000, mikezcnc <eemikez@c...> wrote:
>
> > Jan,
> >
> > Just a word of comment: I tried the electroless tin and it workd
> > exceptionally well on tinning the PCBs. I was quite amazed how

> > it work, exactly in a kitchen and I keep in tee fridge all the

> > Life of the solution according to a mfr is six months and the

> > low for that amount of time.
> >
> > However, I don't know what the electroless tin does to a hole-

> > hvent tested but I suspect that unless the hole is copper, than
> > nothing.
> >
> > It wasn't clear from your post if you were talking about tinning

> > copper traces or tinning the thruholes. For traces to be tinned,

> > solution needs to be hot, otherwise it takes very long time. Mike
> >
> >
>
> The last time i checked all electroless tin used some pretty nasty
> ingredients
> which i wouldn't want to have in the kitchen or fridge.
> What about yours?
>
> ST

> Stefan,
>
> I would like three issues answered by a chemist and or pharmacist
> (although here I suspect that argument would be made that since it is
> used for rubbing then it must be ok:
>
> 1. The web search reveals that IPA causes cancer.

> We might get into
> semantics on that one,

> but we should not use an argument of rubbing
> alcohol being healthy, therfeore and the reason being that that
> discussion might turn in to medical subject which I won't get into. I
> know it is carcinogennic and if someone believes otherwise, I can
> respect that.

>
> 2. Tinnit says: it contains "acidic tin salts, although it
> doesn'tcyanide or other highly poisonous materials it is a skin and
> eye irritant- do not eat or drink". I realize that keeping it in the
> fridge is not for anybody else than me. Fridge is for food only, but
> since it is my fridge then I issued yself a waver from that otherwise
> strict regulation. Now, Stefan, aside how bad that stuff is to our
> helth, you made me think that if it works on copper traces, will 'go
> into the holes'? I would say it will go into the holes ONLY if the
> holes are copper plated.... But for that is the method of using H2S04
> and CuSO4 with DC current or like Jeremy suggested (better yet)
> use 'flash copper' rather than acidic copper... Tinning with that
> stuff brings awsome results, but there are some rather smallish fumes.

>
> 3. I would like a chemist to tell us how does IPA clean, because it
> does not dissolve oils nor fats. And if it doesn't then what kind of
> principle is applied for cleaning with it?

> I've already told you all, several times. I use the Think and

> Otherwise, Ron at think and tinker has done a very good job - and

> These links area already in the links section of this well

>
> To put it bluntly - there is no FREE way to do this. You can either

>
> For those of us doing PTH - I'm curious what your setup cost was?.
> Not including imaging, etching , drilling, etc..
> Just the PTH plating setup - for me I figure about $700 for ink,

> My plating systems are built in to the same table top as my

>
> TSP is found at your average hardware store. - I think the key for

> JT
>
>
> ----- Original Message -----
> From: mikezcnc
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Thursday, July 29, 2004 11:05 PM
> Subject: [Homebrew_PCBs] Re: Plating thruholes.
>
>
> Jeremy,
>
> 1. Where do you buy TSP? I chceked and it is some kind of a

> Sounds like a great suggestion. I searched this board and it

> mentioned before.
>
> 2. What do you use for 'activating' the holes, to make the

> so the copper can be later deposited electrochemically?
>
> 3. For the others benefit, I am adding this link according to
> Jeremy's suggestion:
>
> http://www.caswellplating.com/kits/flashcopper.html
>
> Once Jeremy tells us what to use to make the holes conductive, we
> have all crucial details to make plated holes in a homebrew

> right?
>
> Mike
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Jeremy Taylor"

> wrote:
> > Adam
> > Flash copper (Alkaline) works better for me than acid copper.

> the future you might just want to say "copper plating"

> out as there is more than one way to plate copper.
> >
> > A quick dip in HOT tsp (tri sodium phosphate) does a great job

> pre-plate - pre lamination cleaning, and I suspect it would also

> well for tt (no sandpaper needed)
> >
> > JT
> >
> > ----- Original Message -----
> > From: Adam Seychell
> > To: Homebrew_PCBs@yahoogroups.com
> > Sent: Thursday, July 29, 2004 9:05 PM
> > Subject: Re: [Homebrew_PCBs] Re: Plating thruholes.
> >
> >
> > Dave Mucha wrote:
> > > --- In Homebrew_PCBs@yahoogroups.com, "mikezcnc"

> wrote:
> > >
> > >>I searched but weren't able to locate any posts on the

> but
> > >
> > > I
> > >
> > >>recall that tehre was a dicussion of it. Does anyone know a
> simple
> > >>method that works on plating holes in a PCB? Mike
> > >
> > >
> > > I think the best home-brew (closer to professional sho)

> from
> > > Markus
> > >
> > > http://www.myhome.ch/mzingg/pcbstuff/tps/
> > >
> > >
> > > Also go back to the posts around 1100, maybe go directly to
> 1108 and
> > > start reading. IIRC, there was a detailed list of each

> needed.
> > >
> > > This is not for the faint of heart nor a simple one shot
> project.
> >
> > This is very true. The electroplating, and application of

> own
> > photoresists is the other major parts of the PTH process.
> >
> > In addition to etching, and photo imaging, you must;
> >
> > 1) cleaning PCB surface to prepare for electroplating.
> > 2) ability to apply your own dry film photoresist
> > 3) give holes the ability to plate.
> > 4) setup acid copper electroplating tank with proprietary
> additives.
> >
> > There are several methods of doing (3), such as with carbon
> dispersion,
> > electroless copper solutions, or with palladium colloid
> solutions. I
> > believe Markus's setup is using the palladium colloid

> All
> > three processes have their problems, and I would say the most
> critical
> > step in the process.
> >
> > Let me know if you have any questions.
> >
> > Adam
> >
> >
> > Be sure to visit the group home and check for new Bookmarks

> files:
> > http://groups.yahoo.com/group/Homebrew_PCBs
> >
> >
> > Yahoo! Groups Sponsor
> > ADVERTISEMENT
> >
> >
> >
> >
> >
> > ----------------------------------------------------------------

> ----------
> > Yahoo! Groups Links
> >
> > a.. To visit your group on the web, go to:
> > http://groups.yahoo.com/group/Homebrew_PCBs/
> >
> > b.. To unsubscribe from this group, send an email to:
> > Homebrew_PCBs-unsubscribe@yahoogroups.com
> >
> > c.. Your use of Yahoo! Groups is subject to the Yahoo!

> Service.
> >
> >
> >
> > [Non-text portions of this message have been removed]
>
>
>
> Be sure to visit the group home and check for new Bookmarks and

> http://groups.yahoo.com/group/Homebrew_PCBs
>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
>
>
>
> --------------------------------------------------------------------

> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
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>
> b.. To unsubscribe from this group, send an email to:
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>
> c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of

>
>
>
> [Non-text portions of this message have been removed]

> 3. I would like a chemist to tell us how does IPA clean, because it
> does not dissolve oils nor fats. And if it doesn't then what kind

> principle is applied for cleaning with it?
>
> Mike

>
> > 3. I would like a chemist to tell us how does IPA clean, because

> > does not dissolve oils nor fats. And if it doesn't then what kind
> of
> > principle is applied for cleaning with it?
> >
> > Mike
>
>
> http://scifun.chem.wisc.edu/chemweek/FatsOils/Fats&Oils.html

> That's funny, Dave.

>
> Mike
>
> --- In Homebrew_PCBs@yahoogroups.com, "Dave Mucha"

> wrote:
> >
> > > 3. I would like a chemist to tell us how does IPA clean,

> it
> > > does not dissolve oils nor fats. And if it doesn't then what

> > of
> > > principle is applied for cleaning with it?
> > >
> > > Mike
> >
> >
> > http://scifun.chem.wisc.edu/chemweek/FatsOils/Fats&Oils.html

----- Original Message -----
From: mpdickens
To: Homebrew_PCBs@yahoogroups.com
Sent: Friday, July 30, 2004 5:52 PM
Subject: [Homebrew_PCBs] Inkjet printers, transparencies and UV light...


A member of another mailing list I am a member of
found the following in a archive. Further, he tested
and it worked as advertised:

I have been dealing with a development effort for a
circuit that my company is developing. In order to get
fast turnaround of boards for testing, I needed a way
to make high quality circuit boards (multilayer) in
under 8 hours. Cost from commercial board houses for
24 hour turnaround was in the range of $2000-$3000 per
design. In my case, I had to also develope plating
systems and through-hole activation, fast etching, and
a hot 20 ton press which I built by converting a shop
press from harbor freight and adding a temperature
controller and heating elements. etc.

For ATM purposes, 2 sided boards can be made for a
minimal expense.

Because many on this list make their own circuit
boards on occassion (for stepper circuits and camera
circuits), I thought I would share my experience
with the group.

I am currently producing 4, 6 and 8 layer circuit
boards using equipment now in my basement. Granted my
basement looks like a chamber of horrors, but I
suspect this is true for many on this list. Eight mil
traces and lands are now easily doable and I am
holding +/- 2 mil registration.

The greatest roadblock to producing good circuit
boards was getting good artwork on a transparency. In
that regard, I have made several discoveries which are
not immediately intuitive.

First, getting really good artwork for the spec above
is not possible with a laser printer. Phase error
creeps in and even for printers claiming 1200
DPI the accuracy just isn't there. I tested this with
several models of HP printers including the 2000
series and the 4000 series.

In addition, the toner is just not dark enough. You
end up having to underexpose the photoresist in order
to get good removal and then you have a problem with
undercured photoresist that will not tent over holes
and whose sides are weak. Further the developing
process just trashes the underexposed resist.

I finally decided to try an inkjet printer. After
some research looking for a printer that supported
high resolution in black, I purchased a Canon.
Initially, I purchased the S300 but it turned out that
clever marketing made is sound like it supported high
res black. In reality, the black was only 600 DPI
like every other printer... Not enough resolution. I
then tried the S800, which did support 2400 x 1200 DPI
in color and in Black - the only printer that
supported high resolution black printing. Experiments
with
this printer unfortunately revealed the problem that
most people have with bubble jets. The black is
simply not dark enough in UV. This despite the fact
that it was a pigment based ink.

I did have moderate success stacking tranparenies.
This allowed me to increase the exposure time, but
because only the first transparency was ink down (the
second had to have a full 5 mil separation for the
thickness of the first transparency, the edges were
not very clean.

I then had a brainstorm, I realized that my UV filters
for my flourescent lighting were amber. I decided to
try other colors... I quickly discovered that yellow
was just as dark (in UV) as black. Disappointed that
it was not darker, I began thinking about ways I could
change the formulation of the ink to include a
coreactive UV blocking chemical. I started searching
the net when I discovered that ink fading as a result
of UV is a real problem for photography. To my
surprise, my printer already contained an ink that
was UV blocking. All I had to do was tell the printer
that it was printing on high resolution photopaper.
This automatically switched cartridges to the PC
(Photo Cyan) and PM (Photomagenta). Yellow remains the
same because yellow only fades to yellow.

In any case, once I did that, I was able to fully
expose the Photoresist. In comparing a foil blocked
section and a photo ink exposed section there
was little difference. Moreover, in testing artwork
created by a real photoplotter (costing $200,000).
There was no difference. The only difference was that
I settled on "GREEN" as being the color that was best.
This selected the darkness of yellow in UV and the
chemical UV blocking in Photo Cyan to produce a very
dark black in UV and a pretty green in visible... :-)

Perfect exposures! That along with unbelievable
resolution of these printers make for a killer
combination for producing your own artwork and
consequently your own circuit boards.

The bottom line is this. You DON'T want a printer with
a dark black! Forget whether it is pigment based ink
or dye based ink. That is all irrelavent, none of them
are going to be dark enough.

You want a PHOTO printer with PHOTO ink. Further ALL
photoprinters have high resolution in color! Even the
cheap ones ($100)! Just make sure a photo ink is
available either from the manufacturer or for an ink
refiller. All photo ink is, is ink with UV blocking
added so the photos you print don't fade.

What will the photoplotter companies do???

Armed with this information, there is no reason
everyone on this list does not do steves killer mod
for the Philips Vesta camera or the many circuits
for telescope motorization and tracking.


Best

Marvin Dickens
Alpharetta, Georgia

=====
Registered Linux User No. 80253
If you use linux, get counted at:
http://www.linuxcounter.org



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c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.



[Non-text portions of this message have been removed]

> A member of another mailing list I am a member of
> found the following in a archive. Further, he tested
> and it worked as advertised:
>
> I have been dealing with a development effort for a
> circuit that my company is developing. In order to get
> fast turnaround of boards for testing, I needed a way
> to make high quality circuit boards (multilayer) in
> under 8 hours. Cost from commercial board houses for
> 24 hour turnaround was in the range of $2000-$3000 per
> design. In my case, I had to also develope plating
> systems and through-hole activation, fast etching, and
> a hot 20 ton press which I built by converting a shop
> press from harbor freight and adding a temperature
> controller and heating elements. etc.
>
> For ATM purposes, 2 sided boards can be made for a
> minimal expense.
>
> Because many on this list make their own circuit
> boards on occassion (for stepper circuits and camera
> circuits), I thought I would share my experience
> with the group.
>
> I am currently producing 4, 6 and 8 layer circuit
> boards using equipment now in my basement. Granted my
> basement looks like a chamber of horrors, but I
> suspect this is true for many on this list. Eight mil
> traces and lands are now easily doable and I am
> holding +/- 2 mil registration.
>
> The greatest roadblock to producing good circuit
> boards was getting good artwork on a transparency. In
> that regard, I have made several discoveries which are
> not immediately intuitive.
>
> First, getting really good artwork for the spec above
> is not possible with a laser printer. Phase error
> creeps in and even for printers claiming 1200
> DPI the accuracy just isn't there. I tested this with
> several models of HP printers including the 2000
> series and the 4000 series.
>
> In addition, the toner is just not dark enough. You
> end up having to underexpose the photoresist in order
> to get good removal and then you have a problem with
> undercured photoresist that will not tent over holes
> and whose sides are weak. Further the developing
> process just trashes the underexposed resist.
>
> I finally decided to try an inkjet printer. After
> some research looking for a printer that supported
> high resolution in black, I purchased a Canon.
> Initially, I purchased the S300 but it turned out that
> clever marketing made is sound like it supported high
> res black. In reality, the black was only 600 DPI
> like every other printer... Not enough resolution. I
> then tried the S800, which did support 2400 x 1200 DPI
> in color and in Black - the only printer that
> supported high resolution black printing. Experiments
> with
> this printer unfortunately revealed the problem that
> most people have with bubble jets. The black is
> simply not dark enough in UV. This despite the fact
> that it was a pigment based ink.
>
> I did have moderate success stacking tranparenies.
> This allowed me to increase the exposure time, but
> because only the first transparency was ink down (the
> second had to have a full 5 mil separation for the
> thickness of the first transparency, the edges were
> not very clean.
>
> I then had a brainstorm, I realized that my UV filters
> for my flourescent lighting were amber. I decided to
> try other colors... I quickly discovered that yellow
> was just as dark (in UV) as black. Disappointed that
> it was not darker, I began thinking about ways I could
> change the formulation of the ink to include a
> coreactive UV blocking chemical. I started searching
> the net when I discovered that ink fading as a result
> of UV is a real problem for photography. To my
> surprise, my printer already contained an ink that
> was UV blocking. All I had to do was tell the printer
> that it was printing on high resolution photopaper.
> This automatically switched cartridges to the PC
> (Photo Cyan) and PM (Photomagenta). Yellow remains the
> same because yellow only fades to yellow.
>
> In any case, once I did that, I was able to fully
> expose the Photoresist. In comparing a foil blocked
> section and a photo ink exposed section there
> was little difference. Moreover, in testing artwork
> created by a real photoplotter (costing $200,000).
> There was no difference. The only difference was that
> I settled on "GREEN" as being the color that was best.
> This selected the darkness of yellow in UV and the
> chemical UV blocking in Photo Cyan to produce a very
> dark black in UV and a pretty green in visible... :-)
>
> Perfect exposures! That along with unbelievable
> resolution of these printers make for a killer
> combination for producing your own artwork and
> consequently your own circuit boards.
>
> The bottom line is this. You DON'T want a printer with
> a dark black! Forget whether it is pigment based ink
> or dye based ink. That is all irrelavent, none of them
> are going to be dark enough.
>
> You want a PHOTO printer with PHOTO ink. Further ALL
> photoprinters have high resolution in color! Even the
> cheap ones ($100)! Just make sure a photo ink is
> available either from the manufacturer or for an ink
> refiller. All photo ink is, is ink with UV blocking
> added so the photos you print don't fade.
>
> What will the photoplotter companies do???
>
> Armed with this information, there is no reason
> everyone on this list does not do steves killer mod
> for the Philips Vesta camera or the many circuits
> for telescope motorization and tracking.
>
>
> Best
>
> Marvin Dickens

> The black ink in my old Epson 660 is extremely UV
> blocking. I can expose a PCB over 5 times normal and
> still not manage to effect the dark areas.

> --- Adam Seychell <a_seychell@...> wrote:
>
>
>>The black ink in my old Epson 660 is extremely UV
>>blocking. I can expose a PCB over 5 times normal and
>>still not manage to effect the dark areas.
>
>
> Well, I'm no expert in the area of optical physics.
>

> OTOH, this may be a total load of bullsh!t and a waste
> of my time. I'll let you know...
>
>

--- In Homebrew_PCBs@yahoogroups.com, "mikezcnc" <eemikez@c...> wrote:
> Stefan,
>
> I would like three issues answered by a chemist and or pharmacist
> (although here I suspect that argument would be made that since it
is
> used for rubbing then it must be ok:
>
> 1. The web search reveals that IPA causes cancer. We might get into
> semantics on that one, but we should not use an argument of rubbing
> alcohol being healthy, therfeore and the reason being that that
> discussion might turn in to medical subject which I won't get into.
I
> know it is carcinogennic and if someone believes otherwise, I can
> respect that.

> Jimbo,
>
> i thank you for replying but in the future when steve the moderator
> closes a topic you better do what he says.

> --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
> <stefan_trethan@g...> wrote:
> > Jimbo,
> >
> > i thank you for replying but in the future when steve the

> > closes a topic you better do what he says.
>
> Then if Steve asks you to stop playing webcop, shouldn't you listen?
>
> ;')
>
> Steve, the listowner

> --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
> <stefan_trethan@g...> wrote:
>> Jimbo,
>>
>> i thank you for replying but in the future when steve the moderator
>> closes a topic you better do what he says.
>
> Then if Steve asks you to stop playing webcop, shouldn't you listen?
>
> ;')
>
> Steve, the listowner

> On Wed, 04 Aug 2004 02:31:08 -0000, Steve <alienrelics@y...> wrote:
>
> > --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
> > <stefan_trethan@g...> wrote:
> >> Jimbo,
> >>
> >> i thank you for replying but in the future when steve the

> >> closes a topic you better do what he says.
> >
> > Then if Steve asks you to stop playing webcop, shouldn't you

> >
> > ;')
> >
> > Steve, the listowner
>
> You can hardly stop me suggesting things ;-)
>
> ST

> while steve is pretty reasonable, I wouldn't go challenging him. Mod
> is God...

----- Original Message -----
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, August 04, 2004 9:35 AM
Subject: [Homebrew_PCBs] advanced routing


> Hi,
>
> i was wondering if there is a tutorial for advanced routing.
> I mean as soon as you have two layers and more than 100components
> it starts to get more difficult.
> If there is no tutorial we could maybe exchange some tricks.

I've looked and I don't think there is one.

Here are a few 'rules of thumb' I've come across which I find very useful:

>
> How do you start?

Start placement with the largest parts.

> How do you decide which parts are on which side?

> (i put the SMD ones on top which can be connected to throughhole without
> adding a via, and i aim for the same population density top and bottom.)

For low-cost manufacture it's best to put all the SMDs on the top. If you
put them on top and bottom your technique seems OK.

>
> Often it is required to rotate and rearrange parts to get a good layout,
> but at a certain number of parts it is very hard to keep track of things.

Try to keep the components in functional blocks, like in the schematic. An
autorouter can be useful, even if you are routing manually, to show where
there are going to be problems. If you are using an autorouter, here are
some tips:

http://www.connecteda.com/doc/Autorouting%20Techniques.pdf

They are applicable to any autorouter. BTW, that Electra autorouter is
*very* good, it's now supplied with the Pulsonix software I use.

>
> Do you start routing with special nets, like supply?

Critical nets like power and ground, and clocks, etc. should always be
routed first.

>
> You see, the methods i used for years on smaller circuits seem very, very
> hard
> to apply to bigger circuits, and i believe there must be some tricks i
> don't
> know yet.
> Maybe if everyone throws in a few ideas we can all learn something.

Placement is the important thing, once that is optimised the actual routing
should be quite easy, until you get to the last few tracks - they will take
as long as all the others put together. 8-)

Always start by routing the shortest tracks, working up to the longest. That
is probably the most important rule.


> I always use different color "rubber bands" for GND and VCC which helps a
> bit.

That can help a lot. The software I use highlights an entire net when it is
selected. I can use different colours for different nets, as well.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

> Hi Stefan
>
> When I routed boards at work a couple of years ago I often made 2-layer
> boards with the classic vertical traces at one side and horizontal at
> the other.
>
> I used to start routing the Power and Gnd , then I routed important
> signals manually .
>
> Then I locked that traces and used the autorouter for the remaining.
>
> After that came the part when you fix the traces not solved and final
> touch up.
>
> Last we often placed a Gnd area to fill up all unused areas of the
> board.
>
>
> // Gunnar Lestander , SM4VLM
>

> I know that approach, but it leads to a lot of vias, which i don't
>want tosolder.

> Also it seems to work better with throughhole and less good with
>hybrid boards.

> For the Midnight Board Maker each via represent a problem so the less
> the merrier...
>
> Gunnar Lestander

> That can help a lot. The software I use highlights an entire net when it

> selected. I can use different colours for different nets, as well.

>
> http://europa.eu.int/comm/environment/ppps/ma_reding_annex2.pdf

>
> Just use common sense and practice standard industrial hygene: limit
> exposure with appropriate clothing and practices, and wash of
> accidental exposures without delay, and then QUIT WORRYING!

----- Original Message -----
From: "Alexandre Souza" <alexandre-listas@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, August 04, 2004 2:17 PM
Subject: Re: [Homebrew_PCBs] advanced routing


> > That can help a lot. The software I use highlights an entire net when it
> is
> > selected. I can use different colours for different nets, as well.
>
> Leon, can you say more about the software you use, and how it compares
> to Protel?

I've used Pulsonix since it first came out: http://www.pulsonix.com

I'm one of their beta testers, so I'm biased. Try the demo (100 pins limit).
They will give you a fully working 30 day license if you need to check it
properly.

I tried the latest Protel, just out of curiosity. It's rather slow on my
hardware, and difficult to use. It has lots more features than PSX, but they
aren't very useful, IMO. It's also a lot more expensive and has lots of
bugs, according to the PEDA list, which they don't fix until the next
release. The autorouter is still unusable, apparently. PSX has very few bugs
(I and the other testers catch most of them) and they get fixed immediately
they are reported.

I formed a PSX users group: http://groups.yahoo.com/group/PulsonixUG/. It
gets very little use, because the product is so easy to use and the support
is so good.

Leon

> Hi List.
> Any idea where to find free or cheap Standalone Milling Isolation

> other than Eagle?
> Cristian

> ----- Original Message -----
> From: "Stefan Trethan" <stefan_trethan@g...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, August 04, 2004 9:35 AM
> Subject: [Homebrew_PCBs] advanced routing
>
>
> > Hi,
> >
> > i was wondering if there is a tutorial for advanced routing.
> > I mean as soon as you have two layers and more than 100components
> > it starts to get more difficult.
> > If there is no tutorial we could maybe exchange some tricks.
>
> I've looked and I don't think there is one.
>
> Here are a few 'rules of thumb' I've come across which I find very

>
> >
> > How do you start?
>
> Start placement with the largest parts.
>
> > How do you decide which parts are on which side?
>
> > (i put the SMD ones on top which can be connected to throughhole

> > adding a via, and i aim for the same population density top and

>
> For low-cost manufacture it's best to put all the SMDs on the top.

> put them on top and bottom your technique seems OK.
>
> >
> > Often it is required to rotate and rearrange parts to get a good

> > but at a certain number of parts it is very hard to keep track of

>
> Try to keep the components in functional blocks, like in the

> autorouter can be useful, even if you are routing manually, to show

> there are going to be problems. If you are using an autorouter,

> some tips:
>
> http://www.connecteda.com/doc/Autorouting%20Techniques.pdf
>
> They are applicable to any autorouter. BTW, that Electra autorouter

> *very* good, it's now supplied with the Pulsonix software I use.
>
> >
> > Do you start routing with special nets, like supply?
>
> Critical nets like power and ground, and clocks, etc. should always

> routed first.
>
> >
> > You see, the methods i used for years on smaller circuits seem

> > hard
> > to apply to bigger circuits, and i believe there must be some

> > don't
> > know yet.
> > Maybe if everyone throws in a few ideas we can all learn

>
> Placement is the important thing, once that is optimised the actual

> should be quite easy, until you get to the last few tracks - they

> as long as all the others put together. 8-)
>
> Always start by routing the shortest tracks, working up to the

> is probably the most important rule.
>
>
> > I always use different color "rubber bands" for GND and VCC which

> > bit.
>
> That can help a lot. The software I use highlights an entire net

> selected. I can use different colours for different nets, as well.
>
> Leon
> --
> Leon Heller, G1HSM
> http://www.geocities.com/leon_heller

> > Any idea where to find free or cheap Standalone Milling Isolation
>Software,
> > other than Eagle?
> > Cristian
>
>Try this one next. The board size might be limited
>
>http://ibfriedrich.com/

----- Original Message -----
From: "Phil" <phil1960us@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, August 04, 2004 5:57 PM
Subject: [Homebrew_PCBs] Re: advanced routing


> Lots of good ideas, Leon. I use most of them as well. Wish eagle
> allowed the colored "air wire" thing as i spend too much time
> checking to see it is a supply connection.
>
> My wife did PCB design for many years and I asked her the advanced
> routing question. She just laughed, shook her head and
> said "beginners. there is no magic book". No suprise to me. It just
> boils down to a set of design rules and techniques. There is no
> substitution for experience.
>
> A couple more thoughts:
>
> I spend a lot of time looking at the schematic trying to get a sense
> of what goes best with what. This helps me to place components in
> their best position. I have a dual monitor set up so I can keep the
> board on one screen and the schematic on the other. That really
> speeds up placement.

I do that as well. Pulsonix has a 'Group' facility that allows components to
be grouped on the schmatic so that they are associated on the PCB but I keep
forgetting to use it.

>
> For pins that are swappable, I will change the schematic to simplify
> the layout. By swappable, I mean any pins that can be exchanged for
> same function. For examnple, a hex not gate has 6 inputs and 6
> outputs that can be used for the same purpose. swapping gate 1 for 2
> may lead to simpler layout. Same thing for microprocessor register
> pins (non-dedicated ones, of course). Headers are another place
> where you might be able to move things around to simplify layout. I
> guess PLDs are the ultimate case. I bop back and forth between the
> schematic and board swapping things around, often to significant
> improvement. Clearly, there are times when you dont want to
> complicate programming but who cares if a function is on port B pin 1
> or 2, for example. Its kind of a pet peeve of mine that chip
> designers don't always consider layout complexity when they assign
> pins. Compare AVR vs midrange PIC in system programming pins, for
> example (AVR got it right).

Pulsonix allows 'swappable' pins and gates to be swapped on the PCB, and the
schematic may then be back-annotated.

>
> By the way, I also put SMDs on the "solder" side when doing mixed
> TH/SM layouts to avoid vias for boards I'm making myself. If it
> prevents a drill hole, it is good. But then if I'm using a board
> house, I dont care, so viva las vias!

I have to put SMDs on the underside, as all my boards are single-sided. I
really ought to start making my own DS boards.

Leon

> Hi List.
> Any idea where to find free or cheap Standalone Milling Isolation

> other than Eagle?
> Cristian

> > Leon, can you say more about the software you use, and how it

> > to Protel?
> I've used Pulsonix since it first came out: http://www.pulsonix.com

----- Original Message -----
From: "Alexandre Souza" <alexandre-listas@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, August 04, 2004 7:51 PM
Subject: Re: [Homebrew_PCBs] advanced routing


> > > Leon, can you say more about the software you use, and how it
> compares
> > > to Protel?
> > I've used Pulsonix since it first came out: http://www.pulsonix.com
>
> And what about the libraries? And the price?
>
> I'm looking for a REASONABLY PRICED (no, protel isn't reasonably
priced)
> tool for PCB use, maybe pulsonix can have a chance.

The libraries are quite good, some mistakes though. Most people make their
own, anyway.

Prices start at $3,000, IIRC. Prices are on the web site. Easy-PC (same
company) is very good also, it's intended more for the hobbyist market:

http://www.numberone.com

Prices start at under $200.

Leon

> >
> > http://europa.eu.int/comm/environment/ppps/ma_reding_annex2.pdf
>
> Very interesting article. It seems from reading the article that

> what chemicals are and are not carcinogenic is going to take a lot more
> time and effort (i.e $$$) than before.

> ----- Original Message -----

>
> Pulsonix allows 'swappable' pins and gates to be swapped on the

> schematic may then be back-annotated.
>

> >
> > By the way, I also put SMDs on the "solder" side when doing mixed
> > TH/SM layouts to avoid vias for boards I'm making myself. If it
> > prevents a drill hole, it is good. But then if I'm using a board
> > house, I dont care, so viva las vias!
>
> I have to put SMDs on the underside, as all my boards are single-

> really ought to start making my own DS boards.

----- Original Message -----
From: "Phil" <phil1960us@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, August 05, 2004 6:01 AM
Subject: [Homebrew_PCBs] Re: advanced routing


> --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller"
> <leon_heller@h...> wrote:
> > ----- Original Message -----
> ...
> >
> > Pulsonix allows 'swappable' pins and gates to be swapped on the
> PCB, and the
> > schematic may then be back-annotated.
> >
>
> eagle does too for pins but not gates. does psx? also, I suspect
> no layout sw allows uP register pins to be swapped.

Yes, it swaps gates. Any pins can be set for swap.

Leon

> Hi,
>
> i was wondering if there is a tutorial for advanced routing.
> I mean as soon as you have two layers and more than 100components
> it starts to get more difficult.
> If there is no tutorial we could maybe exchange some tricks.
>
> How do you start?
> How do you decide which parts are on which side?
> (i put the SMD ones on top which can be connected to throughhole

> adding a via, and i aim for the same population density top and

>
> Often it is required to rotate and rearrange parts to get a good

> but at a certain number of parts it is very hard to keep track of

>
> Do you start routing with special nets, like supply?
>
> You see, the methods i used for years on smaller circuits seem

> hard
> to apply to bigger circuits, and i believe there must be some

> don't
> know yet.
> Maybe if everyone throws in a few ideas we can all learn something.
>
> I always use different color "rubber bands" for GND and VCC which

> bit.
>
> ST

> Nah i don' think he's goin to kick my ass outa' here.
> If he wants having me contribute to the discussion he must endure
> my comments from time to time. If i find something out of order
> i will say so, nothing wrong with that. Everyone seems to ignore
> me anyway as they know i can't do a thing.

> ----- Original Message -----
> From: "Phil" <phil1960us@y...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Thursday, August 05, 2004 6:01 AM
> Subject: [Homebrew_PCBs] Re: advanced routing
>
>
> > --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller"
> > <leon_heller@h...> wrote:
> > > ----- Original Message -----
> > ...
> > >
> > > Pulsonix allows 'swappable' pins and gates to be swapped on the
> > PCB, and the
> > > schematic may then be back-annotated.
> > >
> >
> > eagle does too for pins but not gates. does psx? also, I

> > no layout sw allows uP register pins to be swapped.
>
> Yes, it swaps gates. Any pins can be set for swap.
>
> Leon

----- Original Message -----
From: "Phil" <phil1960us@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, August 05, 2004 7:25 PM
Subject: [Homebrew_PCBs] Re: advanced routing


> By swapping gates, do you mean that you can point to two different
> not gates (or nors or nands), say swap and it will swap inputs AND
> outputs? If so, that's pretty cool.

I think it does. I never use it. I do use pin swapping quite a lot, though.

Leon

> Stefan,
>
> Mariss Friemanis of Gecko drives mentioned some good information
> about how he lays out his SMD VERY densely populated drives. It
> involved some "strange" values for the layout grid, and included

> thought about where to run vias and ancillary parts...
>
> Un fortunately, I'm not sure where I filed it. But he's known to be
> quite helpful, and hangs out at several groups including the
> electronics 101 group that I think belongs to our list owner here?

> --- In Homebrew_PCBs@yahoogroups.com, "ballendo" <ballendo@y...>
> wrote:

> > quite helpful, and hangs out at several groups including the
> > electronics 101 group that I think belongs to our list owner here?

> correct, it was on Electronics-101

> WinQCAD is a more user interface friendly software than Eagle.
>
> Heck, even I can use it.
>
> It has an internal CNC output so you can go directly from schematic
> to board layout to CNC output for you drilling and/or milling.
>
> Also, there are many free conversion programs from Gerber output

>
> Dave

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> By swapping gates, do you mean that you can point to two different
> not gates (or nors or nands), say swap and it will swap inputs AND
> outputs? If so, that's pretty cool.
>
> --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller"
> <leon_heller@h...> wrote:
> > ----- Original Message -----
> > From: "Phil" <phil1960us@y...>
> > To: <Homebrew_PCBs@yahoogroups.com>
> > Sent: Thursday, August 05, 2004 6:01 AM
> > Subject: [Homebrew_PCBs] Re: advanced routing
> >
> >
> > > --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller"
> > > <leon_heller@h...> wrote:
> > > > ----- Original Message -----
> > > ...
> > > >
> > > > Pulsonix allows 'swappable' pins and gates to be swapped on
the
> > > PCB, and the
> > > > schematic may then be back-annotated.
> > > >
> > >
> > > eagle does too for pins but not gates. does psx? also, I
> suspect
> > > no layout sw allows uP register pins to be swapped.
> >
> > Yes, it swaps gates. Any pins can be set for swap.
> >
> > Leon

> I searched but weren't able to locate any posts on the subject but

> recall that tehre was a dicussion of it. Does anyone know a simple
> method that works on plating holes in a PCB? Mike

> Solder pins (the ones for which you can buy plugs (1mm and 1.3mm)
> make nice vias. use them instead of "wire soldered to the board"

> and have a easy-to-solder free via.
> ...
> ST

> Sounds very interesting! Could you provide a manufacturer and a
> source?

> On Thu, 12 Aug 2004 02:54:12 -0000, flyrgeorge <jfritz@n...> wrote:
>
> > Sounds very interesting! Could you provide a manufacturer and a
> > source?
>
> <http://www.elcomp.at/Sit-Grup/Gr10/10-03-03C-Stifte-Osen-

>
> But they are so widespread and common you can find a source closer

>
> ST

>> <http://www.elcomp.at/Sit-Grup/Gr10/10-03-03C-Stifte-Osen-
> Leisten.htm>
>>


> HEre is the link to Digi-key.
>
> I sometimes use these ED5038 pin recepticles.
>
> they are similar to DIP sockets. You can use DIP sockets and cut the
> pins out and then break off the little end bits for a similar
> socket. the neat thing is that they come in different sizes and you
> can use them as quick sockets for caps or resistors.
>
> http://dkc3.digikey.com/PDF/T042/0276.pdf
>
> They come in many different hole dimeters and lenghts but make sure
> you get the holes that will fit the pins you want to use.
>
> They can be soldered on top and bottom to make vias.
>
> Dave
>

> When the subject of conductive silver paint arises, it usually gets
> sidetracked into the use of activators, copper plating etc, but
> nobody so far seems to have tried using silver paint to create the
> actual body of the vias. According to the manufacturers, a typical
> paint has a resistance of 200 microOhms per cm, and it can be
> thinned. 2 or 3 applications should be enough. Whilst it is
> expensive, I would imagine 3 grammes of the stuff would go a heck

> a long way.

> When the subject of conductive silver paint arises, it usually gets
> sidetracked into the use of activators, copper plating etc, but
> nobody so far seems to have tried using silver paint to create the
> actual body of the vias. According to the manufacturers, a typical
> paint has a resistance of 200 microOhms per cm, and it can be
> thinned. 2 or 3 applications should be enough. Whilst it is
> expensive, I would imagine 3 grammes of the stuff would go a heck

> a long way.

> Personally, with soldering a scrap piece of wire, or using one of

> other discussed via methods being so easy (and repairable) I will

> be spending the money on the paint. Remember, when paint dries it
> tends to become brittle and possibly even crack with heat. I guess

> it really worked that good/reliably, the "big boys" would be using
> something like that on the professional boards. Just a thought.
>
> Keep us posted if you decide to try it.
> Mike R.

> It looks like I'm going to be the one to save up £6 and nip down
> to Maplins some time (Farnell, RS etc are the same price). Quite a
> few people seem to have success using it for bridging clock divider
> pins on AMD processors, so I imagine thermal cycling (and fairly high
> temperature) isn't a problem for the modern stuff. In fact, according
> to the data sheets it seems that curing it at 85deg C or so gives a
> lower resistance.
>

> I still don't like the paint, it is ridiculously expensive.
> I'm also not sure how it would be applied in a hole, and i doubt it
> is faster than soldering a via.

> > I still don't like the paint, it is ridiculously expensive.
> > I'm also not sure how it would be applied in a hole, and i doubt

> > is faster than soldering a via.
>
>
> I can't read seven thousand posts, so I don't know if this method

> been presented before. But in case it hasn't:
>
> 1. When laying out PCB, take note of the component type and don't
> depend on a through-hole connection for devices that sit over the

>
> 2. Strip about a foot of fine copper wire and *lace* through many

> at once.
>
> 3. Solder vias, strip more wire if necessary and repeat. Lacing the
> wire through the board will hold it in place while you solder.
>
> 4. Cut off excess wire flush to board, and solder the rest of the
> components.
>
> This is about the fastest way possible. Even the little plugs

> you to solder both sides, and any electroplating process takes a

> amount of time and effort. It just takes a small amount of

> when laying out the PCB.

> I still don't like the paint, it is ridiculously expensive.
> I'm also not sure how it would be applied in a hole, and i doubt it
> is faster than soldering a via.

>
> That sounds pretty good; fast and easy.
>
> I am laying out some two-sided boards, at the moment. I would like to use
> 2x20 pin headers, with some surplus (new) IDE cables that I got (200
> of them, new, for $5!), to make board-to-board connections.
>
> One problem is that the headers sit flat on the board. So in order to
> connect them to both sides, it seems like I'll have to put another row
> of holes next to each side, and solder on both sides of those holes.

> It sure seems like there ought to be a much easier, "cleaner" way,

>
> Regards,
>
> Tom Gootee

> It sure seems like there ought to be a much easier, "cleaner" way,

>
> ***ORIGINAL MESSAGE:
>
> Date: Thu, 19 Aug 2004 12:44:52 -0000
> From: "cybermace5" <cybermace5@y...>
> Subject: making vias (was: Re: Plating thruholes.)
>
> > I still don't like the paint, it is ridiculously expensive.
> > I'm also not sure how it would be applied in a hole, and i doubt

> > is faster than soldering a via.
>
>
> I can't read seven thousand posts, so I don't know if this method

> been presented before. But in case it hasn't:
>
> 1. When laying out PCB, take note of the component type and don't
> depend on a through-hole connection for devices that sit over the

>
> 2. Strip about a foot of fine copper wire and *lace* through many

> at once.
>
> 3. Solder vias, strip more wire if necessary and repeat. Lacing the
> wire through the board will hold it in place while you solder.
>
> 4. Cut off excess wire flush to board, and solder the rest of the
> components.
>
> This is about the fastest way possible. Even the little plugs

> you to solder both sides, and any electroplating process takes a

> amount of time and effort. It just takes a small amount of

> when laying out the PCB.
>
> ------------------------------------
>
> ***REPLY:
>
> That sounds pretty good; fast and easy.
>
> I am laying out some two-sided boards, at the moment. I would like

> 2x20 pin headers, with some surplus (new) IDE cables that I got (200
> of them, new, for $5!), to make board-to-board connections.
>
> One problem is that the headers sit flat on the board. So in order

> connect them to both sides, it seems like I'll have to put another

> of holes next to each side, and solder on both sides of those

> am considering just sticking some single-row 1x20 headers in them,

> upside-down so the long ends of the pins are in the holes, and

> the pins partially sticking out of both sides of the board and then

> on both sides, at each pin. Seems like a lot of fuss, though, just

> a header on a two-sided board. (Although it WILL provide nicely-

> test-points...)
>
> One problem, in this particular case, is that I'm modifying an

> board design, to eliminate all of the wires that used to get

> to the board. So I'm putting all of the new traces, from the
> wire-connection-points to the headers, on the TOP of the board,

> the headers, so the ribbon cables can be plugged in from the top.

> boards are mounted horizontally, on the bottom of a cabinet.)
>
> It sure seems like there ought to be a much easier, "cleaner" way,

>
> Regards,
>
> Tom Gootee
>
> http://www.fullnet.com/u/tomg
>
> ------------------------------------
>
>
> [Non-text portions of this message have been removed]

> Thanks, to everyone who replied so far, for the good suggestions and
> information!
>
> This re-design is still in the very early stages. I don't know if this
> is too off-topic. But I'll post a sort of summary of the different
> board/connector options I'm considering (mostly copied from an email
> that I sent to a friend, recently, about this stuff). Maybe some of you
> can set me straight, or offer some practical tips, or some ideas.
>

On Friday 20 August 2004 03:41 pm, Thomas P. Gootee wrote:

> There are several possibilities that I have considered:
>
> 1) pin headers on each pcb, with ribbon cables running to similar headers
> on the front panel's new pcb, or

Pin headers are good reliable connectors, particularly if shrouded connectors
are used, and if they're also using ejector levers there isn't much stress
on the cabling.

> 2) card-edge connectors on the front panel pcb, along the bottom, that each
> of the three pcboards' edges could plug into, or

I think less well of card-edge connectors. You'll have problems with tarnish
on the card, and lack of reliability eventually with the connectors over
time. Notice that card-edge was the way to go with the old 5.25" and 8"
floppy drives, and early hard drives as well. Nowadays _all_ 3.5" floppy
drives and all IDE and SCSI hard drives use pin connectors. That should tell
you something. :-)

> 3) right-angle headers or sockets on each pcb, that would plug directly
> into straight headers or sockets on the front panel pcb (pin headers and
> sockets, or DIN, or even D-Sub), with NO CABLING necessary, or

Pin headers at both ends of the connection is workable, provided you can
arrange the layout of stuff to accomodate this without too much trouble, but
it's gonna be a real hassle to design, compared to using cables.

> 4) another new board, a "motherboard", in the bottom of the enclosure, with
> card-edge sockets, along with a total redesign of the current boards'
> layouts, so they could be mounted vertically, in the MB's sockets, and a
> new front panel pcb that would also plug into a card-edge socket on the new
> motherboard, or

Putting aside card-edge for a minute (see above :-), what you suggest here is
called a backplane. It's been used in a few computers, and in other
equipment, both in instances where all connectors were the same, and all
signals were bussed (see the early Zenith Data Systems XT-class machines for
example) and in earlier stuff where each connector was different and you
could only plug one board in to one particular slot (see "Digital Group"
early pre-PC computers for an example of this). The biggest problem I see
with this is that you don't want all signals bussed because there are likely
to be different signals used on each board, and the other way means that any
changes makes for a redesign needed and difficulty in upgrades, etc. should
anything change in the future. Personally I'd avoid this.

> 5) card-edge sockets on all the pcbs, with small pcbs that plug into them,
> with discrete wires or ribbon cables soldered to the small pcbs (i.e.
> hand-made custom card-edge-connector cabling, hehehe...),

See above comments about card-edge connectors. This is also much more
labor-intensive assembly and more places for things to go wrong.

> 6) pcb-mount terminal blocks with discrete wires, or

<shrug>

Terminal blocks are okay and I'd go that way if I were dealing with wiring
that had to carry nontrivial levels of power (say more than a couple of
hundred mA or so) but for the most part you won't need it. Lots of potential
for error here, too.

> 7) something similar to #1, but with some as-yet-unknown (to me) connector
> and/or cabling types (I even considered pcb-mountable modular phone jacks
> and cabling).

Aside from a limited number of conductors these are reasonable, and fairly
cheap. Not terribly robust mechanically, but easy enough to crimp those
connectors on. Unless you need to start crossing wires, etc. They're
probably cheaper than pin connectors, but other than that I don't see that
much of an advantage to going with them.

> Which of those (probably out of #1 through #4) sound "good"?

One thing you might consider in terms of using pin connectors is the
possibility of using off-the-shelf cables, such as 34 wires ("IDE cable") or
50 wires ("SCSI cable"), etc.

> One immediate "problem" I can foresee, with just adding a second side to
> each pcb and then running traces (on the "new" side of each board) to pin
> headers: Our pcb-making process is rudimentary and does NOT include the
> ability to make plated-through holes. SO, to have headers that are
> connected to the new top side traces, while the connectors are also sitting
> on the top sides of the boards, I wouldn't be able to solder the top side's
> trace directly to the headers' pins, since the headers sit right on the
> boards. So I'd have to make an extra row of holes next to each header row,
> that could have pins inserted that could be soldered on both sides. (I was
> thinking I might just use a single-row header, upside down with the longer
> pins halfway into the holes. It might be "ugly". But it would also provide
> handy test-points...).

Test points are good. But you might also consider using a connector that has
way more pins than you need and using a bunch of them for grounds. This is
what's typically the case with a lot of PC internal interconnects, and it
makes for better performance in terms of crosstalk etc. between the wires.
Though I don't know how much of a problem that's likely to be in the
equipment you're talking about.

> Many of the switches in the unit just happen to use groups of six
> connections. So, for many on-board and board-to-board "jumpers", short
> lengths (six or eight inches max, probably) of 6-conductor ribbon cables
> might be handy, although, changing to double-sided boards might ("should")
> eliminate that need.

Smallest connector you'll probably find is 10 pins, I think, unless you get
the longer strips and cut them, but I'm not sure about the cable connectors.

> The primary GOAL is still to make the unit easier, faster, and cheaper to
> assemble. SO, I really don't want to use cabling schemes that require a lot
> of time or expensive equipment, to assemble (IDC?). Socketed connections
> are preferred, so that units can be easily disassembled for repairs or
> board-level upgrades. If ribbon cables are used, I would prefer having
> pre-assembled cables available.

See above comment on that. :-)

> I did buy a couple-hundred new IDE 40-pin cables (with three 2x20 sockets
> each), for $5! And I got several hundred 40-pin breakable gold-plated
> single-row pin headers for about $10. And I got 300 2.5-inch-long 36-wire
> ribbon cables that have 36-pin single-row sockets on both ends, for $30
> including shipping, and 200 36-pin single-row gold-plated headers for about
> $5 or $10. (Actually, I got the *300* of the new IDE cables, for $5.99 plus
> $21.42 s/h.)

There you go...

> SO, I may end up cutting the IDE cables so they have just two sockets with
> about 8 inches of cable between them, and using those. Or I may use the
> short 36-pin cables and single-row headers.
>
> However, I am ALREADY running into the problem of *possibly* not having
> enough ROOM on the new front-panel PCB, for that many large connectors. SO
> I *STILL* probably need to find something smaller (fewer conductors), for
> the two smaller boards to use, to connect to the front panel PCB, and/or to
> the other boards.

Hm.

> ANOTHER IDEA: If I could find a very large (and very cheap) surplus
> stockpile of ISA "RISER BOARDS" (or even 8-bit passive backplane boards, or
> somesuch) that have 5 or more slots, those could make PERFECT ready-made
> motherboards, to mount in the bottom of the case, with the slots parallel
> to the front panel. Then ALL of my boards could plug into the slots and all
> be connected together, including the front panel. Of course, I could make
> my own similar motherboard-type boards, fairly easily, with available
> card-edge connectors. (But the large, new card-edge-connectors are usually
> quite expensive. Maybe I can find a large surplus lot of them...) But MAYBE
> there's a really low-cost stockpile of something similar, somewhere, which
> would certainly make things MUCH easier and faster and cheaper.

I have a few of those riser cards on hand that I was hoping to find a use for
some time, and you're welcome to those, but I don't know about several
hundred. :-) I had a guy come by with a load of "computer junk" the other
day and declined to take the one Packard Bell machine that he had that was
one of those boxes, probably could've snagged another one, but...

> There are also several connections to the rear panel, usually with only one
> or two wires, that I need to worry about. I am thinking of using either
> one- and two-wire pin headers and sockets, for those, or small terminal
> blocks of some type. However, I still would LIKE to have all pre-assembled
> cables (i.e. sockets already on both ends of appropriate-length cabling.

For something like that I've seen some commercial gear that used different
styles of connectors (all 2-pin) so you couldn't mix them up and plug
something into the wrong place. You could also handle that issue by setting
the wire length to be only appropriate for where it's supposed to go and
similar tricks. Something to worry about, anyway.

> Peak currents in some of the signal conductors could reach 1.5 Amps.
> However, most of those waveforms are triangular or sawtooth, making the
> average (DC-equivalent) current only HALF of the peak value. But the main
> DC power supply rails MAY have to be connected from the separate power
> supply board to the other boards using discrete wiring that's screwed into
> terminal blocks, for that reason (max current-carrying capability).

Or at least something that's heavier-duty than pin connectors, though it's of
course possible to use several of those pins for this purpose.

The Osborne 1 computer had a weird custom board on their floppy drives, which
was A and which was B was determined only by where the terminator position.
This was before twists in cables and similar nonsense. They also ran the
power for those drives up through the ribbon cable, to a card-edge
connector. There were reliability problems with those over time...

> Sorry to have blathered-on for so long, here! If there's anything you can
> offer, I'm all ears!

Hopefully some of what I've kicked out here will be of some help. I see a
lot of different things being done in commercial gear manufactured over a
long period of time, from no connectors at all to a bunch of different
alternatives.

If I were building something I think I'd probably tend to favor pin connectors
for signals and something a little heavier for handling any kind of power,
maybe a "pin connector" that's larger (0.156 spacing?) and that uses the
square pins for a better contact.

> Thought I would mention...again...the possibility of using pin headers
> on the *edge* of the board. No need to drill holes or worry about
> soldering pins on both sides. Here's an illustration:
> http://macetech.com/edgeheader.jpg
>

> Pin headers are good reliable connectors, particularly if shrouded
> connectors
> are used, and if they're also using ejector levers there isn't much
> stress
> on the cabling.

> I think less well of card-edge connectors. You'll have problems with
> tarnish
> on the card, and lack of reliability eventually with the connectors over
> time. Notice that card-edge was the way to go with the old 5.25" and 8"
> floppy drives, and early hard drives as well. Nowadays _all_ 3.5"
> floppy
> drives and all IDE and SCSI hard drives use pin connectors. That should
> tell
> you something. :-)

> Thanks, to everyone who replied so far, for the good suggestions and
> information!
>
> This re-design is still in the very early stages. I don't know if this
> is too off-topic. But I'll post a sort of summary of the different
> board/connector options I'm considering (mostly copied from an email
> that I sent to a friend, recently, about this stuff). Maybe some of you
> can set me straight, or offer some practical tips, or some ideas.
>

> And I am sorry that I blathered-on, for so long, *AGAIN*. (This

>
> Cheers,
>
> Tom Gootee

> You make a good point, if I understood correctly, about using
> individually-pluggable wires, with a single-pin on the pcb for each
> one. I did read some posts in one of the pinball or arcade game
> newsgroups, or a website referenced there, about different types of
> connectors, where they were saying/claiming that crimp-type connectors
> for discrete wires are one of the most-reliable types (which includes
> wires with crimped-on pins that are then inserted/mounted into
> multi-connection sockets or plugs). They also claimed that soldering, in
> addition to crimping, is not necessary, and should probably even be
> avoided, since it might do some harm to the connector, or the
> wire/insulation, if not done perfectly.
>

> e.g. I also REALLY wanted to be able to see the whole "family" of
> curves, for a transistor, all at once, like on a "real" curve tracer. So
> I eventually figured out how to have a ramp "sweep" signal for the DUT,
> with a synchronized staircase signal for the base/gate.

> And I needed multiple voltage rails, so I designed a boost-mode
> switching power supply board that takes 12 vdc and makes the plus and
> minus 18 vdc (variable, actually) needed by most of the ICs (and at up
> to 3 amps, total), and the +5 for CMOS ICs.

> With all of that working, I decided I also needed to be able to "push
> some more amps" into the device under test (DUT). So I designed a power
> amplifier. And I wanted calibrated excitation-voltage levels for the DUT
> so I made the amp's gain switchable. Then I decided that the resistor
> networks required for switching the gain were kind of "ugly", so I
> designed a coool feedback control loop that sets the gain.

> I also added lots of other stuff, including instrumentation amplifiers
> to sense the voltage and current used for the x-y scope display, and
> inverters, buffers, and switching, etc, so I could display the current
> through ANY of the three DUT leads versus the voltage across ANY two of
> the DUT leads, and flip the displayed polarity of either of them at any
> time.

> And I added a range of frequencies for the sweep signal. And I added
> twelve selectable current-limiter resistances. And I added an option for
> a triangle waveform instead of a ramp, and an integrator to produce a
> quasi-sine waveform from the triangle. And so on and so on. And on and
> on and on...

On Friday 20 August 2004 03:41 pm, Thomas P. Gootee wrote:

> There are several possibilities that I have considered:
>
> 1) pin headers on each pcb, with ribbon cables running to similar headers
> on the front panel's new pcb, or

Pin headers are good reliable connectors, particularly if shrouded connectors
are used, and if they're also using ejector levers there isn't much stress
on the cabling.

> 2) card-edge connectors on the front panel pcb, along the bottom, that each
> of the three pcboards' edges could plug into, or

I think less well of card-edge connectors. You'll have problems with tarnish
on the card, and lack of reliability eventually with the connectors over
time. Notice that card-edge was the way to go with the old 5.25" and 8"
floppy drives, and early hard drives as well. Nowadays _all_ 3.5" floppy
drives and all IDE and SCSI hard drives use pin connectors. That should tell
you something. :-)

=== Point taken. But all of the PCs that I've seen still use card-edge connectors
=== for all of the CARDS, i.e. the PCBs, in the expansion slots (e.g. ISA,
=== EISA, PCI, etc). The "slots" are just card-edge connectors. I have
=== some that are over 15 years old that still work fine. Also, I check out
=== and/or service or refurbish a lot of old Tektronix and other test equipment,
=== much of which uses card-edge connectors (e.g. Tek 7000 series scope
=== plug-ins and Tek TM500-series plug-ins). And those are heavily used, i.e.
=== they typically undergo MANY mating/unmating cycles over their lifetimes.
=== Occasionally there is a mechanical alignment problem, or somesuch, that
=== causes problems. But not "too" many! And a lot of that stuff is at least 20 or
=== 30 years old. (Then again, maybe all of the mating/unmating cycles HELPED
=== keep the card-edge connectors in better shape (by scraping the surfaces).

> 3) right-angle headers or sockets on each pcb, that would plug directly
> into straight headers or sockets on the front panel pcb (pin headers and
> sockets, or DIN, or even D-Sub), with NO CABLING necessary, or

Pin headers at both ends of the connection is workable, provided you can
arrange the layout of stuff to accomodate this without too much trouble, but
it's gonna be a real hassle to design, compared to using cables.

=== Well, the boards are ALREADY sitting at right angles to the front panel,
=== with their edges just about in the right positions. And I guess the on-board
=== part of the re-design would be about the same as if I were using cables.
=== It seems like eliminating anything, especially %$#! cables, would be
=== "a *GOOD* thing".
===
=== But HEY! Couldn't I use the backplane/buss idea, but with pin headers and
=== sockets, instead of card-edge connectors? I just REALLY like the idea of
=== using PCBs instead of wires and cables!

> 4) another new board, a "motherboard", in the bottom of the enclosure, with
> card-edge sockets, along with a total redesign of the current boards'
> layouts, so they could be mounted vertically, in the MB's sockets, and a
> new front panel pcb that would also plug into a card-edge socket on the new
> motherboard, or

Putting aside card-edge for a minute (see above :-), what you suggest here is
called a backplane. It's been used in a few computers, and in other
equipment, both in instances where all connectors were the same, and all
signals were bussed (see the early Zenith Data Systems XT-class machines for
example) and in earlier stuff where each connector was different and you
could only plug one board in to one particular slot (see "Digital Group"
early pre-PC computers for an example of this). The biggest problem I see
with this is that you don't want all signals bussed because there are likely
to be different signals used on each board, and the other way means that any
changes makes for a redesign needed and difficulty in upgrades, etc. should
anything change in the future. Personally I'd avoid this.

=== Well, in general, you're probably right. But, in THIS case, I think it would
=== be great. Basically, the one main board and the new front panel board have
=== LOTS of things that they need to share, like multiple 2P6T switches' wiring, and
=== a 1P12T switch's wiring, and a couple of 4P3T switches' wiring, and various
=== other controls' wiring, plus signals in and out, etc, and, of course, the power
=== supply rails, and all of the separate ground paths, and probably some other stuff
=== that I'm forgetting to mention. Then there's the power amplifier board, which
=== only shares the wiring to one side of one of the same 2P6T switches, plus a
=== couple of i/o signal paths, and, of course, the power supply rails and some
=== ground paths. The third and last original board is just the power supply. And
=== all of the boards need to get power rails and separate ground paths, etc, from
=== the power supply board. I just can't see *anything* wrong with putting them all
=== on a nice big buss. Of course, the buss would have quite a few spare positions,
=== for future additions. I'd probably also have at least one spare board position,
=== for the same reason (just so I wouldn't have to change it, if another board was
=== ever added).
===
=== Am I missing something?? Or is my thinking wrong, about that, somehow??
===
=== I *DID* find some sources for fairly-inexpensive pcb-mount pin headers and
=== sockets, as well as pcb-mount card-edge connectors. So the cost of all of the
=== connectors, either pin-type or card-edge, for use on a parallel-buss pcb with
=== 62 or more traces, and six card positions (I would only *need* 5, assuming my
=== main board is split into two boards so it would fit vertically into the same cabinet,
=== which is only about 3 inches high, and assuming I added a new front panel pcb),
=== could be in a range as low as $10.00 (for 100 quantities), especially if I used
=== TWO headers and sockets that were each HALF the size I need for the main
=== board and the front
=== panel board, because then I could just use ONE of each for the two "little" boards.
===
=== (Of course, even $10 is a *significant* percentage-increase in the total parts cost
=== per unit. But, heck, I can see RIGHT OFF THE BAT that it would save WAY more
===than $10, in assembly labor costs alone (and *maybe* some in troubleshooting
=== labor, etc, too).
===
=== That would, technically, make it into two busses, I guess. But the "backplane"
=== board would be made so that the "extra" sockets could be added later, for the
=== other card positions, if it ever became necessary, without changing the
=== backplane board's layout.

> 5) card-edge sockets on all the pcbs, with small pcbs that plug into them,
> with discrete wires or ribbon cables soldered to the small pcbs (i.e.
> hand-made custom card-edge-connector cabling, hehehe...),

See above comments about card-edge connectors. This is also much more
labor-intensive assembly and more places for things to go wrong.

=== Yeah. That option was just mentioned "for the sake of completeness".

> 6) pcb-mount terminal blocks with discrete wires, or

<shrug>

Terminal blocks are okay and I'd go that way if I were dealing with wiring
that had to carry nontrivial levels of power (say more than a couple of
hundred mA or so) but for the most part you won't need it. Lots of potential
for error here, too.

=== Yes. The error potential is one of the main possible problems that I see
=== with using any kind of single-wire connections, socketed or not, although
=== if they're socketed/removable, the errors WOULD be much easier to correct,
=== assuming they could be found...
===
=== BUT, there ARE "non-trivial" levels of current, in a few places. The
=== power amplifier board has to be able to push up to 1.5 Amps, through the
=== front panel connectors and on to the device under test (DUT). And the
=== power supply board, obviously, has to supply that juice. In the current design,
=== those high-current signals also pass through the main curve tracer board,
=== so they can have their currents and voltages sensed and fed to the
=== instrumentation amplifiers, etc, that then produce the x-y outputs to the
=== scope display. But, with the new front panel PCB, *probably* only the
=== sensing-lines will need to go back to the main board.

> 7) something similar to #1, but with some as-yet-unknown (to me) connector
> and/or cabling types (I even considered pcb-mountable modular phone jacks
> and cabling).

Aside from a limited number of conductors these are reasonable, and fairly
cheap. Not terribly robust mechanically, but easy enough to crimp those
connectors on. Unless you need to start crossing wires, etc. They're
probably cheaper than pin connectors, but other than that I don't see that
much of an advantage to going with them.

=== Yes. Easy to crimp. And cheap. Might've been perfect as a cheap, easy
=== source for short 6-wire "jumpers". But, besides being a little "weird" in an
=== application like this one, it turns out that their connectors would just be
=== way too BIG to have any hope of fitting onto the boards, as they are now.

> Which of those (probably out of #1 through #4) sound "good"?

One thing you might consider in terms of using pin connectors is the
possibility of using off-the-shelf cables, such as 34 wires ("IDE cable") or
50 wires ("SCSI cable"), etc.

=== Definitely! See farther below.

> One immediate "problem" I can foresee, with just adding a second side to
> each pcb and then running traces (on the "new" side of each board) to pin
> headers: Our pcb-making process is rudimentary and does NOT include the
> ability to make plated-through holes. SO, to have headers that are
> connected to the new top side traces, while the connectors are also sitting
> on the top sides of the boards, I wouldn't be able to solder the top side's
> trace directly to the headers' pins, since the headers sit right on the
> boards. So I'd have to make an extra row of holes next to each header row,
> that could have pins inserted that could be soldered on both sides. (I was
> thinking I might just use a single-row header, upside down with the longer
> pins halfway into the holes. It might be "ugly". But it would also provide
> handy test-points...).

Test points are good. But you might also consider using a connector that has
way more pins than you need and using a bunch of them for grounds. This is
what's typically the case with a lot of PC internal interconnects, and it
makes for better performance in terms of crosstalk etc. between the wires.
Though I don't know how much of a problem that's likely to be in the
equipment you're talking about.

=== Good point. There ARE some signals for which I'm planning to do that.

> Many of the switches in the unit just happen to use groups of six
> connections. So, for many on-board and board-to-board "jumpers", short
> lengths (six or eight inches max, probably) of 6-conductor ribbon cables
> might be handy, although, changing to double-sided boards might ("should")
> eliminate that need.

Smallest connector you'll probably find is 10 pins, I think, unless you get
the longer strips and cut them, but I'm not sure about the cable connectors.

=== Actually, many/most of the pin headers go down to 2 pins, I think.

> The primary GOAL is still to make the unit easier, faster, and cheaper to
> assemble. SO, I really don't want to use cabling schemes that require a lot
> of time or expensive equipment, to assemble (IDC?). Socketed connections
> are preferred, so that units can be easily disassembled for repairs or
> board-level upgrades. If ribbon cables are used, I would prefer having
> pre-assembled cables available.

See above comment on that. :-)

=== Yup!

> I did buy a couple-hundred new IDE 40-pin cables (with three 2x20 sockets
> each), for $5! And I got several hundred 40-pin breakable gold-plated
> single-row pin headers for about $10. And I got 300 2.5-inch-long 36-wire
> ribbon cables that have 36-pin single-row sockets on both ends, for $30
> including shipping, and 200 36-pin single-row gold-plated headers for about
> $5 or $10. (Actually, I got the *300* of the new IDE cables, for $5.99 plus
> $21.42 s/h.)

There you go...

=== Ebay can be good for that, as can the military surplus auctions. But I
=== ALWAYS run into TWO HUGE problems, doing it that way: 1) It takes
=== WAY too much time, just to FIND exactly the stuff I need, and even
=== more time to find a large lot that's "a steal". And, 2) It's a nightmare,
=== as far as having a reliable, i.e. repeatable source of supply.
===
=== I've also seen some stuff that looks like it would be PERFECT, that was
=== in fairly large qtys, and was VERY cheap. But it's stuff that I've
=== NEVER seen anywhere else. So I definitely don't want to design it in...

> SO, I may end up cutting the IDE cables so they have just two sockets with
> about 8 inches of cable between them, and using those. Or I may use the
> short 36-pin cables and single-row headers.
>
> However, I am ALREADY running into the problem of *possibly* not having
> enough ROOM on the new front-panel PCB, for that many large connectors. SO
> I *STILL* probably need to find something smaller (fewer conductors), for
> the two smaller boards to use, to connect to the front panel PCB, and/or to
> the other boards.

Hm.

> ANOTHER IDEA: If I could find a very large (and very cheap) surplus
> stockpile of ISA "RISER BOARDS" (or even 8-bit passive backplane boards, or
> somesuch) that have 5 or more slots, those could make PERFECT ready-made
> motherboards, to mount in the bottom of the case, with the slots parallel
> to the front panel. Then ALL of my boards could plug into the slots and all
> be connected together, including the front panel. Of course, I could make
> my own similar motherboard-type boards, fairly easily, with available
> card-edge connectors. (But the large, new card-edge-connectors are usually
> quite expensive. Maybe I can find a large surplus lot of them...) But MAYBE
> there's a really low-cost stockpile of something similar, somewhere, which
> would certainly make things MUCH easier and faster and cheaper.

I have a few of those riser cards on hand that I was hoping to find a use for
some time, and you're welcome to those, but I don't know about several
hundred. :-) I had a guy come by with a load of "computer junk" the other
day and declined to take the one Packard Bell machine that he had that was
one of those boxes, probably could've snagged another one, but...

=== Thanks for the offer. I just don't want to "design in" something that I
=== am not certain of having a large, fairly-reliable supply of. I could probably
=== very-easily buy a few thousand identical PCs, from a military
=== surplus auction or two, probably for about $1000 to $1500 for each semi
=== trailer load, which is what I used to see them go for, all the time. But,
=== just having to go through the buying and transporting and storing and
=== removing what I wanted and disposing of the rest would almost certainly
=== make it uneconomical, not to mention "WAY too much work". (It might
=== be different if I could find a decent way to use the whole case, and the
=== power supply, AND the motherboard slots, ALL left INTACT, where I
=== could just plug in my boards and mount my front panel stuff
=== somewhere... Hmm.... Whacky. But maybe for some other product!)

> There are also several connections to the rear panel, usually with only one
> or two wires, that I need to worry about. I am thinking of using either
> one- and two-wire pin headers and sockets, for those, or small terminal
> blocks of some type. However, I still would LIKE to have all pre-assembled
> cables (i.e. sockets already on both ends of appropriate-length cabling.

For something like that I've seen some commercial gear that used different
styles of connectors (all 2-pin) so you couldn't mix them up and plug
something into the wrong place. You could also handle that issue by setting
the wire length to be only appropriate for where it's supposed to go and
similar tricks. Something to worry about, anyway.

=== Another very good idea. Noted!

> Peak currents in some of the signal conductors could reach 1.5 Amps.
> However, most of those waveforms are triangular or sawtooth, making the
> average (DC-equivalent) current only HALF of the peak value. But the main
> DC power supply rails MAY have to be connected from the separate power
> supply board to the other boards using discrete wiring that's screwed into
> terminal blocks, for that reason (max current-carrying capability).

Or at least something that's heavier-duty than pin connectors, though it's of
course possible to use several of those pins for this purpose.

=== Even the low-cost pin headers from jameco.com are rated at 1 amp per
=== pin. In this case, the 1.5 amps is the PEAK. But it's for ramp-type
=== waveforms. So the average "DC-equivalent" current would only be HALF
=== of the 1.5 Amps. And yes, the power supply rails (and grounds) for
=== each board were going to be kept separate, anyway. And, as you said,
=== I could always run them doubled (or more), for any high-current ones.

The Osborne 1 computer had a weird custom board on their floppy drives, which
was A and which was B was determined only by where the terminator position.
This was before twists in cables and similar nonsense. They also ran the
power for those drives up through the ribbon cable, to a card-edge
connector. There were reliability problems with those over time...

=== Is it possible that the newer card-edge connectors are better, now?
=== Well, never mind. Wherever I would have wanted to use card-edge, I
=== can use pin headers and sockets, instead.

> Sorry to have blathered-on for so long, here! If there's anything you can
> offer, I'm all ears!

Hopefully some of what I've kicked out here will be of some help. I see a
lot of different things being done in commercial gear manufactured over a
long period of time, from no connectors at all to a bunch of different
alternatives.

=== YES. **QUITE** helpful. Some great ideas, and stored wisdom! And
=== usually it also helps just to hash through it, with someone else, anyway.
===
=== I DEEPLY appreciate your taking the time and energy to respond,
=== so well, and your willingness to share your knowledge and experience.

If I were building something I think I'd probably tend to favor pin connectors
for signals and something a little heavier for handling any kind of power,
maybe a "pin connector" that's larger (0.156 spacing?) and that uses the
square pins for a better contact.

===
=== Sounds right. I might even use the PC disk-drive-type power cables,
=== for the heavier stuff. (I just missed a chance to get a lot of something like
=== 500 brand new "Y"/splitter PC disk-drive power supply cables, on ebay,
=== that went for something like $10, total...! Those could have connected
=== all three of the boards... :-o )
===
=== Thanks again, *so* much! You, and the others on this wonderful group,
=== are truly great. If there's EVER anything that *I* can do, to help (any
=== of) YOU, please, just ASK!!
===
=== Highest regards,
===
=== Tom
===
=== Thomas P. (Tom) Gootee
=== tomg(AT)fullnet.com
=== http://www.fullnet.com/u/tomg
=== Jasper, Indiana, USA
===
===-------------------------------------



[Non-text portions of this message have been removed]

On Sunday 22 August 2004 10:04 am, Thomas P. Gootee wrote:

> > There are also several connections to the rear panel, usually with only
> > one or two wires, that I need to worry about. I am thinking of using
> > either one- and two-wire pin headers and sockets, for those, or small
> > terminal blocks of some type. However, I still would LIKE to have all
> > pre-assembled cables (i.e. sockets already on both ends of
> > appropriate-length cabling.

> For something like that I've seen some commercial gear that used different
> styles of connectors (all 2-pin) so you couldn't mix them up and plug
> something into the wrong place. You could also handle that issue by
> setting the wire length to be only appropriate for where it's supposed to
> go and similar tricks. Something to worry about, anyway.
>
> === Another very good idea. Noted!

This would also probably involve making a "harness" for the wiring, which may
make things a bit more labor-intensive, and may also prove to be a
disadvantage when it comes to bundling stuff together that really shouldn't
be. I can't speak more to that without knowing more about what sort of
signals are running around in that equipment...

<...>

> The Osborne 1 computer had a weird custom board on their floppy drives,
> which was A and which was B was determined only by where the terminator
> position. This was before twists in cables and similar nonsense. They also
> ran the power for those drives up through the ribbon cable, to a card-edge
> connector. There were reliability problems with those over time...
>
> === Is it possible that the newer card-edge connectors are better, now?

No doubt they are, at least once things progressed beyond ISA slots. I have
heard of some ISA connectors giving trouble, and even encountered that
*once* that I can recall (one of my XT-class MBs has a bit of black tape over
one slot :-), but have never heard of this being the case with PCI and AGP
slots, which use a different style of connector and a lot more pins.

<...>

> > If I were building something I think I'd probably tend to favor pin
> > connectors for signals and something a little heavier for handling any
> > kind of power, maybe a "pin connector" that's larger (0.156 spacing?) and
> > that uses the square pins for a better contact.

> Sounds right. I might even use the PC disk-drive-type power cables, for the
> heavier stuff. (I just missed a chance to get a lot of something like 500
> brand new "Y"/splitter PC disk-drive power supply cables, on ebay, that went
> for something like $10, total...! Those could have connected all three of
> the boards... :-o )

Now *those* have had their share of problems too. Like the common Molex
connectors, reliability leaves something to be desired when you're looking
at a female contact which consists of a bit of sheet metal that's going
around a pin, I don't know if this is a matter of what material is used for
the contact or not. There have been a few instances where I've had to take a
small tool of some sort and close them up a bit, after they'd opened up
some...

The same is going to be true to some extent for DB-xx connectors, though
they're better at it as the positioning and size of the male pins seems to be
more tightly controlled.

My preference for high reliability is contacts that have a "wiping" action,
which can be seen in the "Centronics" style connectors used on the back of a
printer, which I've also seen in sizes of 24 and 50 pins and there are
probably others. Some "external" connections on SCSI cards seem to offer a
miniature version of this, like on my Adaptec 2940uw, and the SCSI-wide
connector is similar in a 68-pin version as well. Some of the pin connectors
I've seen/used over the years are based on a similar idea, though I don't
have part numbers handy. The one half is a square pin (though sometimes
round ones are used too), and the other half is a bit of sheet metal that's
"folded" several times (think of an "@" character :-) and has some continuous
spring pressure holding it up against the other half. This is in sharp
contrast to a bit of sheet metal that's supposed to wrap itself around a pin.

>"Thomas P. Gootee" <tomg@f...> wrote:
>Thanks for the thoughtful reply.

>discrete wires are one of the most-reliable types (which includes
>wires with crimped-on pins that are then inserted/mounted into multi-
>connection sockets or plugs). They also claimed that soldering, in
>addition to crimping, is not necessary, and should probably even be
>avoided, since it might do some harm to the connector, or the
>wire/insulation, if not done perfectly.<snip>

>So, *eventually*, I thought to myself, "Hey! OTHER people might like
>to have one of these, TOO!". Of course, when a hobbyist designs and
>builds a piece of electronic equipment, especially if it's
>essentially the first time they've done a large self-designed
>project, then when it's all "finished", and works "perfectly",
>they've still maybe done only about **5%** of the work that's needed
>to make it into an actual "commercial product".
>
>Mine's also available in KIT form, which makes it even MORE work, in
>some ways, since I have to produce (AND keep *updated*) all of the
>construction diagrams, for component placement, wiring, mechanical
>stuff, etc, and assembly and alignment instructions, plus complete
>schematics, detailed parts lists, instrument-panels' artwork, etc
>etc. (all in "presentable" forms). And I have to do all of the
>sourcing and supplier stuff, keep a large parts and supplies
>inventory, make circuit boards, make apply-able instrument panel
>artwork, count parts and supplies into nice little multi-
>compartmented plastic kit-boxes, market and sell them, pack and ship
>them, support them, etc etc etc. I'm also working on a "real"
>ops/service manual, which, eventually, is intended to be as good as
>the legendary older Tektronix manuals. (Hmmm... Maybe I *AM*
>crazy... Hehe...)
>
>And I still have MANY, many things that I'd like to add, and change,
>in the Curve Tracer product. But, first, I want to "clean up" the
>current version, especially since I may eventually have it (or parts
>of it) mass-produced, maybe by a third party. I've also got some
>other great electronic products "in the pipeline". But I think that
>I need to "get to the next level", first, so I can hire some people,
>to hopefully allow ME to spend my time on things where I can
>contribute the most, i.e. where any specialized abilities that I
>have might make the most difference, instead of on things that
>almost anyone could be doing. I've been trying to "bootstrap" this
>business, starting with not much capital. But I may end up having to
>take on some investors, to be able to get where I want to be
>(quickly-enough, anyway).

>And I am sorry that I blathered-on, for so long, *AGAIN*. (This
>business has basically "taken over my life", as you can probably
>tell, hehe. But it IS *quite* enjoyable...)

>CyberMace wrote:
>I'm curious about how well you homegrown gadget-builders do. I have
>quite a few ideas of my own sitting on the shelf, and have never been
>able to get anyone to tell me how well their business actually does.
>I don't want actual numbers, but basically there are three possible
>ranges: 1. If I counted the effort I put in on these, I'm losing
>money. 2. I'm breaking even or making a reasonable profit, not enough
>to quit my day job but still worth it. 3. This is going so well that
>I quit my day job and am concentrating on expanding my product line.
>
>I just need to know what kind of a market is out there, I have no
>idea how many people own soldering irons and are interested in
>building kits.

> > And I am sorry that I blathered-on, for so long, *AGAIN*. (This
> business has basically "taken over my life", as you can probably

> hehe. But it IS *quite* enjoyable...)
> >
> > Cheers,
> >
> > Tom Gootee
>
>
> I'm curious about how well you homegrown gadget-builders do. I have
> quite a few ideas of my own sitting on the shelf, and have never

> able to get anyone to tell me how well their business actually

> don't want actual numbers, but basically there are three possible
> ranges: 1. If I counted the effort I put in on these, I'm losing
> money. 2. I'm breaking even or making a reasonable profit, not

> to quit my day job but still worth it. 3. This is going so well

> quit my day job and am concentrating on expanding my product line.
>
> I just need to know what kind of a market is out there, I have no

> how many people own soldering irons and are interested in building

> === Roy,
>
> === THANKS for the excellent reply!
>
> === MY current responses are intermingled, BELOW, and marked

>
> === - Tom Gootee
>
>
> Date: Fri, 20 Aug 2004 16:25:24 -0400
> From: "Roy J. Tellason" <rtellason@b...>
> Subject: Re: RE: making vias (was: Re: Plating thruholes.)
>
> I'm just gonna toss out a few thoughts coming to the fore, based

> working on all sorts of stuff over several decades, mostly

>
> === Great! "Repairs" usually tell the true tale...
>
> On Friday 20 August 2004 03:41 pm, Thomas P. Gootee wrote:
>
> > There are several possibilities that I have considered:
> >
> > 1) pin headers on each pcb, with ribbon cables running to similar

> > on the front panel's new pcb, or
>
> Pin headers are good reliable connectors, particularly if shrouded

> are used, and if they're also using ejector levers there isn't

> on the cabling.
>
> > 2) card-edge connectors on the front panel pcb, along the bottom,

> > of the three pcboards' edges could plug into, or
>
> I think less well of card-edge connectors. You'll have problems

> on the card, and lack of reliability eventually with the

> time. Notice that card-edge was the way to go with the old 5.25"

> floppy drives, and early hard drives as well. Nowadays _all_ 3.5"

> drives and all IDE and SCSI hard drives use pin connectors. That

> you something. :-)
>
> === Point taken. But all of the PCs that I've seen still use card-

> === for all of the CARDS, i.e. the PCBs, in the expansion slots

> === EISA, PCI, etc). The "slots" are just card-edge connectors. I

> === some that are over 15 years old that still work fine. Also, I

> === and/or service or refurbish a lot of old Tektronix and other

> === much of which uses card-edge connectors (e.g. Tek 7000 series

> === plug-ins and Tek TM500-series plug-ins). And those are heavily

> === they typically undergo MANY mating/unmating cycles over their

> === Occasionally there is a mechanical alignment problem, or

> === causes problems. But not "too" many! And a lot of that stuff

> === 30 years old. (Then again, maybe all of the mating/unmating

> === keep the card-edge connectors in better shape (by scraping the

>
> > 3) right-angle headers or sockets on each pcb, that would plug

> > into straight headers or sockets on the front panel pcb (pin

> > sockets, or DIN, or even D-Sub), with NO CABLING necessary, or
>
> Pin headers at both ends of the connection is workable, provided

> arrange the layout of stuff to accomodate this without too much

> it's gonna be a real hassle to design, compared to using cables.
>
> === Well, the boards are ALREADY sitting at right angles to the

> === with their edges just about in the right positions. And I

> === part of the re-design would be about the same as if I were

> === It seems like eliminating anything, especially %$#! cables,

> === "a *GOOD* thing".
> ===
> === But HEY! Couldn't I use the backplane/buss idea, but with pin

> === sockets, instead of card-edge connectors? I just REALLY like

> === using PCBs instead of wires and cables!
>
> > 4) another new board, a "motherboard", in the bottom of the

> > card-edge sockets, along with a total redesign of the current

> > layouts, so they could be mounted vertically, in the MB's

> > new front panel pcb that would also plug into a card-edge socket

> > motherboard, or
>
> Putting aside card-edge for a minute (see above :-), what you

> called a backplane. It's been used in a few computers, and in

> equipment, both in instances where all connectors were the same,

> signals were bussed (see the early Zenith Data Systems XT-class

> example) and in earlier stuff where each connector was different

> could only plug one board in to one particular slot (see "Digital

> early pre-PC computers for an example of this). The biggest

> with this is that you don't want all signals bussed because there

> to be different signals used on each board, and the other way

> changes makes for a redesign needed and difficulty in upgrades,

> anything change in the future. Personally I'd avoid this.
>
> === Well, in general, you're probably right. But, in THIS case, I

> === be great. Basically, the one main board and the new front

> === LOTS of things that they need to share, like multiple 2P6T

> === a 1P12T switch's wiring, and a couple of 4P3T switches' wiring,

> === other controls' wiring, plus signals in and out, etc, and, of

> === supply rails, and all of the separate ground paths, and

> === that I'm forgetting to mention. Then there's the power

> === only shares the wiring to one side of one of the same 2P6T

> === couple of i/o signal paths, and, of course, the power supply

> === ground paths. The third and last original board is just the

> === all of the boards need to get power rails and separate ground

> === the power supply board. I just can't see *anything* wrong with

> === on a nice big buss. Of course, the buss would have quite a few

> === for future additions. I'd probably also have at least one

> === for the same reason (just so I wouldn't have to change it, if

> === ever added).
> ===
> === Am I missing something?? Or is my thinking wrong, about that,

> ===
> === I *DID* find some sources for fairly-inexpensive pcb-mount pin

> === sockets, as well as pcb-mount card-edge connectors. So the cost

> === connectors, either pin-type or card-edge, for use on a parallel-

> === 62 or more traces, and six card positions (I would only *need*

> === main board is split into two boards so it would fit vertically

> === which is only about 3 inches high, and assuming I added a new

> === could be in a range as low as $10.00 (for 100 quantities),

> === TWO headers and sockets that were each HALF the size I need for

> === board and the front
> === panel board, because then I could just use ONE of each for the

> ===
> === (Of course, even $10 is a *significant* percentage-increase in

> === per unit. But, heck, I can see RIGHT OFF THE BAT that it would

> ===than $10, in assembly labor costs alone (and *maybe* some in

> === labor, etc, too).
> ===
> === That would, technically, make it into two busses, I guess. But

> === board would be made so that the "extra" sockets could be added

> === other card positions, if it ever became necessary, without

> === backplane board's layout.
>
> > 5) card-edge sockets on all the pcbs, with small pcbs that plug

> > with discrete wires or ribbon cables soldered to the small pcbs

> > hand-made custom card-edge-connector cabling, hehehe...),
>
> See above comments about card-edge connectors. This is also much

> labor-intensive assembly and more places for things to go wrong.
>
> === Yeah. That option was just mentioned "for the sake of

>
> > 6) pcb-mount terminal blocks with discrete wires, or
>
> <shrug>
>
> Terminal blocks are okay and I'd go that way if I were dealing with

> that had to carry nontrivial levels of power (say more than a

> hundred mA or so) but for the most part you won't need it. Lots of

> for error here, too.
>
> === Yes. The error potential is one of the main possible problems

> === with using any kind of single-wire connections, socketed or

> === if they're socketed/removable, the errors WOULD be much easier

> === assuming they could be found...
> ===
> === BUT, there ARE "non-trivial" levels of current, in a few

> === power amplifier board has to be able to push up to 1.5 Amps,

> === front panel connectors and on to the device under test (DUT).

> === power supply board, obviously, has to supply that juice. In the

> === those high-current signals also pass through the main curve

> === so they can have their currents and voltages sensed and fed to

> === instrumentation amplifiers, etc, that then produce the x-y

> === scope display. But, with the new front panel PCB, *probably*

> === sensing-lines will need to go back to the main board.
>
> > 7) something similar to #1, but with some as-yet-unknown (to me)

> > and/or cabling types (I even considered pcb-mountable modular

> > and cabling).
>
> Aside from a limited number of conductors these are reasonable,

> cheap. Not terribly robust mechanically, but easy enough to crimp

> connectors on. Unless you need to start crossing wires, etc.

> probably cheaper than pin connectors, but other than that I don't

> much of an advantage to going with them.
>
> === Yes. Easy to crimp. And cheap. Might've been perfect as a

> === source for short 6-wire "jumpers". But, besides being a

> === application like this one, it turns out that their connectors

> === way too BIG to have any hope of fitting onto the boards, as

>
> > Which of those (probably out of #1 through #4) sound "good"?
>
> One thing you might consider in terms of using pin connectors is

> possibility of using off-the-shelf cables, such as 34 wires ("IDE

> 50 wires ("SCSI cable"), etc.
>
> === Definitely! See farther below.
>
> > One immediate "problem" I can foresee, with just adding a second

> > each pcb and then running traces (on the "new" side of each

> > headers: Our pcb-making process is rudimentary and does NOT

> > ability to make plated-through holes. SO, to have headers that are
> > connected to the new top side traces, while the connectors are

> > on the top sides of the boards, I wouldn't be able to solder the

> > trace directly to the headers' pins, since the headers sit right

> > boards. So I'd have to make an extra row of holes next to each

> > that could have pins inserted that could be soldered on both

> > thinking I might just use a single-row header, upside down with

> > pins halfway into the holes. It might be "ugly". But it would

> > handy test-points...).
>
> Test points are good. But you might also consider using a

> way more pins than you need and using a bunch of them for grounds.

> what's typically the case with a lot of PC internal interconnects,

> makes for better performance in terms of crosstalk etc. between the

> Though I don't know how much of a problem that's likely to be in

> equipment you're talking about.
>
> === Good point. There ARE some signals for which I'm planning to

>
> > Many of the switches in the unit just happen to use groups of six
> > connections. So, for many on-board and board-to-board "jumpers",

> > lengths (six or eight inches max, probably) of 6-conductor ribbon

> > might be handy, although, changing to double-sided boards might

> > eliminate that need.
>
> Smallest connector you'll probably find is 10 pins, I think,

> the longer strips and cut them, but I'm not sure about the cable

>
> === Actually, many/most of the pin headers go down to 2 pins, I

>
> > The primary GOAL is still to make the unit easier, faster, and

> > assemble. SO, I really don't want to use cabling schemes that

> > of time or expensive equipment, to assemble (IDC?). Socketed

> > are preferred, so that units can be easily disassembled for

> > board-level upgrades. If ribbon cables are used, I would prefer

> > pre-assembled cables available.
>
> See above comment on that. :-)
>
> === Yup!
>
> > I did buy a couple-hundred new IDE 40-pin cables (with three 2x20

> > each), for $5! And I got several hundred 40-pin breakable gold-

> > single-row pin headers for about $10. And I got 300 2.5-inch-long

> > ribbon cables that have 36-pin single-row sockets on both ends,

> > including shipping, and 200 36-pin single-row gold-plated headers

> > $5 or $10. (Actually, I got the *300* of the new IDE cables, for

> > $21.42 s/h.)
>
> There you go...
>
> === Ebay can be good for that, as can the military surplus

> === ALWAYS run into TWO HUGE problems, doing it that way: 1) It

> === WAY too much time, just to FIND exactly the stuff I need, and

> === more time to find a large lot that's "a steal". And, 2) It's a

> === as far as having a reliable, i.e. repeatable source of supply.
> ===
> === I've also seen some stuff that looks like it would be PERFECT,

> === in fairly large qtys, and was VERY cheap. But it's stuff that

> === NEVER seen anywhere else. So I definitely don't want to design

>
> > SO, I may end up cutting the IDE cables so they have just two

> > about 8 inches of cable between them, and using those. Or I may

> > short 36-pin cables and single-row headers.
> >
> > However, I am ALREADY running into the problem of *possibly* not

> > enough ROOM on the new front-panel PCB, for that many large

> > I *STILL* probably need to find something smaller (fewer

> > the two smaller boards to use, to connect to the front panel PCB,

> > the other boards.
>
> Hm.
>
> > ANOTHER IDEA: If I could find a very large (and very cheap)

> > stockpile of ISA "RISER BOARDS" (or even 8-bit passive backplane

> > somesuch) that have 5 or more slots, those could make PERFECT

> > motherboards, to mount in the bottom of the case, with the slots

> > to the front panel. Then ALL of my boards could plug into the

> > be connected together, including the front panel. Of course, I

> > my own similar motherboard-type boards, fairly easily, with

> > card-edge connectors. (But the large, new card-edge-connectors

> > quite expensive. Maybe I can find a large surplus lot of them...)

> > there's a really low-cost stockpile of something similar,

> > would certainly make things MUCH easier and faster and cheaper.
>
> I have a few of those riser cards on hand that I was hoping to find

> some time, and you're welcome to those, but I don't know about

> hundred. :-) I had a guy come by with a load of "computer junk"

> day and declined to take the one Packard Bell machine that he had

> one of those boxes, probably could've snagged another one, but...
>
> === Thanks for the offer. I just don't want to "design in"

> === am not certain of having a large, fairly-reliable supply of. I

> === very-easily buy a few thousand identical PCs, from a military
> === surplus auction or two, probably for about $1000 to $1500 for

> === trailer load, which is what I used to see them go for, all the

> === just having to go through the buying and transporting and

> === removing what I wanted and disposing of the rest would almost

> === make it uneconomical, not to mention "WAY too much work". (It

> === be different if I could find a decent way to use the whole

> === power supply, AND the motherboard slots, ALL left INTACT, where

> === could just plug in my boards and mount my front panel stuff
> === somewhere... Hmm.... Whacky. But maybe for some other

>
> > There are also several connections to the rear panel, usually

> > or two wires, that I need to worry about. I am thinking of using

> > one- and two-wire pin headers and sockets, for those, or small

> > blocks of some type. However, I still would LIKE to have all pre-

> > cables (i.e. sockets already on both ends of appropriate-length

>
> For something like that I've seen some commercial gear that used

> styles of connectors (all 2-pin) so you couldn't mix them up and

> something into the wrong place. You could also handle that issue

> the wire length to be only appropriate for where it's supposed to

> similar tricks. Something to worry about, anyway.
>
> === Another very good idea. Noted!
>
> > Peak currents in some of the signal conductors could reach 1.5

> > However, most of those waveforms are triangular or sawtooth,

> > average (DC-equivalent) current only HALF of the peak value. But

> > DC power supply rails MAY have to be connected from the separate

> > supply board to the other boards using discrete wiring that's

> > terminal blocks, for that reason (max current-carrying

>
> Or at least something that's heavier-duty than pin connectors,

> course possible to use several of those pins for this purpose.
>
> === Even the low-cost pin headers from jameco.com are rated at 1

> === pin. In this case, the 1.5 amps is the PEAK. But it's for ramp-

> === waveforms. So the average "DC-equivalent" current would only be

> === of the 1.5 Amps. And yes, the power supply rails (and grounds)

> === each board were going to be kept separate, anyway. And, as you

> === I could always run them doubled (or more), for any high-current

>
> The Osborne 1 computer had a weird custom board on their floppy

> was A and which was B was determined only by where the terminator

> This was before twists in cables and similar nonsense. They also

> power for those drives up through the ribbon cable, to a card-edge
> connector. There were reliability problems with those over time...
>
> === Is it possible that the newer card-edge connectors are better,

> === Well, never mind. Wherever I would have wanted to use card-

> === can use pin headers and sockets, instead.
>
> > Sorry to have blathered-on for so long, here! If there's

> > offer, I'm all ears!
>
> Hopefully some of what I've kicked out here will be of some help.

> lot of different things being done in commercial gear manufactured

> long period of time, from no connectors at all to a bunch of

> alternatives.
>
> === YES. **QUITE** helpful. Some great ideas, and stored wisdom!

> === usually it also helps just to hash through it, with someone

> ===
> === I DEEPLY appreciate your taking the time and energy to respond,
> === so well, and your willingness to share your knowledge and

>
> If I were building something I think I'd probably tend to favor pin

> for signals and something a little heavier for handling any kind of

> maybe a "pin connector" that's larger (0.156 spacing?) and that

> square pins for a better contact.
>
> ===
> === Sounds right. I might even use the PC disk-drive-type power

> === for the heavier stuff. (I just missed a chance to get a lot of

> === 500 brand new "Y"/splitter PC disk-drive power supply cables,

> === that went for something like $10, total...! Those could have

> === all three of the boards... :-o )
> ===
> === Thanks again, *so* much! You, and the others on this wonderful

> === are truly great. If there's EVER anything that *I* can do, to

> === of) YOU, please, just ASK!!
> ===
> === Highest regards,
> ===
> === Tom
> ===
> === Thomas P. (Tom) Gootee
> === tomg(AT)fullnet.com
> === http://www.fullnet.com/u/tomg
> === Jasper, Indiana, USA
> ===
> ===-------------------------------------
>
>
>
> [Non-text portions of this message have been removed]

>Still 500 bucks to those in THIS group, who express interest before
>month's end. And you WILL "see it" before month's end.

> OK. Yeah. The Molex "K.K." series has that type of pins.

> They are basically flat springs, which come down from the wire/crimp end of
> the pin, bend about 135 degrees at the bottom, and go about 4 mm before
> bending back toward the rest of the pin at something less than 180 degrees,
> and continuing back to the vertical part of the pin, where they actually
> have a tab that goes THROUGH a small slot in the pin and then is bent, to
> retain it in the slot.

> No time for more, right now. But thanks for all of your other comments,
> too!

>Still 500 bucks to those in THIS group, who express interest before
>month's end. And you WILL "see it" before month's end.

> >Still 500 bucks to those in THIS group, who express interest before
> >month's end. And you WILL "see it" before month's end.
>
> Expressing interest, expressing interest! :-)
>
> -Johnathan

> (gasp!)
>
> just MOVE the whole main board ONTO the new front panel PCB?!!
>

> And you WILL "see it" before month's end.