MOTM

klem_klemmingberg@... writes:

>>I too have been a victim of overzealous coax soldering-- hoist on my own 
petard, as it were.  A suggestion for Paul S. that might save him & future 
kit builders a bit of hassle is to add a little blurb in the toubleshooting 
sections of the module manuals advising builders to make sure none of their 
coax cables are shorted.<<

I've had a different problem.  Those damn switches don't seem to like the 
heat of a soldering iron.  I noticed on a number of occasions after soldering 
leads to a switch and then flipping the switch up and down, it didn't make a 
positive clicking feel in one of the directions.  Checking continuity even 
confirmed that the switches weren't working right.  I would have to flip the 
switch on and off a whole bunch of times before it would self correct.  One 
switch I was sure I would have to replace but after about 100 toggles it 
finally fixed itself.  I don't know what's going on internally, but I now be 
careful to solder them as fast a possible and get the hell out of there.

-Elhardt

In a message dated 2/22/2001 3:16:23 PM, elhardt@... writes:

>Those damn switches don't seem to like the 
>heat of a soldering iron.

Wasn't it you that was having trouble with a soldering iron continually 
burning out tips maybe a year ago? Maybe this problem is related to that 
(over voltage or something similar).

JB

--- elhardt@... wrote:
> klem_klemmingberg@... writes:
> 
> >>I too have been a victim of overzealous coax
> soldering-- 
> 
> I've had a different problem.  Those damn switches
> don't seem to like the heat of a soldering iron.  I
> noticed on a number of occasions after soldering 
> leads to a switch and then flipping the switch up
> and down, it didn't make a positive clicking feel in
> one of the directions... 
> 
> -Elhardt
> 
-----------------------------------------------------

I, too have had trouble with coax and switch contacts
alike.  I've found that *Preparation* is the key...

With coax, I strip and tin each coax lead, twisting
the shield braid into a lead, and adding a short
pigtail to fit the PC hole if necessary. I'll use the
stronger outer braid to hold the cable to the board,
then solder the inner conductor.  It's made much
easier if the pads to be soldered to are tinned, as
well; this minimizes the need for heat, and cold
solder joints.

For switches, I get out the X-Acto (hobby) knife, and
scrape the oxidation from the solder lugs - gently,
until they're shiny again.  Then, a quick tinning of
the lugs.  The resultant solder joint will easily hold
the wire and lug together without a great deal of
heat, and will produce a nice, shiny fillet.  Works
great with potentiometer lugs/pins, too!

As a side note, I usually tin the IC pads on my
boards, as well.  Even when just inserting sockets
(which, as I'm sure you know, are also
heat-sensitive), it makes a nice, clean joint, and
helps to avoid solder bridges between pads.

Hope someone finds this useful!

     Dave Garfield, "Professional Lurker"
                     and HUGE Analog fan!


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Wow, it's pretty hard to melt switches. It almost sounds like your iron is 
not hot enough and / or does not have enough mass to heat the connection 
and the solder quickly.  This will cause you to have to leave the iron on 
the connection too long in order to melt the solder, and you will overheat 
the switch or any other part.  700 F is a good temp for the iron.

-dave-

At 06:13 PM 2/22/01 -0500, you wrote:

>I've had a different problem.  Those damn switches don't seem to like the
>heat of a soldering iron.  I noticed on a number of occasions after soldering
>leads to a switch and then flipping the switch up and down, it didn't make a
>positive clicking feel in one of the directions.  Checking continuity even
>confirmed that the switches weren't working right.  I would have to flip the
>switch on and off a whole bunch of times before it would self correct.  One
>switch I was sure I would have to replace but after about 100 toggles it
>finally fixed itself.  I don't know what's going on internally, but I now be
>careful to solder them as fast a possible and get the hell out of there.

>With coax, I strip and tin each coax lead, twisting
>the shield braid into a lead, and adding a short
>pigtail to fit the PC hole if necessary. I'll use the
>stronger outer braid to hold the cable to the board,
>then solder the inner conductor.  It's made much
>easier if the pads to be soldered to are tinned, as
>well; this minimizes the need for heat, and cold
>solder joints.

I always have trouble getting the braid in the hole in the first place as
there's always a stray wire that escapes (especially if the hole isn't
quite big enough--PCB designers take note, I've had to re-drill for
RG-174/U more than once). That's why I tin the braid first. I didn't make
that clear in my first reply--I use a heatsink while I'm *tinning* the
braid. After that it goes right in the hole (it'll now fit a surprisingly
small hole) and a quick touch is all that's needed to solder it.
Furthermore, the braid is now solid and holds the cable up off the board,
which takes a lot of the stress off the inner wire, minimizing breakage.

Tinning the board is, of course, always a good idea.

I also broke down and bought a little coax stripper (the one from Radio
Shack that looks like a piece of Meso-American sculpture done in black
plastic), which saves time and hassle when you're soldering lots of coax.
Makes building stuff less of a drag and reduces the stupid mistakes you
make when you're in a hurry to get the damn thing working, plus your work
looks more professional.


>For switches, I get out the X-Acto (hobby) knife, and
>scrape the oxidation from the solder lugs - gently,
>until they're shiny again.  Then, a quick tinning of
>the lugs.  The resultant solder joint will easily hold
>the wire and lug together without a great deal of
>heat, and will produce a nice, shiny fillet.  Works
>great with potentiometer lugs/pins, too!

I've had this problem with tiny toggle switches, too. A few seconds with
the Weller WTCP and the plastic starts to deform! Cleaning/tinning sounds
like an good idea.


>As a side note, I usually tin the IC pads on my
>boards, as well.  Even when just inserting sockets
>(which, as I'm sure you know, are also
>heat-sensitive), it makes a nice, clean joint, and
>helps to avoid solder bridges between pads.

With my luck I'll end up with holes full of solder. The WTCP works wonders.

I had a batch of socket once that wouldn't take solder. The plating came
off when you heated them!

-- 
Terry Bowman, KA4HJH
"The Mac Doctor"

In a message dated 2/22/2001 5:42:16 PM, droscar@... writes:

>I always have trouble getting the braid in the hole in the first place
>as
>there's always a stray wire that escapes (especially if the hole isn't
>quite big enough--PCB designers take note, I've had to re-drill for
>RG-174/U more than once). That's why I tin the braid first.


Of course all the cable in the MOTM kits comes pre-stripped, pre-tinned (and 
pre-twisted when appropriate).

>Tinning the board is, of course, always a good idea.


I wouldn't do this with the MOTM plate through holes, it seems to take a fair 
bit of extra work to clean the solder out of the holes on these PCBs when one 
makes a mistake -- or so I've heard from those other Stooges that make 
mistakes.

>I also broke down and bought a little coax stripper (the one from Radio
>Shack that looks like a piece of Meso-American sculpture done in black
>plastic), which saves time and hassle when you're soldering lots of coax.

Thanks for this advice Terry, I may have to check this one out!

John (not pre-twisted, I had to work hard to become this Way) Barlow

>Those damn switches don't seem to like the heat of a soldering iron.

I too have noticed this problem on other makes of toggle switches, but
not on the ones Paul supplies. But I am now very careful with any toggle
switches, best not spend more than one second on any one contact.

Regards,

Tony Allgood  Penrith, Cumbria, England

www.techrepairs.freeserve.co.uk

Hi All !

May have misunderstood something here, but all MOTM pc-boards are 
roller tinned .  Totally superfluous to tin the tinned board again %^)

And on a freshly home-made board, even before drilling, i spray some 
kontakt chemie solder laquer, keeps the bare copper from oxidising 
and solders beautifully .

When soldering the coax to the boards, i start with the core .  I 
found that when first soldering the braid, many a time the center 
conductor is then put under a bending load .  When soldering takes a 
tad too long (this can always happen :) ), the hot core wire will cut 
through the poyethylene insulation like a hot knife through butter .  
Hence i start with the core without bending it much at all .  Then 
the braid, not tight at all, so there is some air on the component 
side .  And i do not twist this, close to the core .  This again to 
put no cutting strain on the core .  This bit of slack is neatly 
tucked under when fixing the coax with the tie .

Cheers .


Keep 'em oscillating :)


Hugo
=

Interesting how everyone's successful coax install techniques vary. 
My procedure is somewhat different than this. I bend the shield at a 
sharp 90 degree angle to the cable, and also bend the core lead at 
the same 90 degree angle, making sure that the bend takes place right 
AFTER the insulation ends. Now I can place the coax such that both 
wires go in the holes without struggling. Usually, the shield will 
not go quite all the way down flush because there is slightly more 
distance between the wire leads than the holes. I solder the core, 
then take a pair of needlenose pliers and gently pull the shield 
through the hole a little further so that it lays flush, and solder 
the shield. The goal is to make the wire connect as flat as possible 
(but without sideways strain to cause melt-through). That way you can 
cinch the coax down tight with the cable tie. This works great for me.

Moe

--- In motm@y..., "Hugo Haesaert" <hugo.haesaert@s...> wrote:
> When soldering the coax to the boards, i start with the core .  I 
> found that when first soldering the braid, many a time the center 
> conductor is then put under a bending load .  When soldering takes 
a 
> tad too long (this can always happen :) ), the hot core wire will 
cut 
> through the poyethylene insulation like a hot knife through 
butter .  

> Hence i start with the core without bending it much at all .  Then 
> the braid, not tight at all, so there is some air on the component 
> side .  And i do not twist this, close to the core .  This again to 
> put no cutting strain on the core .  This bit of slack is neatly 
> tucked under when fixing the coax with the tie .

This EXACTLY what I do.  It is extremely fast and accurate.  I have never
had any problems (knock on wood).

--Shemp

> Interesting how everyone's successful coax install techniques vary.
> My procedure is somewhat different than this. I bend the shield at a
> sharp 90 degree angle to the cable, and also bend the core lead at
> the same 90 degree angle, making sure that the bend takes place right
> AFTER the insulation ends. Now I can place the coax such that both
> wires go in the holes without struggling. Usually, the shield will
> not go quite all the way down flush because there is slightly more
> distance between the wire leads than the holes. I solder the core,
> then take a pair of needlenose pliers and gently pull the shield
> through the hole a little further so that it lays flush, and solder
> the shield. The goal is to make the wire connect as flat as possible
> (but without sideways strain to cause melt-through). That way you can
> cinch the coax down tight with the cable tie. This works great for me.
> Moe

I've gotten into the habit of tying them down first. I insert the core, then
ease the braid in, then hold it flat with a fingertip while pulling the
wire-tie through and cinching it. Since I've done this, I haven't had the
"hot knife (wire) through butter (insulation)" problem again. I think this
is because the wire is stationary when I bring the iron into contact with it
and the pad.

I'm surprised several people have had trouble melting switches. My problem
is always the plastic jack cases and existing coax! Fitting the iron in
there can be tricky when finishing up attaching the jacks to the panel.

Make sure to keep your iron's tip tinned. Perhaps you're not getting enough
surface area heat on there and when you bring it into contact the heat is
uneven--not giving enough where you need it but too much elsewhere. If you
notice gaps in the shininess of your tip, clean it (wipe on damp sponge) and
(if you don't have a spare available) gently sand it with very fine
sandpaper. This will give it a new lease on life. Mind you, this is
something I did on my own (without consultation with Paul S or any other
soldering guru), but it completely revitalized a tip I had; it's been
perfect for over a year since sanding it, so I don't think it's a problem.

I just keep my iron hot and never, ever leave it touching anything for more
than a second. I have the solder ready at the joint, and I don't touch the
iron to the board and component until my hand knows exactly where it's
going. With precision, one shouldn't have to hold it long at all. The only
ones that take a second go-round sometimes are the posts for the MTA
connector, and I think that's only because there's more surface area to deal
with and I'm stingy with the solder (not too much!)

Take care,

David.

> -----Original Message-----
> From: mate_stubb@... [mailto:mate_stubb@...]
> Sent: Friday, February 23, 2001 10:46 AM
> To: motm@yahoogroups.com
> Subject: [motm] Re: coaxion -> switch destruction
> 
> 
> Interesting how everyone's successful coax install techniques vary. 
> My procedure is somewhat different than this. I bend the shield at a 
> sharp 90 degree angle to the cable, and also bend the core lead at 
> the same 90 degree angle, making sure that the bend takes place right 
> AFTER the insulation ends. Now I can place the coax such that both 
> wires go in the holes without struggling. Usually, the shield will 
> not go quite all the way down flush because there is slightly more 
> distance between the wire leads than the holes. I solder the core, 
> then take a pair of needlenose pliers and gently pull the shield 
> through the hole a little further so that it lays flush, and solder 
> the shield. The goal is to make the wire connect as flat as possible 
> (but without sideways strain to cause melt-through). That way you can 
> cinch the coax down tight with the cable tie. This works great for me.
> 
> Moe
> 
> --- In motm@y..., "Hugo Haesaert" <hugo.haesaert@s...> wrote:
> > When soldering the coax to the boards, i start with the core .  I 
> > found that when first soldering the braid, many a time the center 
> > conductor is then put under a bending load .  When soldering takes 
> a 
> > tad too long (this can always happen :) ), the hot core wire will 
> cut 
> > through the poyethylene insulation like a hot knife through 
> butter .  
> > Hence i start with the core without bending it much at all .  Then 
> > the braid, not tight at all, so there is some air on the component 
> > side .  And i do not twist this, close to the core .  This again to 
> > put no cutting strain on the core .  This bit of slack is neatly 
> > tucked under when fixing the coax with the tie .
> 
> 
> 
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