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Another KLM367 clone issue: MG Delay

Another KLM367 clone issue: MG Delay

2011-07-27 by Malte Rogacki

This has come up in various degrees with several boards so I guess this
could be a more common problem.

Short description: MG Delay doesn't always work reliable

Long description: I'm getting different times for the MG Delay depending on
the time between key presses. If there is a longer time between key release
and new key press (several seconds) the MG Delay time will be significantly
shorter.
It should be noted that this is also present with original KLM367 boards
albeit to a lesser degree. For example, one original board I have has a
"regular" maximum delay of about 9 seconds; this drops to about 7 seconds
under the above scenario.
However with the clone boards the behaviour can be more severe. I'm having
one that behaves about the same as the original board; however another one
has a maximum delay time of about 7 seconds which drops to less than one
second in the above scenario.

I suspect T5 (Q5) to be the culprit here; swapping this with another one
resulted in a maximum time of about 7 seconds and a minimum time of about 3
seconds. However swapping this with the original 2SC945 (of course I took
care of the correct orientation) resulted in near perfect behaviour.

So the question is if the 2N3904 is really a good substitute for the
2SC945? There are of course some tolerances; however that those tolerances
result in such different results strikes me as odd. Or is that batch of
2N3904 really that bad? What have the other clone builders experienced?

RE: [PolySix] Another KLM367 clone issue: MG Delay

2011-07-27 by backshall1 (dsl)

Yes, I sure have seen this. With a 2 second delay set, if I don't press any
keys for a while and then press one, the MG is on immediately. If I play
notes no more than a couple seconds apart, the delay is 2 seconds. Has
anyone noticed that C33 is not connected as it appears in the schematics?
The schematics show it connected to the top of R98 and IC 14 pin 3, but it
looks like on both the new and old boards it is connected to the bottom of
R98 and the collector of Q5. Weird. Wonder if moving this would change the
problem?
 
Don B.

  _____
Show quoted textHide quoted text
From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
Malte Rogacki
Sent: Wednesday, July 27, 2011 2:16 PM
To: PolySix@yahoogroups.com
Subject: [PolySix] Another KLM367 clone issue: MG Delay


  

This has come up in various degrees with several boards so I guess this
could be a more common problem.

Short description: MG Delay doesn't always work reliable

Long description: I'm getting different times for the MG Delay depending on
the time between key presses. If there is a longer time between key release
and new key press (several seconds) the MG Delay time will be significantly
shorter.
It should be noted that this is also present with original KLM367 boards
albeit to a lesser degree. For example, one original board I have has a
"regular" maximum delay of about 9 seconds; this drops to about 7 seconds
under the above scenario.
However with the clone boards the behaviour can be more severe. I'm having
one that behaves about the same as the original board; however another one
has a maximum delay time of about 7 seconds which drops to less than one
second in the above scenario.

I suspect T5 (Q5) to be the culprit here; swapping this with another one
resulted in a maximum time of about 7 seconds and a minimum time of about 3
seconds. However swapping this with the original 2SC945 (of course I took
care of the correct orientation) resulted in near perfect behaviour.

So the question is if the 2N3904 is really a good substitute for the
2SC945? There are of course some tolerances; however that those tolerances
result in such different results strikes me as odd. Or is that batch of
2N3904 really that bad? What have the other clone builders experienced?





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

RE: [PolySix] Another KLM367 clone issue: MG Delay

2011-07-28 by backshall1 (dsl)

Okay, that didn't work. I unsoldered the positive side of C33 and connected
it to the other end of R98 and that made the problem worse. So, I put the
capacitor back, and tried a cross-legged 2SC945 like Malte said. Problem
solved. There sure seems to be a mismatch with the 2n3904 in this circuit.
 
Don B.

  _____
Show quoted textHide quoted text
From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
backshall1 (dsl)
Sent: Wednesday, July 27, 2011 6:22 PM
To: PolySix@yahoogroups.com
Subject: RE: [PolySix] Another KLM367 clone issue: MG Delay


  

Yes, I sure have seen this. With a 2 second delay set, if I don't press any
keys for a while and then press one, the MG is on immediately. If I play
notes no more than a couple seconds apart, the delay is 2 seconds. Has
anyone noticed that C33 is not connected as it appears in the schematics?
The schematics show it connected to the top of R98 and IC 14 pin 3, but it
looks like on both the new and old boards it is connected to the bottom of
R98 and the collector of Q5. Weird. Wonder if moving this would change the
problem?

Don B.

_____ 

From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
[mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ] On
Behalf Of
Malte Rogacki
Sent: Wednesday, July 27, 2011 2:16 PM
To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> 
Subject: [PolySix] Another KLM367 clone issue: MG Delay

This has come up in various degrees with several boards so I guess this
could be a more common problem.

Short description: MG Delay doesn't always work reliable

Long description: I'm getting different times for the MG Delay depending on
the time between key presses. If there is a longer time between key release
and new key press (several seconds) the MG Delay time will be significantly
shorter.
It should be noted that this is also present with original KLM367 boards
albeit to a lesser degree. For example, one original board I have has a
"regular" maximum delay of about 9 seconds; this drops to about 7 seconds
under the above scenario.
However with the clone boards the behaviour can be more severe. I'm having
one that behaves about the same as the original board; however another one
has a maximum delay time of about 7 seconds which drops to less than one
second in the above scenario.

I suspect T5 (Q5) to be the culprit here; swapping this with another one
resulted in a maximum time of about 7 seconds and a minimum time of about 3
seconds. However swapping this with the original 2SC945 (of course I took
care of the correct orientation) resulted in near perfect behaviour.

So the question is if the 2N3904 is really a good substitute for the
2SC945? There are of course some tolerances; however that those tolerances
result in such different results strikes me as odd. Or is that batch of
2N3904 really that bad? What have the other clone builders experienced?

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






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

Re: [PolySix] Another KLM367 clone issue: MG Delay

2011-07-28 by Andrew Jury

Strange! The only two real big differences between the 2SC945 and 2N3904 are
the leg positions and the Hfe. The 2N has a far superior gain in this
respect. Perhaps the difference in the current characteristics is effecting
the timing constants in the circuit? I think I¹ll go and try a BC547 and see
what happens...

Cheers,
Andy

On 28/07/2011 03:17, "backshall1 (dsl)" <backshall1@bellsouth.net> wrote:

>  
>  
>  
>    
> 
> Okay, that didn't work. I unsoldered the positive side of C33 and connected
> it to the other end of R98 and that made the problem worse. So, I put the
> capacitor back, and tried a cross-legged 2SC945 like Malte said. Problem
> solved. There sure seems to be a mismatch with the 2n3904 in this circuit.
>  
> Don B.
> 
> _____  
> 
> From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ] On Behalf
> Of
> backshall1 (dsl)
> Sent: Wednesday, July 27, 2011 6:22 PM
> To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> Subject: RE: [PolySix] Another KLM367 clone issue: MG Delay
> 
> Yes, I sure have seen this. With a 2 second delay set, if I don't press any
> keys for a while and then press one, the MG is on immediately. If I play
> notes no more than a couple seconds apart, the delay is 2 seconds. Has
> anyone noticed that C33 is not connected as it appears in the schematics?
> The schematics show it connected to the top of R98 and IC 14 pin 3, but it
> looks like on both the new and old boards it is connected to the bottom of
> R98 and the collector of Q5. Weird. Wonder if moving this would change the
> problem?
> 
> Don B.
> 
> _____ 
> 
> From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> <mailto:PolySix%40yahoogroups.com>
> [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> <mailto:PolySix%40yahoogroups.com> ] On
> Behalf Of
> Malte Rogacki
> Sent: Wednesday, July 27, 2011 2:16 PM
> To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> <mailto:PolySix%40yahoogroups.com>
> Subject: [PolySix] Another KLM367 clone issue: MG Delay
> 
> This has come up in various degrees with several boards so I guess this
> could be a more common problem.
> 
> Short description: MG Delay doesn't always work reliable
> 
> Long description: I'm getting different times for the MG Delay depending on
> the time between key presses. If there is a longer time between key release
> and new key press (several seconds) the MG Delay time will be significantly
> shorter.
> It should be noted that this is also present with original KLM367 boards
> albeit to a lesser degree. For example, one original board I have has a
> "regular" maximum delay of about 9 seconds; this drops to about 7 seconds
> under the above scenario.
> However with the clone boards the behaviour can be more severe. I'm having
> one that behaves about the same as the original board; however another one
> has a maximum delay time of about 7 seconds which drops to less than one
> second in the above scenario.
> 
> I suspect T5 (Q5) to be the culprit here; swapping this with another one
> resulted in a maximum time of about 7 seconds and a minimum time of about 3
> seconds. However swapping this with the original 2SC945 (of course I took
> care of the correct orientation) resulted in near perfect behaviour.
> 
> So the question is if the 2N3904 is really a good substitute for the
> 2SC945? There are of course some tolerances; however that those tolerances
> result in such different results strikes me as odd. Or is that batch of
> 2N3904 really that bad? What have the other clone builders experienced?
> 
> [Non-text portions of this message have been removed]
> 
> [Non-text portions of this message have been removed]
> 
>  
>    
> 
> 



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

Re: [PolySix] Another KLM367 clone issue: MG Delay

2011-07-28 by Malte Rogacki

As far as I can remember (I did measurements the last time but not this
time around) the voltage on pin 3 of IC14 doesn't drop sufficiently; and
this could be because it was higher to begin with. Could be that C33
doesn't get completely discharged.

Re: [PolySix] Another KLM367 clone issue: MG Delay

2011-07-29 by Malte Rogacki

Here are a few more observations/measurements. Feel free to correct:

Pin 2 on IC14 gets the control voltage for the MG delay; the range is
between about -4.6V (Delay 0) and +4.6V (Delay 10).
Pin 3 on IC14 gets a voltage that is "ramped up" from -5V (to about +13V).
IC14 then acts as a comparator/Schmitt trigger, changing its state from
-15V to +15V.

So basically if the voltage on Pin 2 is very low (Delay 0) the ramp on Pin
3 will cause IC14 to switch immediately or nearly immediately. However if
the voltage on Pin 2 is higher the switch will occur after some time has
passed and the voltage on Pin 3 has gotten higher.

The ramp on Pin 3 is reset with every NEW gate signal coming from KLM366.
As long as keys are held no new gate signal is happening; for a new gate
signal all keys need to be released first.

What is happening with the clone is that this reset doesn't always start
the ramp at -5V; sometimes the reset doesn't reach the full depth and the
ramping starts around +2V or so. Which of course means that IC14 switches
it's state earlier than intended (because the ramp takes less time to reach
the "switching point" since it didn't start low enough).
This leads me to believe that C33 isn't fully discharged.

Re: Another KLM367 clone issue: MG Delay

2011-09-18 by Mike

I know you don't have the board, but do you have an idea of how much it will cost?  Also, how do you want to get paid?

-Mike

--- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
Show quoted textHide quoted text
>
> Strange! The only two real big differences between the 2SC945 and 2N3904 are
> the leg positions and the Hfe. The 2N has a far superior gain in this
> respect. Perhaps the difference in the current characteristics is effecting
> the timing constants in the circuit? I think I¹ll go and try a BC547 and see
> what happens...
> 
> Cheers,
> Andy
> 
> On 28/07/2011 03:17, "backshall1 (dsl)" <backshall1@...> wrote:
> 
> >  
> >  
> >  
> >    
> > 
> > Okay, that didn't work. I unsoldered the positive side of C33 and connected
> > it to the other end of R98 and that made the problem worse. So, I put the
> > capacitor back, and tried a cross-legged 2SC945 like Malte said. Problem
> > solved. There sure seems to be a mismatch with the 2n3904 in this circuit.
> >  
> > Don B.
> > 
> > _____  
> > 
> > From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ] On Behalf
> > Of
> > backshall1 (dsl)
> > Sent: Wednesday, July 27, 2011 6:22 PM
> > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > Subject: RE: [PolySix] Another KLM367 clone issue: MG Delay
> > 
> > Yes, I sure have seen this. With a 2 second delay set, if I don't press any
> > keys for a while and then press one, the MG is on immediately. If I play
> > notes no more than a couple seconds apart, the delay is 2 seconds. Has
> > anyone noticed that C33 is not connected as it appears in the schematics?
> > The schematics show it connected to the top of R98 and IC 14 pin 3, but it
> > looks like on both the new and old boards it is connected to the bottom of
> > R98 and the collector of Q5. Weird. Wonder if moving this would change the
> > problem?
> > 
> > Don B.
> > 
> > _____ 
> > 
> > From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > <mailto:PolySix%40yahoogroups.com>
> > [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > <mailto:PolySix%40yahoogroups.com> ] On
> > Behalf Of
> > Malte Rogacki
> > Sent: Wednesday, July 27, 2011 2:16 PM
> > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > <mailto:PolySix%40yahoogroups.com>
> > Subject: [PolySix] Another KLM367 clone issue: MG Delay
> > 
> > This has come up in various degrees with several boards so I guess this
> > could be a more common problem.
> > 
> > Short description: MG Delay doesn't always work reliable
> > 
> > Long description: I'm getting different times for the MG Delay depending on
> > the time between key presses. If there is a longer time between key release
> > and new key press (several seconds) the MG Delay time will be significantly
> > shorter.
> > It should be noted that this is also present with original KLM367 boards
> > albeit to a lesser degree. For example, one original board I have has a
> > "regular" maximum delay of about 9 seconds; this drops to about 7 seconds
> > under the above scenario.
> > However with the clone boards the behaviour can be more severe. I'm having
> > one that behaves about the same as the original board; however another one
> > has a maximum delay time of about 7 seconds which drops to less than one
> > second in the above scenario.
> > 
> > I suspect T5 (Q5) to be the culprit here; swapping this with another one
> > resulted in a maximum time of about 7 seconds and a minimum time of about 3
> > seconds. However swapping this with the original 2SC945 (of course I took
> > care of the correct orientation) resulted in near perfect behaviour.
> > 
> > So the question is if the 2N3904 is really a good substitute for the
> > 2SC945? There are of course some tolerances; however that those tolerances
> > result in such different results strikes me as odd. Or is that batch of
> > 2N3904 really that bad? What have the other clone builders experienced?
> > 
> > [Non-text portions of this message have been removed]
> > 
> > [Non-text portions of this message have been removed]
> > 
> >  
> >    
> > 
> > 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

Re: Another KLM367 clone issue: MG Delay

2011-09-18 by Mike

Also,

How long do you think it will take to fix?

-Mike

--- In PolySix@yahoogroups.com, "Mike" <mborish_2000@...> wrote:
Show quoted textHide quoted text
>
> I know you don't have the board, but do you have an idea of how much it will cost?  Also, how do you want to get paid?
> 
> -Mike
> 
> --- In PolySix@yahoogroups.com, Andrew Jury <andy@> wrote:
> >
> > Strange! The only two real big differences between the 2SC945 and 2N3904 are
> > the leg positions and the Hfe. The 2N has a far superior gain in this
> > respect. Perhaps the difference in the current characteristics is effecting
> > the timing constants in the circuit? I think I¹ll go and try a BC547 and see
> > what happens...
> > 
> > Cheers,
> > Andy
> > 
> > On 28/07/2011 03:17, "backshall1 (dsl)" <backshall1@> wrote:
> > 
> > >  
> > >  
> > >  
> > >    
> > > 
> > > Okay, that didn't work. I unsoldered the positive side of C33 and connected
> > > it to the other end of R98 and that made the problem worse. So, I put the
> > > capacitor back, and tried a cross-legged 2SC945 like Malte said. Problem
> > > solved. There sure seems to be a mismatch with the 2n3904 in this circuit.
> > >  
> > > Don B.
> > > 
> > > _____  
> > > 
> > > From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > > [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> ] On Behalf
> > > Of
> > > backshall1 (dsl)
> > > Sent: Wednesday, July 27, 2011 6:22 PM
> > > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > > Subject: RE: [PolySix] Another KLM367 clone issue: MG Delay
> > > 
> > > Yes, I sure have seen this. With a 2 second delay set, if I don't press any
> > > keys for a while and then press one, the MG is on immediately. If I play
> > > notes no more than a couple seconds apart, the delay is 2 seconds. Has
> > > anyone noticed that C33 is not connected as it appears in the schematics?
> > > The schematics show it connected to the top of R98 and IC 14 pin 3, but it
> > > looks like on both the new and old boards it is connected to the bottom of
> > > R98 and the collector of Q5. Weird. Wonder if moving this would change the
> > > problem?
> > > 
> > > Don B.
> > > 
> > > _____ 
> > > 
> > > From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > > <mailto:PolySix%40yahoogroups.com>
> > > [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > > <mailto:PolySix%40yahoogroups.com> ] On
> > > Behalf Of
> > > Malte Rogacki
> > > Sent: Wednesday, July 27, 2011 2:16 PM
> > > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
> > > <mailto:PolySix%40yahoogroups.com>
> > > Subject: [PolySix] Another KLM367 clone issue: MG Delay
> > > 
> > > This has come up in various degrees with several boards so I guess this
> > > could be a more common problem.
> > > 
> > > Short description: MG Delay doesn't always work reliable
> > > 
> > > Long description: I'm getting different times for the MG Delay depending on
> > > the time between key presses. If there is a longer time between key release
> > > and new key press (several seconds) the MG Delay time will be significantly
> > > shorter.
> > > It should be noted that this is also present with original KLM367 boards
> > > albeit to a lesser degree. For example, one original board I have has a
> > > "regular" maximum delay of about 9 seconds; this drops to about 7 seconds
> > > under the above scenario.
> > > However with the clone boards the behaviour can be more severe. I'm having
> > > one that behaves about the same as the original board; however another one
> > > has a maximum delay time of about 7 seconds which drops to less than one
> > > second in the above scenario.
> > > 
> > > I suspect T5 (Q5) to be the culprit here; swapping this with another one
> > > resulted in a maximum time of about 7 seconds and a minimum time of about 3
> > > seconds. However swapping this with the original 2SC945 (of course I took
> > > care of the correct orientation) resulted in near perfect behaviour.
> > > 
> > > So the question is if the 2N3904 is really a good substitute for the
> > > 2SC945? There are of course some tolerances; however that those tolerances
> > > result in such different results strikes me as odd. Or is that batch of
> > > 2N3904 really that bad? What have the other clone builders experienced?
> > > 
> > > [Non-text portions of this message have been removed]
> > > 
> > > [Non-text portions of this message have been removed]
> > > 
> > >  
> > >    
> > > 
> > > 
> > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
>

RE: [PolySix] Re: Another KLM367 clone issue: MG Delay

2011-09-18 by backshall1

No charge, other than parts and return postage, as long as you don’t mind me
posting the results to the group here. It’s an education thing, to enlighten
the group on things that can go wrong with a clone board build. We’re here
to help, right? It might take a couple of weeks to get it diagnosed and
going again, since I don’t have a lot of spare time. I can’t imagine it
would need much in the way of parts.

Don B.

 

  _____
Show quoted textHide quoted text
From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
Mike
Sent: Saturday, September 17, 2011 11:10 PM
To: PolySix@yahoogroups.com
Subject: [PolySix] Re: Another KLM367 clone issue: MG Delay

 

  

Also,

How long do you think it will take to fix?

-Mike

--- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , "Mike"
<mborish_2000@...> wrote:
>
> I know you don't have the board, but do you have an idea of how much it
will cost? Also, how do you want to get paid?
> 
> -Mike
> 
> --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew
Jury <andy@> wrote:
> >
> > Strange! The only two real big differences between the 2SC945 and 2N3904
are
> > the leg positions and the Hfe. The 2N has a far superior gain in this
> > respect. Perhaps the difference in the current characteristics is
effecting
> > the timing constants in the circuit? I think I¹ll go and try a BC547 and
see
> > what happens...
> > 
> > Cheers,
> > Andy
> > 
> > On 28/07/2011 03:17, "backshall1 (dsl)" <backshall1@> wrote:
> > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > Okay, that didn't work. I unsoldered the positive side of C33 and
connected
> > > it to the other end of R98 and that made the problem worse. So, I put
the
> > > capacitor back, and tried a cross-legged 2SC945 like Malte said.
Problem
> > > solved. There sure seems to be a mismatch with the 2n3904 in this
circuit.
> > > 
> > > Don B.
> > > 
> > > _____ 
> > > 
> > > From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
<mailto:PolySix%40yahoogroups.com>
> > > [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
<mailto:PolySix%40yahoogroups.com> ] On Behalf
> > > Of
> > > backshall1 (dsl)
> > > Sent: Wednesday, July 27, 2011 6:22 PM
> > > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
<mailto:PolySix%40yahoogroups.com>
> > > Subject: RE: [PolySix] Another KLM367 clone issue: MG Delay
> > > 
> > > Yes, I sure have seen this. With a 2 second delay set, if I don't
press any
> > > keys for a while and then press one, the MG is on immediately. If I
play
> > > notes no more than a couple seconds apart, the delay is 2 seconds. Has
> > > anyone noticed that C33 is not connected as it appears in the
schematics?
> > > The schematics show it connected to the top of R98 and IC 14 pin 3,
but it
> > > looks like on both the new and old boards it is connected to the
bottom of
> > > R98 and the collector of Q5. Weird. Wonder if moving this would change
the
> > > problem?
> > > 
> > > Don B.
> > > 
> > > _____ 
> > > 
> > > From: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
<mailto:PolySix%40yahoogroups.com>
> > > <mailto:PolySix%40yahoogroups.com>
> > > [mailto:PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
<mailto:PolySix%40yahoogroups.com>
> > > <mailto:PolySix%40yahoogroups.com> ] On
> > > Behalf Of
> > > Malte Rogacki
> > > Sent: Wednesday, July 27, 2011 2:16 PM
> > > To: PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com>
<mailto:PolySix%40yahoogroups.com>
> > > <mailto:PolySix%40yahoogroups.com>
> > > Subject: [PolySix] Another KLM367 clone issue: MG Delay
> > > 
> > > This has come up in various degrees with several boards so I guess
this
> > > could be a more common problem.
> > > 
> > > Short description: MG Delay doesn't always work reliable
> > > 
> > > Long description: I'm getting different times for the MG Delay
depending on
> > > the time between key presses. If there is a longer time between key
release
> > > and new key press (several seconds) the MG Delay time will be
significantly
> > > shorter.
> > > It should be noted that this is also present with original KLM367
boards
> > > albeit to a lesser degree. For example, one original board I have has
a
> > > "regular" maximum delay of about 9 seconds; this drops to about 7
seconds
> > > under the above scenario.
> > > However with the clone boards the behaviour can be more severe. I'm
having
> > > one that behaves about the same as the original board; however another
one
> > > has a maximum delay time of about 7 seconds which drops to less than
one
> > > second in the above scenario.
> > > 
> > > I suspect T5 (Q5) to be the culprit here; swapping this with another
one
> > > resulted in a maximum time of about 7 seconds and a minimum time of
about 3
> > > seconds. However swapping this with the original 2SC945 (of course I
took
> > > care of the correct orientation) resulted in near perfect behaviour.
> > > 
> > > So the question is if the 2N3904 is really a good substitute for the
> > > 2SC945? There are of course some tolerances; however that those
tolerances
> > > result in such different results strikes me as odd. Or is that batch
of
> > > 2N3904 really that bad? What have the other clone builders
experienced?
> > > 
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> > > 
> > > [Non-text portions of this message have been removed]
> > > 
> > > 
> > > 
> > > 
> > > 
> > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
>





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