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Cgs synth

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Re: CGS82 Negative Slew

2013-10-06 by Stephen Richards

Hi Ken

When the PCB is powered up , if i put my finger on the BC547 in the the 6V section. It is cool to the touch for a few seconds then becomes very hot very quickly.

I have changed out all of the electrolytics and there is no change , i have looked over and over and can't find a short.

Now that the electros in the power filtering are changed , should i put another BC547 in ?

I'm racking my brain but can't find a solution.

From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Saturday, October 5, 2013 12:13 PM
Subject: RE: Re: [cgs_synth] RE: CGS82 Negative Slew

The links are all part of the 0V power rail. with any of them missing, nothing was working properly.


---In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

Thanks Ken

I've been looking for a short , will keep looking.

Any clue on why it works without that link installed ? Could that be the key to tracking down this problem ?

From: "sasami@..." <sasami@...>
To: cgs_synth@yahoogroups.com
Sent: Saturday, October 5, 2013 9:21 AM
Subject: [cgs_synth] RE: CGS82 Negative Slew

First, find where the short circuit is! The transistor should not get hot.

Ken


---In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

Hi Ken and All

I finished building the CGS82 Negative Slew. Had i 'working' , as far as i can understand it so far , but the bottom section LED was not working.

While i was trying to troubleshoot that problem , i noticed i had omitted the link that's between the RATE pads on the PCB and the 22K trimmer.

When i put that link in , every thing seems to have stopped working and the BC547 in the 6V section directly above the 6.8K resistor is getting very hot under power.

Should i replace the BC547 , not too sure how to proceed.




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