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Negative rail problem - kesgreen
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kesgreen  
#1 Posted : Thursday, February 7, 2013 1:22:14 AM(UTC)
kesgreen

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I have a Placid BP (v. 2.12) with a problem. It's been fine for years, but while upgrading to dual-mono, I noticed some wires had slipped under the PCB which may have shorted something. The positive output is fine, but the negative won't go above -13.6V. While trying to measure voltage across R1, LED D6 flashed red and then died. All other LEDs light up fine.
Voltages across negative side components are listed below:

C1 23.49V
C3 10.43V
C5 0V
C7 -19V
C9 -23.42V

R1 0V
R11 9.02V
R9 0.005V

Any ideas?
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kesgreen  
#2 Posted : Thursday, February 7, 2013 9:53:36 PM(UTC)
kesgreen

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I suppose it's time to start randomly replacing components. Perhaps the rectifier and transistors would be the best place to start since I can get all of those from Mouser.

I'll post this on the DIY forum in case anyone there is able to pin down the problem.

Edited by user Thursday, February 7, 2013 9:54:46 PM(UTC)  | Reason: Not specified
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Russ White  
#3 Posted : Thursday, February 7, 2013 10:25:37 PM(UTC)
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Do not cross post. That's not cool. :)

I am looking at the schematic now. My guess is you shorted R1 and simply killed D6
try replacing that first. LEDs are cheap. Get several.
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thanks 1 user thanked Russ White for this useful post.
kesgreen on 2/7/2013(UTC)
kesgreen  
#4 Posted : Thursday, February 7, 2013 10:42:50 PM(UTC)
kesgreen

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Oops, sorry Russ I already posted it and can't delete it.

I'll try replacing the LED. I should have some.
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kesgreen  
#5 Posted : Thursday, February 7, 2013 11:38:49 PM(UTC)
kesgreen

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Worked like a charm. Thanks again!
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Russ White  
#6 Posted : Friday, February 8, 2013 12:57:04 AM(UTC)
Russ White

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No worries. :)

Its just better to only need to respond in one place.
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