Soundcraftsmen A5002 passes 20v dc

[saj888]

Hi all.
I have a soundcraftsmen a 5002 that passes -20v dc. on ch2. Problem is on the driver board, Power supply voltages are normal. Almost everything tests good.. How do I use Voltage checks to trouble shoot this problem?. Thanks in advance. Have a blessed day.

 

[rayma]

Could be that the capacitor C5 is shorted.
See the schematic.

 

[saj888]

Thanks. i replaced c5 and Q1 and q2. same problem

 

[rayma]

Then when unpowered, test all of the PN junctions in-circuit.

 

[saj888]

They all test good. I also replaced the 2 3440 and 2 5416

 

[rayma]

Compare the DC voltages between channels.
Mark up the schematic with good and bad voltages.