CS 800 Had Fading Channel B but Now has no power

[7rrivera7]

Model: CS 800X
Serial: 09593008
MFG LOC-10 00319510/JHI30

Yesterday I powered up my CS 800 after being in storage for 10 years. I connected my JBLs using 1/4" phono plug output jacks and a tablet with a 3.5mm headphone jack to dual RCA's and converted to 2 phono plugs - one into each channel's high Z inputs. Everything looked and sounded fine and I had music on both channels.

After about 10 mins, the volume on channel B went low. I tried adjusting the gain but it was not outputting like channel A. I turned the amp off and on and it started working again but soon did the same thing so I left it until the next day.

Today I powered it on and only channel A gets power. I powered it off and on again and the sequence is a fast flash from DDT on both channels then channel A powers up but channel B does not. I am a tinkerer and would like a step by step to troubleshoot this issue. Any and all assistance is greatly appreciated.

[7rrivera7]

Update: Today I powered on the amp and both channels came up and sounded fine. I left it playing and suddenly channel B's volume lowered, then raised, then lowered and continued. So todayboth channels are running but channel B's volume changes one it's own.

[DrGonz78]

Trace an input signal through the amp while waiting for the chB to drop out. Then work your way through tracing the signal from the output going backwards to see if the signal returns. You have a working channel that you can compare voltages and signal flow against too. You either need a scope or build a small signal tracer.

[Enzo]

Look on the schematic at the input jack stuff. See the three switches? DDT in/out, PL2 in/out, and Stereo/bridge.

Clean them.

[7rrivera7]

Ok I sent an email to Peavey CS and requested the original schematic diagram. As far as cleaning the switches - electronics contact cleaner is good?

[TomCarlos]

See if this file has what you need...

peavey_cs-800x_1994.zip