Help! Gremlins are attacking my B-52 LG100a amplifier

[bouttree]

I have a B-52 Stealth Series LG100a guitar Amplifier . The amp. had a humming feed back problem. I opened up the head case and searched for any obvious trouble, loose wires, bad grounds, burn and over heat conditions potentiometers, switches and plugs. When I plugged in the guitar and turned on the amp, there was a low output of sound. I checked all connections and cables all was good. I tapped on everything and nothing seemed to be intermittent (everything worked before I opened up the head case.
I checked the resistance on all the switches,looked for any damage I may have done and everything looks okay.
I can find no schematics or forum help for this B-52 head model. This is a LG 100a which is solid state not a tube amp. I can find plenty of information for the B-52 Tube amp.
Can any one help me with this malfunction? I don't want to spend money on a service technician. I could fix this problem if I had the proper schematic and a suggestion on troubleshooting. I have no idea where to begin to find whats broke. No smells or obvious trouble that I have seen.
I am a retired F-16 electrician, I have a decent repair shop in my basement. I would really appreciate any help or advice.
e-mail [ electenv@yahoo.com ]
telephone [812-249-3823 ]
Thank You,
Dennis.
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[Roly]

Hi bouttree/Dennis, and welcome!


B-52 LG 100a which is solid state


Prelim;

humming feed back

Please post short sound clip.

I can find no schematics or forum help for this B-52 head model.

Okay, so we'll need a few crisp pix of the front panel so we can get some idea of what it does (e.g. link from Google images) the insides, top and bottom, will help a lot.
(Post here or via your imageserver)

Does this amp have an Fx Loop, Fx Send/Return, Pre Out/Main In sockets?

If so, plug a known good lead into each and report if the symptoms change or not.

Disconnect the loudspeaker and measure the voltage across the output.  If it is more than about 500mV (0.5V) then do not re-connect the speaker (it may get damaged).