Yorkville 400B Bass Head Repair Help

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I've got a Yorkville 400B that stopped working recently. It served me great for many, many years until some drunken fool from another band knocked it off a stage (and didn't apologize). Pretty rude if you ask me since he showed up without a bass amp in the first place and assumed he could use mine. Anyway enough rambling.

The head took quite the spill. It's got a permanently attached power cable which was yanked on. The grommet came out and the connection terminal to the circuit board was tugged on. I took it apart and resoldered that and it worked for a gig or two. Now it doesn't again.

It's very quiet, and the sound is very distorted. It's almost like a flanger type sound making single notes sound out of tune.

It took quite the physical jolt so I'm wondering if some transistor legs got snapped or something.

It's a class B amp I'm sure, and luckily came with schematics.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.


I've repaired a few amps (mostly car amps) over the years, but not for awhile and also this amp has got to be fixed so if I can't fix it myself I'll hand it to a shop. I'm sure there are some easy things I could check before hand though. Any ideas?

Thanks,
Pete


edit: my links didn't work. I'll try to attach.

Schematics
 
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