Peavey bandit 65 feedback problems

[Peaveyman]

Hello again
I came to think of an old peavey amp I haven't used for a while, when disassembling it it will play well for some time but when I decide to put it together I quickly get escalating feedback up to full volume so I have to turn it off immediately.
I tried decoupling the reverb unit and put my fingers on most of the components to see if I could spot a mechanical problem, but nothing found yet.
It doesn't matter if the amp is unplugged or plugged and I've tried another woofer as well.

Would be very greatful if anyone have a good solution for this annoying problem.

[pecorporation]

How does the solder look on the jacks and pots? Is there any cracked solder points or cold solder connections? I'd look first at the components that stress the pc board as it is mounted.

[chipprogr]

Check the 4 screws on the top of the amp. THe ones that hold the chassis in place. Are 3 of them the same length and 1 shorter? IF memory serves me correctly - You may have put the short screw in the wrong location and accidentally driven a long screw right into the circuit board (back right side) right where the channel switch circuitry is. This is the location for the short screw.