Solid State Guitar Amp Forum | DIY Guitar Amplifiers

I have a Randall G3 75w G3 combo amp. I have a problem with the volume. When I play the volume will suddenly get very loud then a bit later go back to normal volume. I have tried different guitar cords.  I was thinking maybe it was related to where I was plugging in being on a power strip with my pedals. I ran it stand alone being the only device plugged in and still have the issue. I have noticed I can cause the change by putting some weight on the top of the cab. I suppose I should just open up the cab and take a look. What do you guys think it could be?

You can pull the chassis out, play some recorded music through it (so both your hands are free) and carefully press here and there, move wires, slightly press on parts, pots, jacks, *slightly* bend the PCB, with an insulated stick such as a chinese chopstick, a plastic BIC pen, etc. , until you find where the problem appears.
Post results for further suggestions.

I found when the amp was assembled a bolt that holds the amp in was over tightened breaking the clip that holds the nut. When I opened it up pieces came out. I am not sure how me putting weight on the top would Trigger it. I put it back together an d played through it and couldn't reproduce the issue.  Hopefully this was all that was wrong.