amp diagnosis help? fluctuating volume peavey windsor

[primerib]

cheap chinese made peavey. when playing the volume fluctuates a little bit, enough to be noticeable. have new preamp tubes, tried another set of known good power amp tubes. still does it. what should I look at first? Caps? Don't think the SGResistors should drift like that.

 

[311boogieman]

I know you tried new power tubes but.......try some new power tubes.



or a rebias

 

[glip22]

That could be anything. Does your jewel light dim when it happens? More common issues could be a cold solder joint, failing plate resistor, or maybe a failing electrolytic cap. Do the ec's have any leaks or bulges? If you don't know how to troubleshoot, a tech is your best choice. I would start with my chopstick. I would also clean and make sure all pretube sockets were tensioned. Clean your pots also.