My flexwave 120h amp head pops when I turn it on and stays humming while playing

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its the reverb tank spring, look where it is connected on the other side. this will give you an idea as to where it was connected. solder it back on.

Reverb spring end broke. you can bend a new loop with pliers. There is a post sticking up in side the metal case that hooks around the end(s)

That is probably a momentary switch that is dirty and sticking. These onboard effects on guitar amps are usually nothing more than a computer sound card and I've found bad connections going to and from them as well. I do think that switch is dirty and sticking, though.

Solid state amps are very subject to blowing out the output transistors if speaker leads get shorted. Take it in for repair.

Hi there,I have the same problem with my flexwave 120. I opened the amp to measure several capacitors on the small effect circuit board. If one of this capaciters have internal short circuit, wich will effect the others causing effects to fail. I removed them one by one to find possible short circuit. All capacitors were ok. I think the problem is in the processor wich is to diffucult to replace. I think it's easier to replace the effects circuit board. But where do we find this board??

Josh,

I also need schematics for this amp. How about whoever finds it first shares with the other?
Cool, Thanks,
bob at stumpweb.com

Perhaps you have a bad capacitor on your volume control?

You can get an ESR meter and test your exposed isolation caps for leakage? The have to be removed so unplug the unit if you are gonna do any work inside the cabinet.

Also, try a shorter or higher quality guitar cable. This will cut impedance between the pickups and the amp.

Good luck and be careful!

You have a broken solder joint. You'll have to disassemble the amp enough to get at the soldered side of the circuit board that the controls are mounted to and touch up any suspect solder joints. Just be sure to resolder only the joints that were originally soldered or need to be soldered. Hope this helps.