It's Alive!

[NowYou'rePlayingWithPower]

No, not Frankenstein, but my JTM30 that "died" a few months ago under the care of my daughter. Turned out one of the prongs for the power cable inlet was broken out, so explains why it wouldn't power on. Everything seems good with it now that's been replaced, but now there is an imbalance in volume between the green and red channel. The red channel is a lot quieter. Already swapped tubes around and cleaned the pots as well as have a cable in the loop. Any other tips or things to look out for? I know this amp isn't sought after, but I've had it for about 30 years. So, would love to keep it going. Thanks y'all!

 

[glpg80]

Assuming all that was done was done correctly, I think there’s a failing electrolytic cap in the channel switching supply or involving the channel switching in general.

Amp needs a cap overhaul and a good tech overview.

 

[NowYou'rePlayingWithPower]

Assuming all that was done was done correctly, I think there’s a failing electrolytic cap in the channel switching supply or involving the channel switching in general.

Amp needs a cap overhaul and a good tech overview.

Thanks, I'll pull it apart and take a look at it to see if I can trace it down.
I replaced all the caps around 2010, so probably in need anyways.
Was messing around with it a bit and noticed that it doesn't have the issue when using the footswitch, just with the push switch.
Does that even make sense? Could it just be that switch making poor contact? Looking at the schematic seems like it wouldn't make any difference.
I have some other switches that I can try.

 

[glpg80]

Thanks, I'll pull it apart and take a look at it to see if I can trace it down.
I replaced all the caps around 2010, so probably in need anyways.
Was messing around with it a bit and noticed that it doesn't have the issue when using the footswitch, just with the push switch.
Does that even make sense? Could it just be that switch making poor contact? Looking at the schematic seems like it wouldn't make any difference.
I have some other switches that I can try.

Footswitch interrupts the switch with its own to ground. Could be a bad switch or a bad ground. Check the soldering on the switch and make sure it’s fully soldered.

 

[LuluLala]

Back in the day I had a Fender Bassman Blackface head. One day I turned it on and it wasn't working. I looked in the back and my nephew had jammed a toy car into it and had damaged it. I took it to get it fixed, it worked but it never sounded the same to me. My friends who had played it before said that it sounded fine but to me something was off. I hope yours turns out fine.