Ampeg Gv-22 trem and verb not working

[the#9]

Hi, Thanks for any help in the past on getting this amp going.
I'm trying to get this fine amp working 100%. Both channels work and sound good.
However on the first channel the trem/vib and reverb do not work. Any place to start to check for problems would be helpful.


This is an amp I got recently and I believe sat for some time. I have sprayed all the tube sockets, jacks , pots and switches and changed out the ax7's and the 6gc7 tubes to see if any changes in the fx on channel 1 but nothing. Please help.
Thanks

[Hangman]

While the verb and trem not working is typically not the same issue, the construction of the gv22 does make me wonder. Both the reverb driver and trem/vib circuit use power supply point C. Ampeg typically used rather thin solid core wire on these amps and the verb and trem share a pcb separate from the main pcb, and channels.
So that could be a thought.


When the verb volume is up and you jostle the tank, can you hear the springs rattling though the speaker?

Hi, Thanks for any help in the past on getting this amp going.
I'm trying to get this fine amp working 100%. Both channels work and sound good.
However on the first channel the trem/vib and reverb do not work. Any place to start to check for problems would be helpful.


This is an amp I got recently and I believe sat for some time. I have sprayed all the tube sockets, jacks , pots and switches and changed out the ax7's and the 6gc7 tubes to see if any changes in the fx on channel 1 but nothing. Please help.
Thanks

[the#9]

Thanks for the reply. Your help before worked - changing the tube was the issue with Ch 1. The verb does make a sound when the amp is moved but nothing from the rotary control or the switch above. The trem/vib is completely dead but I can hear a click when I switch the rocker switch above the trem.
Thanks again.

[jjmt]

My money's on the foot switch. Apart from the shared B+ connection through point C (mentioned by Hangman), it is the only *single* thing that explains both not working that I can see. Of course, there could be a more complex issue.

[Hangman]

My money's on the foot switch. Apart from the shared B+ connection through point C (mentioned by Hangman), it is the only *single* thing that explains both not working that I can see. Of course, there could be a more complex issue.

I was initially thinking switch too, but the trem switch would have to fail open while the verb switch would have to fail short, which didn’t seem plausible for me. Plus,the verb can be heard if we jostle the amp, and the verb foot switch is post tank.

I do not recommend going and replacing everything as slider313 suggested. While the shotgun approach can work, it requires a lot of work to maybe solve a problem. Proper diagnosis will save you time. Then once The amp is working, you can consider replacing parts preemptively, some amount of maintainence is obviously recommended. But it shouldn’t be a solution to a problem you haven’t identified.
Just my opinion of course

[Hangman]

as I said, some amount of maintenance is obviously recommended, but randomly replacing things is a really poor way to fix an amp. proper diagnosis will save you time and money every time.

if the electrolytic do need to be replaced they're not going to blow up in the time it takes us to diagnose the actual problem, but if #9 replaces all of the electrolytic caps, and makes a minor error when doing so, and the other problems still persist, then things get really funky. not only do we still have to diagnose the original problems, we have to figure out why the other problem exists and if its related to the first problem or not.

don't mix up maintenance and repair. do repairs first, then maintenance that way you don't end up blowing up things you just replaced.

[jjmt]

I was initially thinking switch too, but the trem switch would have to fail open while the verb switch would have to fail short, which didn’t seem plausible for me.

Yeah, I had that very thought. But in principal they could have gotten stuck that way if left to sit for long enough. Still, I know agree that it's unlikely.

Plus,the verb can be heard if we jostle the amp, and the verb foot switch is post tank.

Actually, in this schematic the foot switch is pre-tank.

I guess the question I have: does this amp have switches on the face plate for trem and verb? If so, which takes precedence, the switch or the foot switch?

[Hangman]

good Catch! I stand corrected. Although the two switches would still have to fail in opposite ways. So I’m hesitant to go with footswitch, but I’ll entertain the posibility. These amps didn’t have on/off switches on the pan l for the verb or trem.