Dual rectifier FX problem with SOLO and OUTPUT

Hi my friends! My dual has a problem with fx loop. When fx loop is active SOLO and OUTPUT doesn't work properly, sounds very low. in bypass all channel master works and the volume is perfect. I thought was V4 but isn't.

Still with the problem

What happens when you jump the loop with a cable?

VisaL said:

What happens when you jump the loop with a cable?

Click to expand...

I did It but didn't work.

What is the SEND level at in the rear? That is always in the circuit, so if you have the send set really low, you'll have very low output. I usually keep it right in the middle.

Both in the middle.

V4 is the obvious as it’s for both the send and the return. Intermittent loop jack is another, but since you’ve ruled out those, I think there’s not much else you can do without getting the chassis out and start poking around. You could further narrow it down running the signal from send to another amps return to see does the send provide decent signal. If it does, then problem is between return and V5. Could be wire from pcb to volume coming loose, faulty pot or one of the mute circuit fets.

I'll test the signal out another amplifier. Thank you, I will continue with this issue since I have not found an answer anywhere and I have read the problem of others, but no one has the answer to the problem.

I did the test and send a signal. Sound comes out through the slave amplifier. But Output and solo doesnt work.

I changed the three jfts just in case no result. This morning I removed them by bridging their sides and three in m1 and M2. I also cut the three loop cables... I ultimately made the FX loop mod and it didn't work either. Again to the mess: I cleaned all the FX loop pots and FX loop assignment and the two Jack consciously as well as the valve sockets and previously and this time to bridge with the wire and return the output knobs and only came back to life. I have not found a solution to this problem in English, German or Spanish-speaking forums, especially in Argentina. I guess this won't be a solution and it can fail again. But at least somebody's gonna help. I'll put this info in those forums I put this on the same question because I'm sick of a bunch of rock that comes out with trouble and says it's going to lead it to repair or do whatever it is and never posts anything like a solution or clue again. We need to be more collaborative. Thank you to everyone who helped me in this thread, as always 10. If it's still working for a long time, I'll tell you around. Hugs!

I really like your attitude. So many times problem is shared, the fix is not.

Can you please elaborate this part:
".. and previously and this time to bridge with the wire and return the output knobs and only came back to life."

Based on this description I'm not sure what the problem was but I'm thinking it was oxidised loop assignment pot contacts. I saw the post you made on Monday and since then my intention was to re-visit the schematic and try to make some sense of this but haven't had the time. I'd really like to understand what the culprit was. I have also Dual Recto and eventually it might have the same issue. Mine is maybe 2005-2008 model and I've never had a problem with it, which dramatically increases the probability that I will have a problem with it at some point.