No, all works, reverb bit microphonic.
Wanted to lower to 12AT7 to see how it works.
Was just about to say: looks like V5 (T7 not X) drives the reverb and 1/2 of V6 (X7) recovers. Trem uses the other half of V6.I lied to you. I just pulled up another schematic and all of V5 is reverb. It's the driver amp. 1/2 of V6 is the receiver and the other half of V6 is tremolo.
I've never tried it, but I don't think 12AT7 will work in the tremolo. I don't think it will have enough gain. V5 may work as a reverb driver, but it is certainly going to be different.
You're not going to hurt anything by trying it.
I would re-solder the 3 ceramic disc capacitors to the left near the input for starters.Sorry to dredge an old thread, but just recently acquired a YGM-4 and the tremelo is not working at all. Nothing straight off the front of the amp, nor through the footswitch jack. Footswitch works as I tried it in the reverb jack and it turns on/off as it should. I noted that all tubes are glowing and the amp is functional aside from no tremolo. Would be nice to have it working, but if it doesn't (or can't without copious $$) then I can live with it for now. The tremolo is the pot to farthest right. I am posting bigger images than I normally do see you electronic experts can see the parts easier.
Am I close?...totally thanks to your pic.Also I see what looks like a wire coming off the board. Hard to see, so I'm not sure.
I'm assuming this is what caught your eye?I would re-solder the 3 ceramic disc capacitors to the left near the input for starters.
Other than a meter, which I really don't know how to read unless I am following precise instructions. I can't read schematics either. I literally know nothing about electronics. If it isn't something simple, I won't even attempt. I don't want to destroy something trying to repair it.What test equipment do you have? Are you able to read and translate to the build from the schematic?
One odd thing I see is at the speed pot, the resistor tied to the ground wire and the center pin of the pot. This is not factory, so someone has been mucking about inside the amp.
Also I see what looks like a wire coming off the board. Hard to see, so I'm not sure.