Right channel dead after working for years

[Pharane0]

Hello I would like to ask for your help please.

My right channel died spontaneously after having the amp working perfectly for a year or two.

I did the volume mod to the volume pot with 75k / 33k resistors two weeks ago. Worked flawlessly again. But then one morning my right channel was dead. I unplugged / replugged everything, checked that it wasn't my dac with another amp (it's not my dac). The Crack worked perfectly again for a day, with both channels working again but then today it seem to have died this morning AGAIN for good this time.

I swapped the two tubes for other ones, same problem, the right channel is dead.

I did the resistance check from the manual, before plugging it in to check to voltages, and I saw that 4 measurements were faulty:
-7
-9
-B3
-B6
These four are supposed to read 2.9kOhm but read either super super high MOhm or even "O.L". I'm not an electronics expert and I'm quite lost with this amp. Do you guys have experience with these and know what it could mean please ? Since the resistance were off, I didn't perform the voltage check. The red leds are all lighting up when the amp is ON and the tubes are glowing.

Thank you for your help.
Alexis

 

[Paul Birkeland]

You have a Speedball upgrade installed, so 7, 9, B3, and B6 are not going to be 3K.

You will need to post your DC voltages in order for us to understand what's going on.

 

[Pharane0]

Performed the voltage check today. Everything is within the spec written in the manual. Did the measurements for the speedball and the crack. The only thing that slightly differed was OA / OB on the big board at 110V instead of the spec [75-100] and on the crack terminal 2 and 4 are at 190V instead of the spec [170]. My AC voltage is 220V btw. All leds and tubes are glowing. I don't know what's wrong with my amp. Sometimes, after measurements and me hooking it back up to my dac it's working again and then, the next morning when I turn it up it's dead again. I don't understand.

 

[Paul Birkeland]

That would tend to indicate a solder joint or two that aren't 100% solid. You can poke around the circuit while it's running with a wooden chopstick to see if you can find a spot where pressing on it causes the circuit to stop working properly. It can help to have music playing and a cheap pair of headphones plugged in to be able to pick up on this more clearly.