svt-vr, green light, no sound

[bass bart]

Hi

I bought an svt-vr, about 3 months ago, and it's having some issues.
A rehearsal two weeks ago, I plugged in the amp, turned it on, let it warm up for a few minutes. When I flipped the standby switch, the led turned green and the ventilator started blowing, but there wasn't any sound, nothing, not even a slight hum.
I thought it maybe was that standby relais, that it didn't get enough voltage (I am from europe, so it works on 220 volts).
Back home, tried it, and it worked fine. So I thought I was right with the voltage problem.
Yesterday, I had another rehearsal, at a different place, where the amp always worked, but this time it didn't. I tried it later at home, and it is doing the same green led no sound thing.
It is still in warranty, so I could just send it back, but it will be gone for a while if I do so.
My question being: does anybody here had the same problem, or knows what might be the problem. It would be kind of useless to send it back, if it's a small problem, that I can fix myself (I study electricity and have worked with voltages of 400V+ I know the danger of it)

Thanks
Bart

[anderbass]

Did you try both input channels?

Something easy you could try is plugging your bass into the Power Amp In jack to bypass the preamp section. It wouldn't play as loud but If you get some sound this way you'll be fairly sure the problem is somewhere in the preamp section and maybe even just one of the preamp tubes.

[bass bart]

Thanks for the reply anderbass, but I hope I fixed it.
I opened the svt up and checked if all the tubes, and the connectors were firmly in place, and looked around if I didn't see any cold or broken solder joints, I didn't see anything abnormal. But it worked again when I closed it up. I hope it stays that way, if not I'm going to try the power amp in jack. I tried the different channels when it didn't work, and they gave me nothing either, and of course different bass, cab, cables, etc.

[bass bart]

Ok, let's report back.
The first rehearsal after I thought I fixed it, is just stopped working again, in the middle of a song. Back home I take out my epi valve jr, since it got just one preamp tube, I tested all the tubes, one 12ax7 appeared to be broken, it flashed while powering up, and gave me no sound. So swapped out the preamp tube and all was good. 2 rehearsals later, it cut out again, channel 1 became really silent, if I turned up the volume you could hear some sound coming out. So I try channel 2, which appears to work. During the break, I shut the amp completely off, it rested for about an hour, and channel 1 worked again. After playing another 2 hours, I perceived it became a little bit more silent and less full sounding.
A day later, I turn it on to practice a bit, and it makes this huge crackling noise when on. Tried swapping various tubes, and after swapping V3 out, it sounded great again.
Because I'm curious, I try the tube from V3 in the epi valve jr, and it sounds normal.
So the problem is in the ampeg.
Does anybody has any idea what it might be?