I am a recent ower of a Marshall Origin 20, which I got in July. I've really enjoyed the amp until I plugged in last night and got out absolutely no sound out of it. I couldn't figure out why, as nothing as happened to it and it worked fine two days ago. I took it apart to do some trouble shooting and found that when I have all the knobs max'd and output on 20 watts, I can hear a whisper of my guitar signal (nicely saturated, presumably by the preamp tubes) through the speaker. This sound is affected by all of the knobs. However, if I plug my guitar directly into the return of the effects loop, and activate the effects loop I get no sound whatsoever; no guitar, no hum, nothing. Because of this, I'm sure my speaker is not the problem. These things led me to think it was a power amp section issue, so I went down and purchased a new set of matched EL34's, threw them in there, and nothing changed. I'd really like to know if there's anything I can do to fix this, because this amp is not even a year old and I should not be having these kinds of problems with completely normal bedroom use.
Having issues with a clients amp, seems that after a retube that i did, he was playing and after about 30 min, it gradually started losing sound and then cut sound completely. I did the re-tube myself, and biased it properly and i was able to play it for about 40 min with absolutely no issues. List of troubleshooting steps i have done:
tried a different speaker cable
tried a different guitar cabinet
tried a different guitar and guitar cable
tried the old tubes, additionally bought a 12ax7 and tested each pre-amp tube
tried a different power source
Have tried different power tubes
have checked and replaced the fuses
Now this is what i am THINKING is the problem, I think it might be something with either the heater curcuit fuse, or i think it's called a BRT1 Rectifier? I did alot of research and it seems that the people having MY issue, explain the same symptoms of what i am having.
Now i have to make this clear, I AM NOT A PROFESSIONAL TECH, just a guy helping bands out with tech stuff that they don't know how to do. So any help is appreciated.