Valve Jr Issue w/ No Sound...Baffled!!!

[KP Capehart]

Hey guys,

 

First post on here...bit of a back story, so please bear with me as it's pertinent. I've had a VJ for several years and about a yr and a half ago (at a gig) the sound started going out and eventually it just stopped producing sound at all. When I got home, I first replace both tubes thinking that might be the issue...no change, no sound. Tried yet another set of tubes, issue did not change. I opened it up, looked at the PCB for any charring or cold solder joints, nothing found. Kinda gave up and purchased a slightly modded AC15 for cheap and have been happy with that ever since. This week I decided to mess around again with the VJ and got excited about tracing down the issue and modding. I have been doing tons of research and one post directed me to check the fuse coming from the transformer. I opened that up, wire brushed the connectors and fuse, reassembled and yay...it worked!!! Replaced 4 resistors (R1,2,4), removed R7 and clipped JP1. Amp sounded amazing; really started to sing and open up. As I was tested, about 15 min into playing the sound started going out (like it did when it died before) and eventually, no sound again. I then decided to replace some more parts (per tone mod research) hoping a component was the issue. Still no sound!!! I've replaced C1,2,6,9. Still no sound at all.

 

I know it's a shot in the dark, but has anyone here experienced these symptoms or anything close? I don't know if it's the OT or another component giving me the issue. I'm a novice electronics guy, but know a bit about components and their functions, soldering, etc. I'm baffled because it worked fine and then just quit on me again. Hoping that can shed some light on the problem. If anyone has any advice as to what I can check, replace, etc I would be grateful. I was really digging the tone before it crapped out on me. Would love to have this as a recording and backup amp.

 

Thx for your help!