What Could Be Wrong With My Delta Blues?

[googoobaby]

I have a Peavey Delta Blues 1x15 that is acting strange. At power-up it works fine, but as time passes, the amount of amplification decreases until the output is just a faint tinny thing. I can hear the usual unvarying slight amount of background noise as this happens. I replaced the power tubes with new ones and it still acts the same (the old ones were about a year old). I've individually swapped the preamp tubes with known working ones from my Rivera and see no difference either. I just set the amp aside for a while and used other ones, but I'd like to get the Peavey working again.

Any advice would be greatly appreciated as I'm quite far from a decent repair shop and repair costs would be a significant fraction of what the amp is worth.

[teefus]

how long have you owned the amp and was there an event (dropping, etc) that preceded the problem? pv classic series amps can be prone to cold solder joints and broken jumpers. there are 3 circuit boards folded into a "c" shape with jumpers between them. do you have any experience trouble-shooting and repairing tube amps? be careful about probing around in there.

[googoobaby]

I bought it off of eBay (yeah, I know...) and had it for about a year without any trouble. It was my practice amp, so it was never moved much or abused. I do appreciate the caution as I don't want to curl my hair and toes though my own ignorance. I've done a tiny amount of troubleshooting on my Rivera, but that made a lot more sense inside (despite being a PCB amp). I'm loathe to crack open the Peavey.

[pbdog]

The power tranny just went on on mine. Same symptoms. $65 @ peavey parts.

[googoobaby]

Thanks!