Peavey classic 30 tube amp no sound.

[guysilvermt]

I just cleaned the tube sockets and the pots on this amp. It had been popping and crackling like crazy, but this fixed the problem and it was sounding the best it has since I bought it. I was stoked then after playing for 10 minutes of bliss and all sound was lost, then smoke! I unplugged it removed the tubes and pulled out the board. To get at everything you have to unfold it like a taco! Its not something I want to do if I don't have to because I noticed a blown capacitor that would be reasonably easy to replace without doing any of that. If you look at the attached schematic its C39 my question is would this capacitor being blown make the amp not produce any sound at all or should I suspect other problems? I don't want to have to unfold the board but I don't want to wait for parts and not fix the problem either. I don't see any other visible issues

 

[daschnoz]

Did you check for continuity in F2? If the cap blew and shorted while doing so, it is possible that the fuse is blown. I know, it's a "well duh" kind of question, but it's often these simple things that are overlooked.

If the cap puked a mess all over the inside the amp, you could have a small piece of foil shorting something out. You may need to open the thing up anyway.

 

[Brian Roth]

I'm not a guitar amp guy but see some things to check.

Is fuse F2 blown? Check it out of circuit with an Ohmmeter. Is it the correct size...1 Amp fast blow? Reason for the last check is to make sure it hadn't been "slugged" with an over sized amperage value.

(while writing this I saw @daschnoz said the same thing..lol)

Test the diodes CR7/8/9/10, especially for short circuits.

Does C40 "look" ok? C39 and 40 are subjected to the exact same voltage, so both could have problems. Or, perhaps C39 just had a bad day....

Bri

 

[Brian Roth]

After I replied, I signed off to watch the 10:00 local news and weather, and I had two thoughts for the OP.

You DO realize that you're poking around in a very high voltage section of the amplifier. Do you know proper safety procedures?

Second....IF F2 is blown AND it was the proper rating (1 Amp fast blow) was the wire inside the glass cylinder merely broken, or had it left a "poof" of black material inside the glass cylinder?

Bri

 

[pucho812]

Carful with that amp Eugene, you don’t want to shock yourself.

 

[NoisyIndividual]

If C39 is blown as you say, you really should replace the identical C40 as well.
Then check the 4 diodes are OK and change the fuse F2 anyway.