Peavey Mace VT red plating and arching...ouch!

[iwantmypie]

Hello All. Long time no see (that's a good thing, means my amp hasn't had any problems until now)

I recently encountered a problem with a red plating power tube. Swapped the tube to another position to see if it was a faulty tube or the problem stayed with the socket. Problem didn't follow the tube... I tried some contact cleaner to no avail.

Now I'm having a problem with the outer tube next to it occasionally showering internal sparks as soon as I flip the standby switch. This also comes with a terrible noise, worse than the red platter. I've only been running 4 tubes and this is the order of the "bad" sockets as if looking at the amp from behind.

X U U U U X

The red U is the red platter and blue U is the sparker. A few years ago I did a couple of mods with adding an adjustable bias, increasing the size of the screen grid resistors and adding a choke in place of the power supply resistor. I removed all of these mods and put the amp back to stock just to see if it would help, it didn't.

I was trying to see if I could retention the pins with a dental pick but I'm having trouble getting it to fit in there.

Question is, how do I remove the tube sockets/PCB? It doesn't seem as if the board is being held down by any screws. Will I have to desolder every socket to be able to lift the board? I'm worried about ruining traces and putting too much heat on the board trying to remove the mounds of old solder but it seems necessary.

I'd like to be able to rule out a physical problem with the sockets before I move on to further trouble shooting. The tubes definitely slide into the old sockets with little resistance. The red plating occurs so quickly that I'm finding it difficult to check test point voltages while the amp if not in standby.

Thanks.

[Enzo]

If I recall, the tube socket board is rivited in. 1/8" drill, drill them out. Then reinstall after repair with a pop rivet gun from any hardware store.

You have a sparking tube? Get rid of it. It is next to the red plater? It could actually be responsible. The two together are wired together, and if one tube shorts internally it could wind up killing the bias on its mate. Pull all the power tubes, and stick just one in the amp, in that red-plate socket. Fire it up. Does it still red plate or does it now behave?

[iwantmypie]

If I recall, the tube socket board is rivited in. 1/8" drill, drill them out. Then reinstall after repair with a pop rivet gun from any hardware store.

You have a sparking tube? Get rid of it. It is next to the red plater? It could actually be responsible. The two together are wired together, and if one tube shorts internally it could wind up killing the bias on its mate. Pull all the power tubes, and stick just one in the amp, in that red-plate socket. Fire it up. Does it still red plate or does it now behave?

Enzo, I tried what you suggested and the red plate socket now behaves. Think I'll buy some new tubes and report back.

I was also able to get an x-acto knife tip to fit in the sockets so I was able to retention the pins but this set of tubes is about 4 years old now running at around 70%. Think I'm going to leave my amp back in stock form and see if I can get some serious life out of the next pair of tubes.

Thanks.