Fender Bassman 100 red plating problems

[soundmasterg]

It looks like the problem with this amp was a bad tube socket on #4 tube. Once the screen ressitor blew, the socket must have been susceptible to arcing. I replaced the socket and everything is working great now. I plan to let it cook for hours and see if it is still keeping its bias, but assuming it is ok with that, then a bad socket was the problem.

Greg