This amp had been converted to use EL34 finals. Unfortunately, the solder joints on the new screen grid stoppers were cold. I was able to just pull them off the board.
I installed new screen stopper resistors, reflowed a few questionable solder joints, and threw in a set of Winged C 6L6s. I also auditioned a ton of preamp tubes and eventually found a set that reduced the level of noise in the amp.
The owner built a really nice head cab for the amp. If "combo" wasn't printed on the back panel, one would never know that it wasn't original.