Peavey Ultra Plus just having some various re-soldering done so it could work without cutting out or changing volume occasionally. Needed a quick fix so a touring band could continue their saga.
Cracked solder connections on speaker jacks and impedance selector switch were the main problem. You might as well re-solder the FX loop jacks while you’re in there. And clean the switching jacks with contact cleaner for a better chance of it not potentially becoming a next problem. Can’t think of any other amps that have preamp tubes inside the chassis other than this amp and 5150s. Seems like a strange idea since tubes get hot and you would want to minimize heating inside the chassis because it reduces electrolytic capacitor lifetime. Wonder why they do it. Maybe it makes the build easier in some way. It is nice how they are snug fit with the foam on metal bracket. The PCB the preamp tubes are situated on is kind of flexy. That’s not good either but it has to because of the pushback from the foam. But I wonder if the pre tubes are inside the chassis like that because it’s an extremely high gain amp and that internal mounting style with foam bracket might reduce noise from microphonic preamp tubes more compared to the typical mount style where tube sockets are screwed or riveted to the chassis. I’m into the vibration reduction but not the extra heat in the chassis, especially since those preamp power supply caps are right next to the preamp tubes (under the grey PCB interconnect wires that connect main PCB to preamp tube PCB). Here is Peavey Ultra Plus schematic and parts list in all 13 pages of it’s glory. It needs a couple extra pages so it could include the circuit design for making the channel switching work in tandem with the footswitch and with a bunch of other relays and LEDs that change the color of the Peavey logo on the front panel when you switch between the three different channels. Not hard to get schematics from PV.