Probably 2, maybe 3 years ago I scored an incomplete "project" from Reverb or Ebay, It came wrapped in a decent Bassman head, with an original Bassman chassis, black nameplates (might be original), all new pots, and what looks like a prewired board installed. Xformers included.
Everything but the board was used as a donor to build a Bassman hybrid from Circuitrix. (Turned out great, lots of spaghetti, one of my gigging amps)
I think I almost ID'd this board way back then, with a Google Image Search, but I didn't save that result. On a whim & and prayer, if anyone can narrow my search parameter it would warm up my February. The bottom most turrets haven't been used yet, or by design, so that throws me off track a bit.
I retired this fall and there's projects a-poppin'
Best wishes and thanks to all,
Gary Lee