The drain pump shorted out, a common problem on this model. Replaced that.
The short blew the ACST (a kind of a switch) on the main board, a common problem on this model. Replaced that.
The damage was more extensive on main board than I’d hoped, an additional relay is probably bad and an unknown number of other components. Replaced that.
The new main board fails to communicate with the inverter board, a common problem on this model.
I’m going to borrow a DMM to troubleshoot, but at this point I’m stuck between dumping more money into it, or returning both the new main board and the drain pump which have not seen action yet, and just buying a new washer.
Washing machines are scams. Every company uses a raw aluminum spindle to support the drum that is designed to react with detergents and break after a number of washes. It takes hours to replace, if you can find the part. Then Bosch started sealing the drums with welded plastic so users could not replace them.
They’re taking too many hints from the printer industry