Choose Advanced Search, enter your desired search terms and check "Completed items only".

That's how had I looked for it, and not a single Blaupunkt PA2100 shows up in whatever date-range ebay retains for completed items. There were a pair of Harmon Kardan PA2100 amps, but those are not at all the same thing.

I'm going to ask Stu at Eutronics if he'd like to have a go at fixing mine...

tanstaafl.