I finally got hold of a Blaupunkt Rivera. Cabinet in very good condition. Said to be working. Close inspection showed the ferrite antenna to be broken, the fuse replaced with a thin wire and one resistor in the final amplifier stage to be overheated. Scematics and trimming instructions were included witht he radio.
This is after some cleaning
W761 was burnt out.
This look suspicious!
Below you can download info about the Blaupunkt Riviera 2640