The PSU was defective - but it was easy to repair that.
Who in the world owns two HP-machines? ;-)
The differences to the Prototype (@ left):
Keyboard in beige/green color, sticker instead engraved Commodore, plug in the monitor-power-cable, only 128kB RAM, three 2764 ROMs on adapter-board
It's made in germany
I have to clean it!