This is a 6123 / 6125 Tape Streamer PSU listed in my parts reference as PCB 6123/6125 POWER SUPPLY.
More on this PCB in due course once it leaves ‘The Shed’ and has undergone bench testing.
005-018496 – 6123/6125 PSU
Data General Nova, Eclipse, MV and AV
Data General Preservation and Restoration