Trying to identify which A2000 Version I just got

[1NOM155]

Kronos wrote:
@Tahoe

The "CR" identifier was never used on the A2000 (only CDTV and  A4000D AFAIR).

The mobo of West-Chester-version is labelled B2000, so thats where that came from  ;-)

Read this...

(This was the original A2000-CR (Cost Reduced) that I designed. - Dave Haynie (Commodore Engineer))

For more info see Link 1 and Link 2.

[1NOM155]

Clean it, and have a check on CIA chips.
Check too the jumper J301:

This jumper is closed to add a second internal floppy drive, open to leave the second floppy out of the main unit box. The Amiga expects an ID bit stream from each floppy drive; this lets it determine the drive type. External floppies have this ID circuitry on board, but as it's not an industry standard capability, it has to be implemented on the A2000 motherboard to save cost on internal drives. Leaving the jumper open prevents the Amiga from seeing the ID sequence.

If its necessary, you can buy here.