Actually I think there's THREE green ones but I could be wrong. I don't
think I've ever looked to see which models are one my 9845s.
I was only aware of a total of 3 different monitors for the 9845. There's
the standard monochrome one (could this take an internal graphics board
as an option?), the enhanced mono one (98780) and the colour one (98770)
These monitors, of course, contain much of the video display circuity.
The ehanced mnonochrome monitor must contain around 200 chips, including
an HP custom thing in a 64 pin DIL package with heatsink pillars that
bolt to the side of the case. It is clearly an address generator for
doing things like line drawing.
I am told the colour one is even more fun inside, with a board of AMD
29xx bitslice ICs. Alas I don't have one, and there's little chance of me
finding one (it would have to be local to me, there's no way it could be
shipped).
-tony