Late-model Hercules card

[Jules Richardson]

I've got a full-length ISA (although the last 4" or so is bare PCB, not 
even any ground plane) Hercules card here which seems to have been built in 
1990.  On board we have lots of TTL glue, a pair of 50464 RAM chips, a 24 
pin "Hercules font ROM", a 6845, and a 40 pin HG61H15R81P IC. Card edge 
just has a female DE9 connector.

Oh, FCC ID is "EW65T5HERCULESTAN". No obvious model number.

1990 seems quite recent, given that we were into SVGA territory by then; 
sure there were some CAD applications which would make use of an additional 
video board, but the market must have been small. Based on the above (and 
to save me having to trace pins) can anyone confirm that the board is 
compatible with the original Hercules card and will hook up to an MDA 
display? Given the date I just want to check that it's not one of their CGA 
or EGA compatibles.

cheers

Jules