In particular I'd like to know what crt controller was
used in the Rainbow. Grassy arse
Not a guru by any means, but anyway...
The motherboard video system (which was monochrome text only, and not
suprisingly similar to a VT100) used the VT100 chipset. The DC011 video
timing chip and the DC012 video controller.
The graphics option card, which produced an analogue RGB colour output,
used an uPC7220 graphics processor with lots of glue logic round it.
-tony