The Nimbus PC was redesigned at the sametime as the 286 and 386 units were introduced.
"Packed into a neat, low profile no bigger than a video recorder."
The redesign removed the short lived ROM Cartridge slots, drive power was via mainboard connectors, not direct from the PSU. Memory IC's were changed to mb81c4256-10p with 1mb onboard as standard.
Gone was the Nimbus specific 84 key keyboard to be replaced with an industry standard 102 key PS/2 keyboard.
During the transition period RM included a letter in with the order to advise customers of the change.
The chassis was a complex compartmentalised plastic arrangement:
Other views of the chassis:
The PSU was redesigned and swapped its metal enclosue on the old model to plastic:
The redesigned mainboard:
and from some other angles:
Here is the completed case: