What computer are these 5 NCR boards from?

[rorypoole]

I have got 5 NEC boards as they looked interesting and did not cost too much, I like the fact that all but 1 have test points at the top end on the card so they could be tested when in the computer and working.
the left board is labeled (detail 390c4782) (390c2131 front 390c2130) (memory grounder) uses 645000 transistors?

the middle board is labeled (390?2469) (national) (390c2465 front) (inverter) and uses ncr 404 transistors?

the left most board is labeled (clamp cable driver) (390c2478assy) (390c2475 front) (390c4768 detail) (national) and 646006 transistors

 

[rorypoole]

right most board is labeled (detail 095c0003815 decode assy 095c0003814) and some NCR 6460006 transistors

left most board is labeled (438c125) (logic latch assy) (issue) and uses NCR 404 transistors but the board has been hacked, its missing 5 small carbon resisters, and 4 large power resisters, I would love to repair this board, I can easily replace the missing parts but finding parts that would look right will be tricky

 

[rorypoole]

some more pics of the cards, damage and the connecter.
what computer where these used in? and what is the type of connecter, and where can I get 6? what year where that made?
any help welcome, and trade also welcome if its to go to restoring a computer.