----- Original Message -----
From: "Tony Duell" <ard_at_p850ug1.demon.co.uk>
>
> Are you sure it's _anything_ (rather than just being a few spare
> flip-chips)? From what I remember all you have there are a few gates (and
> maybe FFs) -- there's no M105 Unibus address decoder, no M782/7820/7821
> Unibus Interrupt logic, no bus drivers or receivers. I can't see it's any
> complete device, unless it was a bit of logic hung off (say) an DR11.
> Does the backplane have an official DEC sticker on the side of the metal
> frame? If so, what does it say?
>
This particular machine did come from a government testing lab, so it
probably had some custom stuff in it originally. The machine seems to work
fine without the flip chips installed. I looked up the M660 in the 1973-74
loginc handbook and identified it as a 'Positive Level Cable Driver'. The
description (from the book) is: "The M660 Cable Driver consists of three
NAND gate circuits each of which will drive a 100 ohm terminated cable with
M series levels or pulses of greater than 100 ns." The other cards, as you
said, are just various logic gates:
M112 - Nor Gate
M113 - Nand Gates
M116 - Six 4 input NAND Gates
M205 - General Purpose Flip Flops
Received on Mon Aug 19 2002 - 18:29:01 BST