Dec boards- what are they?

[Pete Turnbull]

On Jun 7 2005,  8:56, Tom Peters wrote:
> I figured out what most of my stray DEC boards are-- DLV11 and such.
These
> two baffle me. One might not even be a Q-Bus board like the rest.
>
> Mystery board #1:
>
> Pull-tab numbers: M7721 (Magenta)
[ .. ]
> Terminator? For what? It's cut for Q-Bus, but it's short.

Boards for Omnibus, Unibus, Q-bus, etc are all built to the same basic
dimensions, so you cazn't tell that way.  As it happens, that board is
none of the above.  It's part of the internal logic of an LA30
(Decwriter).


> Mystery board #2:
>
> Unpopulated (except for U8, the only 28 pin IC on board, a Motorola
> MC3242A) in other words, empty sockets. Most of the sockets are 14 or
16
> pin, except for one 8-pin. 16 of the 16 pin sockets are laid out in
two
> neat rows, which makes me think of memory. There's voltage inverter
or
> charge-pump type chip at U20.
> Markings: Solder side: "Copyright 1978 by Heath Company"  "85-2195"
  "100478"
> Component side: "81-2195-3" and "ADDRESS SELECTION" next to 8 jumper
pads.
> Gotta be a Q-Bus memory card, right?

Yes it is.  It's for an H-11 system.  That MC3242A is a refresh counter
and address multioplexer for 4116 DRAMs.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York