7 Jun
2005
7 Jun
'05
10:28 a.m.
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