UNIBUS Mystery Board ID

From: Ethan Dicks <erd_6502_at_yahoo.com>
Date: Thu Mar 28 13:07:00 2002

--- Jeffrey Sharp <lists_at_subatomix.com> wrote:
> This hex-width board was found sitting in a UNIBUS backplane. It looks
> like
> it may have more than two PCB layers. The metal handle, where the board
> number is usually stamped, is unmarked; no board number is stamped there.

Typical of non-DEC boards. If you bought handles from DEC at all, you
bought the generic (unstamped) ones. Some people engineered their own
fastener (EMC? Emulex?) for later designs to reduce the amount of money
per board that ended up in DEC's pockets (reducing manufacturing costs).
We always used DEC handles; our volumes were low enough that even at,
ISTR, $20 per handle, it wasn't worth us designing our own.

> On the front side, top left, is "AD413A MADE IN USA"...

Hmm... "AD"... Analog Devices? Anybody else use "AD" in their part

> There are two 50-pin BERG (maybe formatted Pertec) connectors
> at the front top.

Not necessarily - most DEC and 3rd-party peripherals used 40-pina
and 50-pin BERG connectors (40-pin: DMF-32, DL-11 and other serial
interfaces, RL11, COMBOARD serial _and_ parallel ports, etc. 50-pin:
Emulex serial cards (dual DZ-11 or DH-11 emulators), TU-80 (Pertec
interface), a real DZ11, RQDX[123], SCSI, etc.).

I'm not saying it _can't_ be a tape interface, but I am saying that
2 x 50-pin-BERG does not a Pertec interface make.

> On the back of the board, at the top right, is "MRX42 200255-02"...

No idea what that is.

> Google has returned nothing. What have I here?

I studied the pictures. A scan of the board near the BERG connectors
showing the part numbers of the interface chips for the external
device might be illuminating. I do not know what was commonly used
for tape devices, but it might help to establish if this is some
kind of lab I/O module or tape controller or what. Since there are
no 40-pin (6402s) or other ICs larger than about 20 pins (like a 24?
pin Motorola UART), I doubt it's a serial card.

You do, indeed, have an enigma (not an Enigma ;-)


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Received on Thu Mar 28 2002 - 13:07:00 GMT

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