Unusual DEC module: what is this thing?

From: Bob Shannon <bshannon_at_tiac.net>
Date: Mon Dec 15 11:35:32 2003

Does anyone recognise the following DEC module?

HIGH SPEED MOS MEM MAT MS1440 G401C

This is THE most unusual DEC board I've ever seen personally, and also
the most
beautiful.

This board has an extreamly early example of an LED in the upper right
hand corner
where a machined metal stiffener is used in place of the usual cast part
used on other
Unibus boards. This stiffener appears to have been milled out of an
extrusion, by
hand. Nylon hardware is used along with the more conventional eye-ring
rivits.

The outside edge of this milled part is stamped 'G401'.

This LED is made from a gold-clad machined metal case unlike anyI've
ever seen
 (including those seen on the LED museum web site). I can't see the
part number
on the case, but I'd bet its a Hewlett Packard. This LED alone may well
be worth
more than the whole module!

The IC's are an orderly mix of grey plastic, gold leaded Intel
P1103-1's, and gold on white
ceramic (with grey lead-frame traces) Intel 3207-1's.

Arrays of individual resistors form high speed DC terminators for the
arrays of 1103's and
3207's, and a small handful of TTL parts complete the list of chips.

The TTL datecodes suggest its from 1970.

The memory chips are not so easy to understand, the P1103-1's are marked:

P1103-1
0531

And the 3207's are marked:

3207-1
S183
B0536

Both feature a large 'i" logo to the left of the markings. Clearly very
early Intel parts.

I suspect that this ~may~ have been a 'live spare' for a PDP 11T55 I
once owned
and ran many years ago. If anyone knows what this board is, I'd love to
know.

I can try to get a digital photo made, but that may take some time. If
someone 'just
has to' own this board, I'm willing to talk. The overall condition of
the board is excellent
and very few of the decoupling caps have scratches from installation and
removal. The
unusual edge-stiffener also shows unusually little ware.
Received on Mon Dec 15 2003 - 11:35:32 GMT