Ongoing excavations - PDP-11/20 bits

From: Ethan Dicks <ethan_dicks_at_yahoo.com>
Date: Wed Oct 27 00:10:16 1999

For those at home who have been following my relocation of stuff from the
basement of my former boss, I have *located* the 11/20 chassis. It has
some backplanes in it but no power supply. It is sitting on a BA-11 that
looks suspiciously of the same era, but too far down in the stack to get at
just yet. If so, then I have a CPU bay and two BA-11 expansion boxes, enough
FLIP-CHIPs to probably reassemble the CPU, several sets of 4K MM11-E boards
(at least one core plane is in the hands of a former cow-orker, now in Boston),
two power supplies total, a diode-matrix boot board, several peripheral cards
and plenty of modern stuff to make this thing boot. I do also happen to have
the original 1970 PDP-11 handbook that came with it, but no prints.

Does anyone have a module layout for the 11/20? BTW, since this has come
up recently, from the handbook, page viii

    The PDP-11 is available in two versions -- PDP-11/0 and PDP-
    11/20. The basic PDP-10 contains 1,024 words of read-only
    memory inconjuction with 128 words of read/write memory and
    the basic PDP-11/20 includes 4,096 words of read/write memory

I take it that the -11/20 has an MM11-E backplane in the CPU box and that
the -11/10 comes with an MR11-A braided core ROM unit and an MW11-A "Wordlet"
core board.

After this is entirely excavated, I would expect that I could use an
additional H720 PSU, but since I have the specs (+5V _at_ 12A, -15V @ 10A,
+8RMS (unreg) _at_ 1.5A, -22V (unreg) @ 1.0A) that I could fake it with
modern equivalents.

-ethan



=====
Infinet has been sold. The domain is going away in February.
Please send all replies to

  erd_at_iname.com
__________________________________________________
Do You Yahoo!?
Bid and sell for free at http://auctions.yahoo.com
Received on Wed Oct 27 1999 - 00:10:16 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:32:34 BST