9 Sep
2007
9 Sep
'07
11:13 a.m.
On 9/9/07, Jerome H. Fine <jhfinedp3k at compsys.to> wrote:
Naturally.
Ethan Dicks
wrote:
I have a VT103 up in the attic...
Probably the first step is to add 22 bit address support
to the backplane. That requires a steady hand with a
soldering iron and probably is best done with old lead
solder since the added wires will be attached to solder
points that already have lead solder. In any case, almost
no additional solder is needed. About the best wire to use
is wire-wrap since it is thin, but very sturdy. Keep all
the insulation except for the 6 mid points where the
wire must be soldered to the existing backplane. 4 wires
with 8 connections each are all that is required. If you
require help locating the solder points, I can look at one
of the VT103 backplanes that have been modified. Fortunately,
DEC never attempted to use a PDP-11/03, so the 4 address
lines at not attached to anything else - like power.
I have upgraded backplanes in the past. I found the easiest way to do
it was to use recycled DEC backplane power strips - bits of thin metal
that have a small (pin-sized hole) alternating with a larger hole that
misses the next pin. I recovered some from a PDP-8/L that arrived to
me with broken backplane. DEC used to sell it as a separate item for
customers who were working with foundation modules and such. I don't
know where I'd get it now.
... However, an RQDX1,2
was out of the question since they require 6 Amps for
the 5V. An RQDX3 is probably OK when used with a quad
CPU like the M8189 or the M8190 (since there are no
boot ROMs on any RQDXn controller). I guess that you
could type in a boot program (if you don't do it too often)
using hardware ODT - it takes about 5 minutes.
I was already presuming a SCSI interface.
Either a dual or a quad KDJ11 can be used. Almost
EVERY
quad KDJ11 is really the same as a PDP-11/83 except for
the 18 MHz crystal. And since you can't use PMI memory
without further modification of the first 2 slots to add
ABCD like the first 3 slots on a BA23, it seems that you
are stuck with an ordinary PDP-11/73.
True enough. I was more thinking of the advanced processors (11/93?)
for any onboard memory, not for PMI.
Most VT103 systems came with a paddle card that was
intended
to be used with a DLV11-J and a dual PDP-11 Qbus card. The
paddle card connected the terminal and keyboard to the 4th
channel on the DLV11-J that was then strapped as consol
and the normal 25 pin serial connector on the back could
then be connected to a second serial channel on the DLV11-J
(and probably sent to a serial line printer).
I do not have this card, but do know about it, and have been looking
for one, casually, for 20 years.
Since both replaceable media drives can also
be attached to a PC running E11...
We work in different worlds... I'd be doing any off-line prep work
with Simh and Linux.
Can I answer any other questions?
Since I'm not likely to be attempting this for a year or two (after
getting back from another winter at Pole), I'll probably ask questions
as they come up. For now, though, I can easily put together a KDF11
system, so I'll probably start there. I was just interested in what I
might need to put together a SCSI-based KDJ11 system with 4MB.
-ethan