MODCOMP II Rescue Revisited...
RodSmallwood at mail.ediconsulting.co.uk
Tue Jun 5 01:37:02 CDT 2007
Well done that guy!!
What you have done is both the spirit and the essence of classic
You are to be congratulated on both effort and persistence.
"A shining light to lead others into the darkness of old computer
I was at DEC (UK) in the 70's and Modcomp would pop up as competition
from time to time.
Hasn't that front panel got DEC overtones?
Is there a keyboard terminal or screen with it?
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Lyle Bickley
Sent: 05 June 2007 05:07
To: General Discussion: On-Topic Posts Only
Subject: MODCOMP II Rescue Revisited...
A number of you probably remember me "announcing" in Jan, 2007 that I
had rescued a MODCOMP II/12 from a lab here in Silicon Valley. The link
for that is below (sorry, it's slow - the pictures are large).
After a lot of work cleaning up both the CPU and I/O chassis I began
checking out the system. It turned out that the I/O chassis was in
pretty bad shape.
I went back to the lab facility where I found the MODCOMP II - looked
through several more buildings - and found another lone MODCOMP II I/O
chassis. I went through the "salvage" process again - and finally picked
it up about a month ago.
It was in a lot better shape than the original I/O unit. And the really
great news - it was an identical configuration to my original I/O
After cleaning it up, doing all the usual capacitor, power supply
checking - I powered it up - and everything "looked" good - and no bad
I cabled up the CPU and I/O unit, powered 'em up - and to my amazement
the front panel controls seemed to work O.K.
I then did the usual hand memory tests - and core memory worked O.K.
every location I tested.
I then wrote a bunch of small diagnostics (in machine code) - and found
that I/O was not easy to code - but I did enough to check that the
console in/out ports worked O.K.
Today I loaded diagnostic monitors, and diags - and most of the system -
including I/O is working! The really good news is that all 64K (words)
of core memory passed the long manufacturing memory diagnostic - which
even tests for "hot cores" failing.
It's been months in the making this critter come alive - but it sure
feels great when the diagnostics tell you that you are on the right
Bickley Consulting West Inc.
Mountain View, CA
"Black holes are where God is dividing by zero"
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