[vcf-midatlantic] Univac, our first real work!
joe.herdler at yahoo.com
Tue Jun 14 08:16:06 EDT 2016
What model TTY do you have? If it is a 28, I know a former TTY / Western-Electric engineer who works on those and restores them to life. He restored my TTYs and might be willing to travel if asked nicely.
I have three 28 units in my own collection all running on a three way loop with a tube based FSK generator/reader. (The 28 series was the flash-Cadillac of the TTY world.)
Consciousness affects the medium. Think happy, be happy, and happiness will follow you.
From: Evan Koblentz via vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org>
To: vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org>
Cc: Evan Koblentz <evan at snarc.net>
Sent: Monday, June 13, 2016 3:01 PM
Subject: [vcf-midatlantic] Univac, our first real work!
Our workshop this past weekend had the usual highlights -- we repaired
all sorts of 8-bit stuff, monitors, did some programming, enjoyed plenty
of nerdly shenanigans -- but by far the highlight was when Duane C. and
Bill Drom. told me the Univac 1532 I/O console (paper tape + Model 35
teletype) was ready for its first power up!
Background: We acquired a complete-ish Univac 1219-B mainframe about six
years ago. One tape drive was on display for a few years in our old
museum, and much of the full system was on display as one of the VCF
East shows, but mostly the computer lived in our warehouse. That changed
this spring when we opened the new museum: its double doorway enabled us
to put the computer on permanent public display. We cleaned it on the
Bill Drom. and Duane, who both used this model of Univac in their Navy
days, jointly approached me ahead of this past workshop and asked if
they could start technical work by modifying one of the console units
for a modern power supply. They assured me it's safe and easily
reversible to the original configuration, so I said yes.
A summary from Duane about what they actually did:
>> The +/- 15 and -4.5 switching supplies fit in the space we removed
the 400 Hz. transformer-diode assembly. The -28 volt supply wound up in
the air channel at the bottom. We bypassed the 400 Hz. power on relay
and have to turn on with a external switch. Does anyone have a feel of
what 60 Hz. voltage would pick a 115 Volt 400 Hz. relay? if it is a
straight inductance problem it would be 17.25 volts . We left that for a
future visit when we have a variac to play with. We did not have time to
trouble shoot all the problems the 1532 had. at first the logic was so
crazy that we put in a logic drawer from another unit. turns out the
display unit was missing cards. The rubber on the reader capstan had
turned to a gooey mess and peeled off onto the tape we tried. If none of
their consoles has a usable pinch roller they will have to send it off
to a service that does that sort of thing. Maybe we could try some of
the liquid rubber that is made to dip tool handles in. The punch is
punching extra bits. The oil on the TTY was all dried up and at first
the TTY would not do anything. It took about an hour of oiling and
moving stuff by hand until it gradually came to life. The tape chute has
the bracket that holds it up under the punch broken so the tape gets
snarled coming out of the punch. It will be easier to swap out the tape
drawer than to try to swap the chute. I put in a new one once and it
took me about a hour to figure out how to get it in without bending it. <<
Saturday night, when only the power supply was installed, about a
half-dozen of us went into the museum room and observed the first
power-up. Here's the video... well actually it's take two; the first
time I idiotically recorded it with my phone in portrait mode. :)
We have three more of these console units in storage, along with one
extra CPU and one extra tape drive, which is all very helpful for
This is an exciting milestone for us! I'm going to send a note to the
nice people who gave us the system as well.
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