[vcf-midatlantic] Univac, our first real work!

Bob Flanders bob.flanders at gmail.com
Mon Jun 13 16:24:10 EDT 2016

Very cool. Reminds me of the AN/UYK-7.

As you deal with problems (like gooey rubber, etc.), you may want to check
out this blog:


Carl Claunch has ad to deal with a lot of these types of problems while
restoring an IBM 1130. You may find some similar items in the blog, or ask
Carl if he has dealt with similar problems and his solution.


On Mon, Jun 13, 2016 at 4:01 PM, Evan Koblentz via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> Hey everyone,
> 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 outside.
> 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. :)
> https://www.youtube.com/watch?v=SQCSGF5Suxo
> 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 parts-swapping.
> 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.

More information about the vcf-midatlantic mailing list