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

Matt Patoray mspproductions at gmail.com
Tue Jun 14 08:21:29 EDT 2016

This is great to see, just a first step in a VERY long process, but
everything has to start somewhere. Keep up the good work!

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.

Matt Patoray
Owner, MSP Productions
(330)718-3064 (mobile)
mspproductions at gmail.com
KD8AMG Amateur Radio Call Sign

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