[vcf-midatlantic] That UNIVAC part from Grabbe -- update!

Evan Koblentz evan at snarc.net
Tue Oct 18 23:13:09 EDT 2016

Way back when the old MARCH opened its first exhibit at InfoAge (2005), 
the InfoAge powers that be lent us a collection to curate from an IEEE 
life fellow named Dimitry Grabbe. Among the collection was a board of 
tubes which Mr. Grabbe said was a half-adder module from the ENIAC.

We soon figured out that Grabbe was wrong. The board says Engineering 
Research Associates. ERA had no part in ENIAC. Remington Rand bought ERA 
around the same time as RR also bought Eckert-Mauchly Computer Company. 
ERA + EMCC jointly became the UNIVAC division of Remington Rand.

Thus my working theory has been that the part is from an early-model 
UNIVAC, although there was a slight chance it was an ENIAC replacement part.

ERA was in Minnesota. Their alumni group has been nice to us. Two of 
their members spoke at VCF East 7.0, they gave us some artifacts (most 
notably a UNIVAC 1 technical manual), and there are links to us at 

Tonight I stumbled onto this link:

Go to page 4 of the PDF (page 2 of the document) -- look at the picture 
on the shelves on the right -- it's a plugboard of tubes from a UNIVAC 
1103, circa 1955.

That is EXACTLY the part we have from Grabbe!

They describe it as the "basic logic element". I don't know where Grabbe 
got "half adder" but, as experienced/smart as he was, I trust the guys 
who built the computer.

It's already in our new display case and soon there will be an accurate 
sign with it. :)

Here's a picture of an 1103 in full glory:

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