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

Herb Johnson hjohnson at retrotechnology.info
Wed Oct 19 11:12:21 EDT 2016

This discussion caught my eye and I did some quick Web searching.


at bitsavers.org under "pdf" and "univac" and "1103", has general 
descriptions of Univac 1103 modules, or in their terminology "unit 
chassis". There's a single photo of a chassis, which clearly is of the 
same kind as the module in discussion. I believe it states there are 86 
kinds of unit chassis. This manual is dated Feb 1957 from "Remington 
Rand Univac".

The manual


has on page 1 and many other pages, "Remington Rand / Engineering 
Research Associates Division" Page one adds "(street) St. Paul 
Minnesota". That confirms the "ERA" identification of the VCFed's 
module. This manual has text descriptions of various (vacuum tube) 
circuits, I/O and memory elements. Seems to be a kind of primer on 
computing and logical elements, and on the 1103's programming and I/O 
facilities. It's pretty informative as an introduction to 1103 "technology".

Other bitsavers 1103 documents from 1953 forward identify "ERA 1103" 
versus the "Univac Scientific Model 1103A". But -  no schematics, no 
list of unit chassis numbers were immediately evident in my quick look.

It may be difficult to find a manual for the specific module held by 
VCFed. The image in the PDF from Evan is blurry. A better image may show 
a "unit chassis" part number that can be Google searched to find a 
document with specific information. This is a hint.

Why will a unit-chassis manual be difficult to find? I'm "guessing" that 
most of the Univac manuals were for use on-site to operate the Univac, 
or off-site to learn how to program it. The point of modular 
construction, was to allow on-site persons to run test operations on the 
computer, to identify down to the "unit chassis" any problems. Then the 
unit chassis could be pulled, repaired off-site, and/or replaced on 
site. Military procedures for system repairs may have been different.

lose reading of the "sysMaint" manuals may reference that process and 
would be informative.

Herb Johnson

Herbert R. Johnson,  New Jersey USA
http://www.retrotechnology.com OR .net

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