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LGP-30 boards

Bruce Tomlin

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Jan 5, 2010
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536
Location
San Antonio, TX
I found these at a thrift store bin a few years ago and grabbed them because they looked like computer modules. I came across them again today and decided to look up the part numbers. One of them had a match that indicated they were boards from an LGP-30 minicomputer! This is the model that is famous for Mel's blackjack program.

CLOCK GEN 309669
MATRIX DRIVER 309673-A
 

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This is the model that is famous for Mel's blackjack program.

Mel's blackjack program ran on the transistorised RPC 4000 successor machine, but the LGP-30 boasts some other famous users and discoveries. For example, it was the system where Edward Norton Lorenz kicked off investigations into chaos theory, hiring an early-career Margaret Hamilton for help in the effort.

As for me, I'd love to have a charity shop nearby that sold random computer circuit boards from the 1950s...
 
These weren't on a shelf with a price tag, they were in the bins of a by-the-pound Goodwill "salvage" store. It's a sort of "last chance", for stuff that didn't sell, or that they didn't want to bother to try to sell. Stuff is only there for a few hours at a time before they wheel the bins back to load them with new stuff. I've found more than a few wonderful things by just being there at the right time.
 
I found these at a thrift store bin a few years ago and grabbed them because they looked like computer modules. I came across them again today and decided to look up the part numbers. One of them had a match that indicated they were boards from an LGP-30 minicomputer! This is the model that is famous for Mel's blackjack program.

CLOCK GEN 309669
MATRIX DRIVER 309673-A
I actually restored an LGP-30 in 1980 or so, out of parts of two of them. It still had memory contents in the drum. Unfortunately, after I left some idiot (best left nameless) scrapped all the machines I'd restored, including the LGP-30, a CDC 160A (with optional math unit), a PDP-8/S (no great loss) and a one-of-a-kind "Naval Ordnance Ballistic Calculator" which was a giant analog computer comprising 8 or so racks, all in black crinkle-finish paint.
 
These weren't on a shelf with a price tag, they were in the bins of a by-the-pound Goodwill "salvage" store. It's a sort of "last chance", for stuff that didn't sell, or that they didn't want to bother to try to sell. Stuff is only there for a few hours at a time before they wheel the bins back to load them with new stuff. I've found more than a few wonderful things by just being there at the right time.
Mendelson's in Dayton used to have closed-off floors full of stuff (including parts of old computers) that they'd let you wander through if you were a regular and asked nicely. Just bring gloves (sharp edges!) and a flashlight (don't count on the lighting). Unfortunately, in later years they started jacking up prices for most stuff and declared those floors off-limits.

There used to be (mid-1970's) a scrapyard in the Wayne/Paterson (NJ) area that got stuff from lots of the local electronics companies. Kearfott junked all their stuff there, for example.
 
The difference between a Goodwill salvage bins store and a scrapyard is the difference between a firehose and a neutrino detector. With sharks lining up when they turn on the fire hose.
 
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