information about the Bendix G-15 and Rice Research Computer?

Jon Elson elson at
Fri Sep 11 21:38:00 CDT 2015

On 09/11/2015 11:31 AM, Cory Heisterkamp wrote:
> Are there any operational G-15's out there? Seems like this would be a good
> model to restore/demonstrate that doesn't come with all the usual baggage
> of a first gen machine (exotic power, A/C requirements, thousands of tubes,
> etc). -C
Supposedly one in Australia is at least close to operational.

I tried to help get a G-15D running at Washington University 
in about 1972.  it was one of those NASA surplus deals, "you 
pay the shipping and it is yours".  We got the G-15, 
typewriter and typewriter control box and several huge boxes 
of documents and paper tapes.  It wasn't that hard to get 
power run to the machine, we had a lab available that was 
proven to be able to handle the heat load. But, then, it 
didn't seem to work.  I think the relays in the typewriter 
control had dirty contacts, and there were a LOT of relays 
in there!  The thing had 300 tubes of dubious quality.
Finally, I determined that the drum was badly scored, there 
were several tracks that were scored down to the brass.  So, 
obviously, no existing program could be expected to run, 
with several shot drum tracks.

This is one of the major problems with the G-15, there was 
VERY poor protection of the drum from dust.  They had a 
formed aluminum cover, but the cable bundle went through a 
hole with caterpillar grommet around it, so plenty of room 
for dirt to get in.

The diode boards were paper-phenolic, and almost certainly 
would get more brittle as they aged.

But, yes, it was a fairly simple machine, I don't think you 
could strip a tube computer down much further than the G-15 
and still have it do useful work.


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