Transporting an LGP-30

Jon Elson elson at
Sun Dec 25 16:20:06 CST 2016

>>>> On 12/23/2016 08:06 AM, Cory Heisterkamp wrote:
>>>>> Hi Folks,
>>>>> I recently became the owner of an LGP-30, supposedly in 'working'
>>>>> condition.
I worked just a little bit on a Bendix G-15, a machine from 
about the same vintage.  300 vacuum tubes, about 3000 
silicon (I think) diodes, and a drum.  Really, there are so 
MANY parts in a machine of that vintage that would be really 
tough to get, it could be an incredible project to get it 
running.  The G-15 had an IBM executive typewriter modded as 
the console, with a box of about 50 telephone relays as the 
decode/encode matrix, driven by thyratron tubes.  Our drum 
came pre-scored, I think 3 tracks were grooved down to the 
brass layer.  They had REALLY poor sealing of the drum.  
Part of it was very good, but several large wire bundles 
came in through a drawn aluminum cover with caterpillar 
grommets.  So, no attempt to seal the drum at all, therefore 
lots of dirt got in and packed under the fixed heads.  
Hopefully your LGP-30 has a better arrangement there.

But, lots of connectors, tube sockets, and similar parts may 
be hard to get, not to mention the number of marginal tubes 
that you might need to replace.

I know on the Bendix G-15 the logic was really convoluted, 
to save tubes.  So, they chained several layers of and and 
or gates together before an amplifying tube, to do as much 
logic as possible with each tube.

Then, of course, you'd need to resurrect some bit of 
software to do anything meaningful.  Wow, sounds like a big 


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