via this auctionAs always, the seller's description:
"This machine is a combination of two Comdyna GP-10 analog computers and a MicroHybrid I digital control and interface system. It is one of only 20 made for the US Navy for use in their control laboratory schools. It offers 20 Operational Amplifiers, multipliers, coefficient setting pots, etc etc. The MicroHybrid has comparators, two counters, and I/O facilities for controlling the two GP-10 machines. The Operator's and Maintenance Manual, as well as various descriptive brochures, are included. It is assumed you have a basic familiarity with analog computation techniques, and the proper math backround to be able to set up the programming.I purchased this machine some years ago for use in experimental music synthesis and composing. It was to be an expansion of my Comdyna GP-6 machine (which I am using currently). It was purchased in the condition shown and described below. My music research has branched out into other channels, so this Computer is not going to be used for the original purpose. Time to get it out of storage in into use!
This LGP-20 apparently had it's control panel broken at some point in it's life, and another LGP panel was provided. The replacement panel was cut out of a machine, and has a power transformer and the external sockets, as well as a connector for the regulator board attached. These parts are also on the main machine. The control panel harness must be spliced into the existing wiring. The main machine harness has bits and pieces of the switches, etc still attached. The clean-up and splicing job should take about an hour for a competent tech to perform.
The Power Supply regulator board is missing. There are three main options:1. If one is still available from Comdyna, purchase it. Even a 'blank' board can then be easily populated.
2. Make a new board. All parts are common and are instantly available from Mouser, Digikey, etc,. The complete schematics and layout is in the Manual.
3. Operate the System using external power supplies - plus/minus 15VDC, plus/minus 10VDC (well regulated) and plus 5VDC for the MicroHybrid is required. Current is an amp or two, and there are many supplies which will do the job.
I have recently powered up the MicroHybrid portion of the System and it appears to be working as it should.
If you are experienced in basic electronic-technician level work, or can enlist the services of someone who is, restoring this machine will be easy. I just have too many other projects currently to allow the luxury of time needed for it." This one in via Brian Kehew.
Update via dkelvey in the comments: I have a LGP-20 that is working. I just this last weekend had it doing spyrogrphs at the Maker Fair in San Mateo, CA. I can assist in connecting the wires by giving someone a point to point listing. I'd be most interested in a copy of the LGP-20 manual though. That I don't have. See a quick flash of my machine and output at: http://www.youtube.com/watch?v=bDnIGM-J4Os [comes in at 1:30]
Dwight "
