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Vintage analog computer in surplus auction at University of Texas

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    Vintage analog computer in surplus auction at University of Texas

    There is an interesting analog computer for sale in the current auction at the University of Texas in Austin. EAI model TR-20. The auction uses online bidding which ends on Friday Sept 20 for this item. The current bid price of $35 might be just for salvage value for the materials.



    Searching the internet leads me to think that this computer might be from the 1960s or 70s. These computers where programmed with jumper cables and knobs. I understand that these computers were used to solve complex mathematical problems with analog electrical signals and that the output could be recorded on paper with an analog plotter.


    This EAI TR-20 unit was delivered to my house earlier this week. It had been sitting in Austin for over a year I believe while seller waited for me to figure out how to get it shipped here without too much additional cost. It came with a bunch of patch cables, two function cards, and original power cable tucked inside the drawers.
    More fun.


      Wow! That brought back some memories. I used an Analog Computer in college in the late 60's as part of a lab associated with a Feedback Control System class. As I recall it was hooked up to a huge plotter. I hope you can get it all working without to much trouble.


        Which modules does it have? How many multiply modules? Also does it have any of the diode waveform modules?


          Very cool. We had one of those in the EE dept. at University of Vermont in 1970. I still have 'Basic Analog Computation' by Gerald Peterson, which was our course textbook. Brings back memories.


            It seems to be fairly loaded.

            3 quarter square mult 7.045
            3 dual repetitive integrators 12.1115
            1 tie point network 12.267
            1 variable diode function generator group(16.308 vdfg readout, 2 vdfg modules in the trays underneath)
            1 display network 12.987
            1 relay comparator 6.143
            1 dual function switch group (function switch assembly, readout 12.264)
            1 attenuator group 2.128 (attenuator panel, readout 12.265)

            repeat operation expansion group (repeat operation timing unit 36.082, high speed control panel 20.532)

            10 dual dc amps 6.712
            10 dual attenuator 42.187

            10.179 power supply
            43.037 reference regulator
            6.282 dual dc amp