Teardown & Repair of a Stanford Research PS350 5000V, 25W High Voltage Power Supply

In this episode Shahriar repairs a Stanford Research Systems Model PS350 5000V-25W High Voltage Power Supply. The unit continuously displays 2.5kV without the output being enabled and produces no output voltage. Verification of power supply voltages reveals the issue is linked to a disconnected 15V voltage regulator IC. After the repair, the output voltage is verified with both positive and negative outputs. The principle operation of the instrument as well as the Cockroft-Walton high voltage generator is reviewed.


  1. Sandra says:

    I don’t know if you followed my repair log over at eevblog but I did a repair on this unit, enabled GPIB on the PS350 then we went into some reverse engineering of the code (thanks ‘alm’ for his help) and finally (thanks Dexter2 for his help) came up with how to calibrate it including labview code to assist.

    Just wanted to share with you some. really enjoy you’re video’s.
    the eevblog posting is here

  2. RadioMark says:

    I discovered your blog by looking at the review of the top of the line spectrum analyzer from Rigol. Watched a couple of the repairs bringing back memories of back when I used to find this kind of thing to be great fun. Bench work has mostly gone the way of the nickel Coke in my world of broadcast engineering. It’s apparent you enjoy the reverse engineering process. I feel like a genuine geek again following along with your troubleshooting process (and getting a little ahead once in a great while). Thanks for a lost afternoon 😉

  3. Mike says:

    Seems like a lot of fun and education could be had by setting up as a sort of high-voltage curve tracer (albeit only one polarity at a time). With a ramp waveform to the voltage control input and the current monitor and it to the X and Y of a scope, one could look at the I-V curves of all kinds of things. For a start, I think (at least if the ramp was not too fast), one could observe the corona discharge before a spark gap really arcs over. Also there’s the obvious destructive tests of cheap 1n4007 rectifiers, ceramic disc caps, etc — probably want to set up a test fixture with a bit of a plastic shield in case they “pop”. 🙂

  4. Guest says:

    Could you post the firmware you grabbed off the EPROM in your blog? Could be quite interesting…

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