| Products > Test Equipment |
| 3.5kV power supply teardown |
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| LaurenceW:
Hello Rolycat, I have just scored one of these power supplies on Fleabay. I am looking to use it as a general purpose HT voltage supply. I can see that I am going to have to <ahem> modify one of the safety features - namely its ability to detect ground currents and shut down. Did you ever get hold of a schematic for this or any similar designed units? |
| tom66:
How does it sense output voltage and load current? |
| rolycat:
--- Quote from: LaurenceW on May 28, 2014, 07:39:04 pm ---Hello Rolycat, I have just scored one of these power supplies on Fleabay. I am looking to use it as a general purpose HT voltage supply. I can see that I am going to have to <ahem> modify one of the safety features - namely its ability to detect ground currents and shut down. Did you ever get hold of a schematic for this or any similar designed units? --- End quote --- Afraid not - and it was permanently shut down for a few months because the IEC inlet/filter exploded and chucked its guts all over the PCB: Of course, the unit was switched off at the time, so when I went into my lab to be greeted with a nasty stench it took a while to figure out what had caused it. You may want to keep yours unplugged or switched off at the wall when not in use. I have recently installed a replacement inlet/filter, and it's running again. Very handy bit of kit when you need some serious volts, but as you say the circuit is very safety-conscious. |
| tautech:
That's never a pleasant sight. :scared: Being a switchmode supply, you would be wise to check the E-caps for signs of degradation. Or maybe it was just a case of the mains input filter doing its job? :phew: |
| ve7xen:
I believe Schaffner inlet filters from the 90s have a history of doing this, it plagues test equipment too. If you replace it, don't use NOS, is the general advice. Thanks for the interesting teardown. Surprising that the board doesn't like *all that* different from a low voltage one, was expecting more obvious attention to isolation (though I'm sure it's well designed it just doesn't show). Dave did a teardown of another electrophoresis supply a while ago, if you haven't seen it: |
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