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The controller had a failure when a contactor failed closed. Power up without a precharge caused smoke and a BIG bang.
I've cut off the legs on 2 of the 20 MOSFETs that had visible damage.
I connected a 20 amp bench power supply to M- and B- and run 20+ amps through for a few minutes. None of the MOSFETs got warm to the touch or changed temperature - used an infra-red thermometer.
I want to sign out a ductor (ohm meter that injects 10 amps, measures micro-ohms) from work this weekend and see if I can use it to determine WHICH MOSFET(s) are still failed closed.
My next attempt (if the Ductor does not work) is to hook up my 110V welder, set for 20 amps (or 30A, or 40A .. it only goes up to 60A) and push some decent current through whichever MOSFETs are still failed closed. I THINK it will work, but I guess I'll try the Ductor first and see if it obvious which FETs are gone and just cut off the legs.
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