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TIL a bad capacitor can test fine with a multimeter
Spent 3 hours chasing a no-start on a Whirlpool dryer yesterday, swapped the board, and it still didn't work, only to find a bulging cap on the new board that showed correct capacitance on my meter.
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caseywalker16d ago
Yeah but a multimeter can still catch a bad cap if you check ESR instead of just capacitance. The problem is most cheap meters only test capacitance at a low voltage so they miss internal resistance issues. An ESR meter or a component tester is way better for catching those borderline caps.
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charlesschmidt16d ago
Picked up a cheap ESR meter off Amazon for like 30 bucks and it's caught caps that my Fluke just showed as fine on capacitance. Had a monitor with a bulging cap that still read within spec on capacitance but ESR was way off the chart. That little tool has saved me hours of swapping random caps on old power supplies.
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jackson.max16d ago
Had a buddy who spent three weekends chasing a glitchy power supply in an old arcade cabinet. He tested every cap with his multimeter and they all checked out, so he was about to replace the whole board. Finally borrowed an ESR meter and found three caps with sky high internal resistance. That thing paid for itself in one afternoon.
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