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10 year old elevator controller took me 6 hours to troubleshoot last Tuesday
Found out the main CPU board had a hairline crack that only showed up when the cabinet got warm. Never would've found it without swapping out the whole board just to test. Anyone else run into intermittent faults that only happen under specific temp conditions?
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daniel4743mo ago
Ever had a friend who spent 3 days chasing a ghost fault that only happened when it rained?
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the_jordan4mo ago
Man that sounds brutal. I had a similar thing with a VFD drive in a HVAC unit a few years back. It would run fine for like 2 hours then just drop out. Turns out the power supply cap was going bad but only after it got hot from running. I put a freezer spray can right on the cap while it was acting up and bam the drive came back to life. That's how I narrowed it down. Saved me from swapping a whole board that cost like 800 bucks. Heat related intermittent faults are the worst because you can't always reproduce them in a cold shop.
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theac634mo ago
Freezer spray is the best trick for finding heat related faults. I keep a can in my truck for exactly this reason. Had a compressor contactor that would only act up after running for about an hour. Used the spray on the control relay and it kicked right back in. Saved me from swapping a $300 contactor for a $5 relay. The trick is to be careful not to overspray onto other components though. Too much cold can crack a solder joint if you're not quick about it.
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