PSA: That weird hum in a 20 year old Otis controller took me 3 days to trace.

It was a bad capacitor on the logic board, but the sound was echoing through the shaft. Boss said 'just find it' and I spent hours up there with a stethoscope. Anyone know a faster way to isolate board noise from structural vibration?

3 comments

3 Comments

anderson.gavin2mo ago

Ever try a mechanic's stethoscope with the probe removed? Honestly, that cheap trick saved me once. You just use the hose as a long ear, moving it around the board while it's humming. The sound gets way louder right at the bad cap. Way faster than chasing echoes through the frame.

the_abby2mo ago

But what if the board's too loud already and you can't hear the difference?

joel_young29d ago

Reminds me of the time I thought my dryer was haunted, turned out to be a loose penny.