Blew a controller board twice before I caught the real issue

I kept burning out door controller boards on an old Otis in a building near downtown Denver. After the second one I stopped and traced every wire back to the machine room. Turned out a ground wire had a tiny crack inside the insulation that only showed up under load. Put in a fresh ground and its been running smooth for 3 weeks now. Anybody ever find a hidden wire issue that drove them nuts like that?

2 comments

2 Comments

webb.christopher26d ago

Oh man, that ground wire crack story hit close to home. I had something similar on a landing door lock circuit in an old Montgomery down in the Springs. Kept getting intermittent faults, swapped the door controller and the lock itself before I realized the wire in the conduit had a spot where the insulation got chewed up by a bracket. Only shorted out when the car went past a certain floor and the vibration was just right. Drove me nuts for three weeks, almost a month. Ended up pulling a whole new home run because I didn't trust any of the old wire in that run after that. Feels so good to finally track it down though, right?

anderson.spencer26d ago

A month is rough. But that feeling when you find it...