I used to think those old relay logic controllers were junk until a call in St. Louis

I was working on a 1970s Otis in a downtown office building last Tuesday. The car kept stopping between floors, and my first thought was to just push for a full controller swap. The building manager, an older guy named Frank, said 'Just check the sequence charts first, kid.' I traced the step-by-step logic and found one worn relay in the leveling circuit. Replacing that $40 part fixed it in an hour. Now I see the value in really knowing that old stuff before calling it scrap. Anyone else have a story about saving an old system?

3 comments

3 Comments

shane17021d ago

Frank was right to make you check the sequence. A lot of guys just see old relays and want to throw a new board at it. The real skill is reading those old ladder diagrams and knowing what each click means. You can keep those old Otis units running for decades with basic parts and some patience.

henry_anderson5421d ago

But is it really that deep?

riverb1321d ago

Can't fix what you don't understand, right?