Otis lrs

Have a lift that momentarily doesn't accept calls and sits with doors open. Everytime we show up car is running. Customer isn't resetting. Changed main i/o board, and tone generator. Happens on all floors. Anyone ever seen this?

Could be the door open limit not making. Or door close limit not breaking.

This would cause my calls not to latch?

Is the car stuck at a floor with a hall call lit? I would try the cop power supply and hall button interface board.

Have you checked the photoeyes/door edge sensor? How about the door open button? Those Otis buttons are junk. The randomness leads me to think it could be one of these.

Check or replace the power supply in the COP. You may have ripple on the DC outputs. There are 2 Caps on the power supply. They do decay. The caps are a voltage 2X circuit to supply the 30vdc. If the Caps are bad or decayed, when the line voltage drops the DC reacts violently. At least try replacing the Caps.