Otis MCS 120 entrapment issue

Hi Guys.

Any pointers on this problem? Lift intermittently traps occupants in the car. Then will run ok for a few days after a reset. Thought the problem was that the doors wouldn't actually open on command as found a charred door brake pcb in the door motor assembly. Replaced that along with the DO/DC contactors (poor contact resistance). Still the same issue with entrapments, though the doors now return properly after interrupting the safety beams during the closing phase. Previously, the doors were slow and juddering. Then i replaced the LVC and LV1 contactors, as they were also giving intermittent continuity across the contacts when manually toggled. (LV2 replaced last year). Anyone got an opinion on the Magnetic sensors on the car? and if so, what is the most likely culprit. I can access an Otis tool from a colleague, what should I look out for reported back?

Thanks in advance of your input
Nobbyrobby.

What kind of door machine do you have? Mechanical Otis 9550? Or a another model?
Where in the shaft does the lift stop, when it traps people? Close to the door zone?

Get the error log out of the control board and post the faults here...(LCB-II PCB M1-2-1 Error log)

/Alex

Hi Nobby

Would not think it would be proxi/magnetic switch related as unless the reset involves a synchronisation run the switch state would not change, I know it sounds simple and you have probably checked but if its happening at one floor? you haven't got a flat spot on your lock rollers? when it hits this spot doesn't disengage lock enough to release? otherwise like alex75 what door gear and where is it entrapping passengers I took it as at floor level?