I have an Otis 411 with a Magnetek DSD 412 drive. when the elevator begins to run. M and ME pick but BP doesn't pick to make the brake coil circuit. Drive sends voltage to the armature but the brake doesn't pick. It appears that the BP-OUT gate on the drive terminal is not closing the circuit to pick BP coil. I believe that the mother board sends a serial link communication to the drive to make the circuit. all safety and door locks circuits are made. drive runs for about 5 seconds and then gives up. Has anybody ever had this problem.