off the top of my head, the drive gets a few 30v feeds from a couple of rs3 boards and if the drive has a problem the input to the RS board goes low and the RCB shuts down in DBF mode(drive brake fault). the board you had repaired might not have been repaired right or the RS3 board might be bad, those older RS board are starting to fail but can be easily replaced with a newer RS5. all otis RS boards do the same thing from 1989-present. the SCIO or CUB board could be bad also. im pretty sure there is a couple of hoistway switch inputs the car has to see on a correction run at the first floor. MRQ's have been know to lock faults in ram have you cleared the pf ram? also if the write/protect switch was left in write on the RCB a power bump or failure can change i/o's. MRQ's are a guessing game sometimes, unfortunately some parts are getting hard find.