This one started in January. Three stop, front only, homes on 2, 1st floor locked out. ROA. Complaint car not opening doors at 3. once I caught it doing it, guess what wrong place wrong time. Checked all power supplies. Seemingly good. But then runs fine. Another call, doors open, car six inches low on 3. But ROA. Reed switches, didn't help. Next call, DOA .Change AC tap on transformer for COP power supply. Although it says 9 VDC on print had 11VDC, now 13VDC. Car runs fine. Next call DOA, Change power supply in COP, Car runs fine. Next call DOA, Change MCB, car runs fine. Next call DOA, jump regulator on RB1 YEAH. Ran for 2 days. NOPE. Change C1 Cap, was 27.6, still 27.6 you got it, NOPE. change DRF1, NOPE. POR, car makes one trip, either up or down, 2 floor or one floor, doors open buzzer goes off, doors close, door open button works, no car or hall calls. It will shut down even when it homes. Next is RB1. Any other thoughts............