Faulty DZ relay on the main CPU board. One side of the contacts would hang up intermitting. Thanks guys.
Ah right, thought it would be a fault in this area. Just for your info, a lot of times, particularly when doing upgrades of circuits like door operators, you haven't enough contacts required for the job. Sometimes its current size, not enough contacts etc. So what you do is either parallel up another relay or use an existing contact to drive another relay then in turn redirect the wiring to this new relay. This is probably why you have 2 DO/DC relays.
