Have several GAL IV controllers giving intermittent DON IO failed off fault. This is a hospital complex and today two people were trapped. I have replaced MC, ME & the U31 chip. According to GAL tech support all that is left to cause issue is the Quattro drive board which has the RLY1 & RLY2 on the board and costs $4500. Just wondering if anyone else has come across this and what have you done to fix it?
See attached photo.

Does this happen after a relevel or clipped door lock? Can you duplicate it? I had an issue that the drive wasn't turning on after a abnormal stop. It ended up being a software issue that couldn't be figured out but the fix we did was changing configuration of drive. It was an output that we ended up configuring differently.

Worth checking the forced action relays on the main board as they self check every time the elevator stops. Had similar issue the other day and it ended up being the GTS1 and GTS2 relays.