Miprom21

What will cause the relay interface board to sit there and just flash the inputs and outputs?

Reseat everything. Check all your power supply connections.

Have you tried isolating the card rack by disconnecting the bus wire? Bad inputs and outputs, or a bad card rack can cause it to flash.

Management has let this unit set idle for weeks and the field people haven't listen to what I have asked them to do. I suggested the above things to look at and try, thank you very much, but was met with confrontation and told it has already been done. I'll make this short. I took the ribbon cables loose, blew them and the MSU and replay pilot connectors with compressed air. Three weeks this unit has been down, I spent 15 minutes on it. Unit works and I am looking at retirement after almost 40 years in this business.

Well quit looking and go… apprehend it!
Congratulations!

Thank you for the update.