Peak,
Did you try Fire Recall Phase 1? Did the doors open? Both key switches returned to "Off" positions?
Will the unit take and answer car calls?
This is a simplex yes? If it's an early TAC50, the PMI boards are laid out similar to a late Dover Traction I believe. On the board that has the fire stuff, check those wire termination header plugs for good wire connection and that the plugs are seated fully, then try to reload the job. Module locations should be on the inside controller door and they are on the print, and prints are job specific.
Bad FE module? (I forget what acronym they give fire stuff, I know it's not FE, (FSM?) but whatever main floor recall is).
Sure seems odd that this seemed to "just" happen out of nowhere.