F&9 = open shunt field fuse

also could be faulty wire connections, open shunt field, shorted T351 transistor, or logics defect.

the flow chart mentions the driver board, this could also be the cause.

check connections:
check field shunt fuse, replace if open

check continuity of wire #34 from line contactor to logics P12-4, wire #71.
7 to 10 ohms? check driver board, no continuity? repair wires or connections

check driver board (field shunt components only)
not failed? replace logics
failed? replace driver board.