TM 10-3930-669-20 6.  HOUR METER DOES NOT OPERATE (CONT). KNOWN INFO All 24 vdc circuits operate. Wire 5 OK. Hour meter ground wire OK Hour meter OK. POSSIBLE PROBLEMS Wire 64 faulty. Alternator faulty. KNOWN INFO All 24 vdc circuits operate. Wire 5 OK. Hour meter ground wire OK. Hour meter OK. Wire 64 OK. POSSIBLE PROBLEMS Alternator faulty. TEST OPTIONS Continuity test. STE/ICE-R #91. REASON FOR QUESTION If continuity is not present , wire 64 is faulty. TEST OPTIONS Continuity test. STE/CE-R #91. REASON FOR QUESTION If continuity is not present, resistor is faulty.  If resistor is not faulty, pulse tach in alternator is faulty. ¬ ¬ 2-158