TM 10-3930-669-20 26.  ELECTRICAL SYSTEM DOES NOT MAINTAIN A CHARGE (CONT). KNOWN INFO Engine operates. Batteries OK. Alternator OK. Alternator power wire OK. Wire 34 OK. Relay R1 ground wire OK. POSSIBLE PROBLEMS Relay R1 faulty. Regulator faulty. KNOWN INFO Engine operates. Batteries OK. Alternator OK. Alternator power wire OK. Wire 34 OK. Relay R1 ground wire OK. Relay R1 OK. Regulator OK. POSSIBLE PROBLEMS TEST OPTIONS Voltage test. STE/ICE-R #89. REASON FOR QUESTION If 22 to 24 vdc are not present, relay R1 is faulty.  If relay R1 is OK, regulator is faulty. TEST OPTIONS Verify repair. REASON FOR QUESTION If electrical system maintains a charge, fault has been corrected. 2-288