What was found
WITH NO POWER ON ACFT, BATTERIES DO NOT COME ONLINE, PROBLEM IS INTERMITTENT. WITH EXT POWER ON BATTERIES WORK NORMAL AND SHOW FULL CHARGE, CFDS SHOWS NO FAULTS. INSTALLED NEW BATTERY LINE CONTACTOR IN 6 PB1 AND 6 PB2 POSITION, NO HELP. PROBLEM STILL EXISTS REINSTALLED ORIGINAL UNITS. REPLACED BOTH NR 1 AND NR 2 BATTERY SWITCHES AND SYS CKD OK. REF AWM 24-38-01.