What was found
RELAY 339A1K6 (AUX AC POWER) HAD A LOOSE C1 TERMINAL POST THAT RESULTED IN THE LOSS OF THE C-PHASE DURING EXTERNAL AC POWER OPERATION. SYMPTOMS WERE LOW TRU OUTPUT VOLTAGE AND POOR BATTERY CHARGING. WHEN REMOVING THE RELAY, TEMRINAL POST B1 SEPARATED FROM THE RELAY. FAILED RELAY, HARTMAN P/N DH-31DA HAD BEEN PREVIOUSLY REPLACED FOR LOOSE TERMINALS THAT CAUSED APU POWER PROBLEMS. A DIRECT REPLACEMENT OF THE HARTMAN RELAY IS LEACH P/N ZC-B3N-018. THE -018 LEACH RELAY HAS IMPROVED CONTACT RETENTION TO PREVENT SEPARATION. THE LEACH RELAY WAS THE -018 P/N AND IS ALSO APPROVED FOR INSTALLATION IN THE POWER DIST BOX AS K1 (LAC2) AND K2 (RAC2) MAKING IT THE PREFERRED PART FOR SPARE STOCK.