What was found
WHEN STANDBY PWR SWITCH SELECTED TO OFF POSITION THE CONFIG WARNING SOUNDS AND THE MASTER WARNING LT ILLUMINATES. WHEN STBY PWR BUS DEPOWERED OR WEU B CB P11 B18 PULLED MASTER WARNING LTS ILLUMINATE AND AURAL WARNING SOUNDS. TRIED SWAPPING WEU A AND B PER MM, NO HELP. REPLACED M618 PER SAME REF AND NO HELP. REFITTED ORIGINAL. NO EICAS WARNING MSG IS PRESENT WHEN AURAL WARNING AND LTS ILLUMINATED, REQUIRES FURTHER TROUBLESHOOTING. T-S TO CARD M620 TO CONFIG WARNING MODULE IN P51. REPLACED CARD PER MM31-51-04. ALL INDICATIONS & OPS NORMAL. NO AURAL WARNING WHEN STBY PWR SWITCHED OFF. CARD IS AA 7 DAY NON-POOL LOAN. PAPERWORK IN LOG. CONTAINER IN LOB.