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. NO EICAS WARNING MSG IS PRESENT WHEN AURAL WARNING AND LTS ILLUMINATED, REQUIRES FURTHER TROUBLESHOOTING (PARTIAL). T/S TO CARD M620 TO CONFIG WARNING MODULE IN P51. REPLACED CARD PER MM. 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.