What was found
AUTO-THROTTLE DISCONNECTED DURING DESCENT WHILE IN "VNAV" "PATH" WITH "ARM" ANNUNCIATED AND IN "LVL CHG" WITH "ARM" ANNUNCIATED. GROUNDED - YES. AUTOTHROTTLE BITE PER FIM 22-31 TASK 801 SHOWED SEVERAL INSTANCES OF FAULT 22-31518 "ASM-1 MOTOR PWR" LOGGED FOR LAST SEVERAL LEGS. COMPLETED WIRING CHECKS PER TSR702758 - NO DEFECTS NOTED. DUE TO HISTORY, WITH PREVIOUS REPLACEMENT OF ASM-1 AND FCC-A, REMOVED, REPLACED, AND TESTED AUTOTHROTTLE ASM-2 PER AMM 22-31-91-020-801/AMM 22-31-91-400-801 - ALL TESTS PASS. PERFORMED AUTOTHROTTLE OPERATIONAL TEST PER AMM 22-31-00-710-801 AND AUTOTHROTTLE SYSTEM TEST PER AMM 22-31-00-710-802 - ALL TESTS PASS.