What was found
APU SURGING, GROUND MECH SAID APU MADE BOOM SOUNDS. OIL PRESSURE LOOKED GOOD, DUCT PRESSURE VARIED AS APU WOUND DOWN & SPOOLED BACK UP. APU EGT DECREASED AND INCREASED. PERFORMED FIM TASK 49-55, TASK 808 MULTIPLE SURGE CONDITION DURING MES OPS . IAW TECH SERVICES NO BLOCKAGE FOUND. FOUND ELECTRICAL CONNECTOR ON DATA MEMORY MODULE LOOSE INSPECTED AND SECURED CONNECTOR. IAW FIM 49-55-TASK 808 STARTED NR 2 ENG SEVERAL TIMES NO SURGE OF APU OR ABNORMAL APU INDICATIONS NOTED FOUND TO BE AN INTERMITTENT FAULT IAW FIM TASK 49-55-808. TSR ISSUED. REPLACED APU IGV ACTUATOR IAW MM 49-52-12-000-801. OPS/LEAK CHECK OK. PERFORMED IGV ACTUATOR OPERATION TEST. IGVS OPERATE SMOOTHLY. NO INDICATION OF SURGING DURING OPS CHECKS NOTED.