What was found
APU INOP UPON LANDING MULTIPLE STARTS ATTEMPTED APU FAULT CODE ILLUMINATED. GROUNDED - YES. REMOVED AND REPLACED STARTER CONVERTOR UNIT PER B737-800 AMM 49-41-61-000-801/AMM 49-41-61-400-801. ACCOMP 2 STARTS THEN P91 A11 CIRCUIT BREAKER TRIPPED. REMOVED AND REPLACED STARTER POWER UNIT PER AMM 49-41-71-000-801. PERFORMED START POWER UNIT INSTALL TEST PER SAME. TEST PASSED APU STARTED WITH NO ISSUES. APU BITE SHOWS NO CURRENT FAULTS. PERFORMED LEAK & OPS CHECKS ON APU STARTER GENERATOR PER AMM 49-41-21. FOUND NO DEFECTS. PERFORMED LEAK CHECK ON APU STARTER SCAVENGE FILTER AND LUBE FILTER PER AMM 49-91-12 FOUND NO LEAKS. PERFORMED LEAK CK ON APU DRAIN PLUG PER AMM 49-91-81. FOUND NO LEAK.