What was found
APU ON LINE, SUPPLYING POWER, APU DROPPED OFF LINE NO ELECTRICAL POWER, FAULT LIGHT ILLUMINATED. ACFT GROUNDED. INTERROGATED FMC AND FOUND APU FAULT CODE 49-94299 STARTER GENERATOR OIL FILTER CLOGGED". ACFT CHECKED AND RELEASED IAW MEL 49-1B, APU INOPERATIVE, NO DEFECTS NOTED ON TAIL CONE. ACCOMPLISHED FIM TASK 49-90, TASK 809, STEPS 1 THRU 4, NO CONTAMINATION FOUND IN MAGNETIC DRAIN PLUG. R & R OIL FILTER REF AMM 49-91-12 NO CONTAMINATION FOUND IN USED FILTER. FOUND BAD FILTER BYPASS SWITCH, R & R FILTER BYPASS SWITCH REF AMM 49-91-13, CDU BITE CHECK LOGS NO CURRENT FAULTS. LEAK CHECK ON FILTER, DRAIN PLUG, AND BYPASS SWITCH GOOD. THIS CLEAR MEL 49-IB.