What was found
DURING TAXI, CAPTAIN NOTED APU INLET DOOR WOULD NOT CLOSE. CAPTAIN ELECTED TO RETURN TO GATE FOR MAINTENANCE TROUBLE-SHOOTING. AIRCRAFT TAXIED TO GATE WITHOUT FURTHER INCIDENT. MAINTENANCE PERSONNEL TROUBLE-SHOOTING DETERMINED THAT APU INLET DOOR LINKAGE BINDING. DOOR LINKAGE WAS CLEANED AND LUBED. OPS CHECK PERFORMED WITH NO FAULT. AIRCRAFT RETURNED TO SERVICE. (M)