What was found
AFTER TAKEOFF LANDING GEAR HANDLE WOULD NOT MOVE TO UP POSITION. FOLLOWED QRH GEAR HANDLE REMAINED IN DOWN POSITION. PROBLEM DUPLICATED BY VISUAL CHECK MLG TRIM INTERLOCK CYLINDER, FOUND IT FAILED TO EXTEND AND CAUSED L/G CONTROL LEVEL UNABLE LIFT TO FULLY UP POSITION, WITH HYD SYS PRESSURIZED. PER MM 32-37-01-4, RESET UPSTREAM HYD FUSE NO HELP, BLEED RT TRIM CYLINDER HYD FLUID STILL NO HELP. BLEED LT TRIM CYLINDER, INTERLOCK CYLINDER FUNCTION BACK NORMAL, LANDING GEAR CONTROL LEVEL LIFT UP NORMAL. FOR PRECAUTION, ALSO REMOVED AND REPLACED TRIM CYLINDER FUSE ASSY AS PER MM 32-37-06-4, LEAK CHECK PASSED AND L/G CONTROL LEVEL FUNCTION TEST OK. A/C OK FOR CONTINUE SERVICE.