What was found
DURING TAKEOFF, LANDING GEAR WOULD NOT RETRACT. LOST AUTO-THROTTLES, SPEEDS, FLIGHT DIRECTOR, AUTO PILOT. F/O RETRACTED GEAR USING LOCK OVERRIDE.MADE DECISION TO RETURN.ALSO LOST CABIN ALT,TAT PROBE,TRANSPONDER WOULD NOT INDENTIFY TO ATC.EICAS MESSAGES"CABIN ALT AUTO 2,WARN ELEX,NOSE A/G DISAGREE,AIR/GND DISAGREE,TAT PROBE,NO AUTOBRAKES,NO SPEED BRAKES. CHECK FOUND THE STATUS MSG:CAPT PITOT HEAT,L AUX PITOT HEAT ,AIR/GND DISAGREE, NOSE A/G DISAGREE,CABIN ALT AUTO 2,RESET POWER OF THE A/C, ONLY STATUS MSG:AIR/GND DISAGREE,NOSE A/G DISAGREE.ALSO PERFORMED BITE OF PSEU, NO FAULT CODE FOUND. T/S CHECK FOUND THE NOSE GEAR COMPRESSED PROX SENSOR (S10068) BROKEN. SENSOR REPLACED. DURING SWING CHECK, THE LH MAIN GEAR TRUCK COULD NOT BE HOLD POSITION. FURTHER T/S FOUND THE LEFT TRUCK POSITIONER SHUTTLE VALVE HYD FUSE LOCKED & RESET THE HYD FUSE PER AMM 32-32-19-2.ALSO FOUND THE POSITIONER PX TUBE BROKEN, REPLACED THE BROKEN HOSE WITH A TEMPORARY FLEX HOSE PER AMM 20-10-10- 8,CHECKED NO LEAKAGE. PERFORMED TEST OF MAIN GEAR EXTENSION AND RETRACTION PER AMM 32-32-00-5,TEST PASSED.A/C OK FOR SERVICE.