1) Insert a torque wrench in the manual drive of the hook
actuator. 2) Turn the torque wrench slowly in the CLOSE direction. 3) Make sure you can turn the torque wrench 4 to 6 turns
before the actuator hits the internal stops.
NOTE: The actuator hits the internal stops when the
____ torque increases 15 to 20 pound-inches during one-half turn of the wrench.
4) If internal stop is not contacted in 4 to 6 turns, adjust the switch as follows: a) Subtract the actual number of turns remaining from the
5 turns required. b) Add this number to 9 turns. c) Set the hook close switch to operate at this point.
EXAMPLE: Assume 1 turn remains until the stop is contacted. The 5 required turns minus the 1 actual turn equals 4 turns. Add this to 9 turns to get 13 turns. Turn the hook actuator 13 turns toward the open position. Set the hook closed switch to operate at this point.
EXAMPLE: Assume 7 turns remain until stop is contacted. The 5 required turns minus the 7 actual turns equals -2 turns. Add this to 9 turns to get 7 turns. Turn the hook actuator 7 turns toward the open position. Set the hook closed switch to operate at this point.
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747-400 MAINTENANCE MANUAL
d) Put lockwire on the locknuts when the switch is adjusted correctly.Adjust the midspan latch open switches as follows (Fig. 517):
NOTE: You can use this procedure for the two midspan
____ latch open switches. To prevent unnecessary steps, do each step for both switches before you start the subsequent step.
1) With the door closed, loosen the locknuts and adjust the switch in the bracket to get the initial adjustment (Section A-A).
CAUTION:_______ IN CASE THE DOOR DOES NOT OPEN, STOP IMMEDIATELY. DO
NOT OPERATE THE DOOR CONTROL SWITCH. HOLDING THE
DOOR CONTROL SWITCH MAY DAMAGE THE ACTUATOR. WAIT AT
LEAST 1 MINUTE BEFORE SECOND ATTEMPT. IF THE DOOR
STILL DOES NOT OPEN, WAIT AT LEAST 10 MINUTES BEFORE
THIRD ATTEMPT.
2) Open the door approximately 1 to 2 feet.
3) Set latch actuator in external stops open position (Fig. 510) as follows: a) Use a torque wrench with a dial indicator to manually
turn the actuator counterclockwise at 25 |5 pound inches. b) Find the point at which the manual torque increases by 15-20 pound-inches. c) Turn the manual drive 1/2 turn clockwise.
NOTE: This is when the external stops are touched.
____
d) Make sure the plungers for the midspan latch open
switch are not fully pushed in.
4) Turn the latch actuator 30 turns clockwise.
5) Make sure the striker plate does not touch the switch
plunger.
6) Disconnect electrical connector DX225C from the cargo door junction box.
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747-400 MAINTENANCE MANUAL
7) As you turn the latch actuator 8 |1/4 turns counterclockwise (switch actuates 22 |1/2 turns prior to external stops [open] position [Fig. 502]), adjust the switch to get a continuity between pins 7 and 8 (aft midspan latch switch) or pins 5 and 6 (forward midspan latch switch) of connector DX225C.
NOTE: The switch must operate as the latch actuator is
____ turned to the open stops (counterclockwise). One-half turn of the limit switch locknut will change the switch operation point approximately one turn on the latch actuator.
8) Install the lockwire and locknuts. 9) Connect electrical connector DX225C to the cargo door junction box.
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