E.
Prepare for Operation
S 495-022
WARNING: DO NOT OPERATE THE DOOR IF ONE OR THE OTHER ACTUATOR SHEAR PINS
_______ ARE BROKEN. YOU MUST REPLACE THEM BEFORE YOU OPEN THE DOOR. IF YOU DO NOT REPLACE THEM, INJURY OR DAMAGE CAN OCCUR.
(1)
Install the safety barrier across the door opening.
S 865-003
(2)
Open these circuit breakers and attach DO-NOT-CLOSE tags:
(a)
On the Nose Cargo Door Power Panel H122: 1) DOOR LIFT
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747-400 MAINTENANCE MANUAL
S 025-004
(3)
Disconnect the flexible drive shafts at the linear actuators.
F.
Lift Mechanism Manual Drive Check
S 865-019
(1) Simultaneously hold the control switch and the power switch until the latches are fully opened and the push-pull cam actuator has completed its stroke.
S 865-006
CAUTION: MAKE SURE TO DRIVE THE TWO LINEAR ACTUATORS SIMULTANEOUSLY.
_______ THE UNEQUAL LOAD DISTRIBUTION CAN CAUSE DAMAGE TO THE LINEAR ACTUATORS.
(2) Simultaneously drive the two linear actuators with the alternate drive extension or the speed wrench in the open direction (counterclockwise) until the door is partially opened to approximately 2 feet.
NOTE: The same air pressure supply and the hose diameter must be
____ used on the alternate drive extension or the speed wrench to make sure the rotational speed (RPM) is the same.
S 715-017
(3)
Make sure the lift mechanism manual drive operates correctly.
S 865-016
(4)
Open these circuit breakers and attach DO-NOT-CLOSE tags:
(a)
On the Auxiliary External 2 Power Center-Right Panel P715: 1) NOSE CARGO DOOR
(b)
On the Power Distribution Center-Right Panel P415: 1) NOSE CARGO DOOR CONT
S 865-009
CAUTION: MAKE SURE TO DRIVE THE TWO LINEAR ACTUATORS SIMULTANEOUSLY.
_______
THE UNEQUAL LOAD DISTRIBUTION CAN CAUSE DAMAGE TO THE
LINEAR ACTUATORS.
(5) Simultaneously drive the two linear actuators with the alternate drive extension or the speed wrench in the closed direction (clockwise) until the push-pull cam touches the cam rollers.
NOTE: The same air pressure supply and hose diameter must be used
____ on the alternate drive extension or the speed wrench to make sure the rotational speeds (RPM) are the same.
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MAINTENANCE MANUAL
S 715-010
(6) Make sure the lift mechanism manual drive operates correctly.
NOTE: After any manual operation of the lift system, it is
____ necessary to adjust the lift system before electrical operation.
S 825-011
(7)
Adjust the door as follows:
(a)
Remove the DO-NOT-CLOSE tags and close these circuit breakers: 1) On the Auxilary External 2 Power Center-Right Panel P715: a) NOSE CARGO DOOR 2) On the Power Distribution Center-Right Panel P415: a) NOSE CARGO DOOR CONT
3) On the Nose Cargo Door Power Panel H122: a) DOOR LIFT
(b)
Make sure the actuator for the push-pull cam is extended and that the cam rollers touch the cam.
(c)
Simultaneously hold the control switch in the open position and the power switch in the on position for 5 to 10 seconds and release them.
NOTE: Door will not move, as the flex cables are disconnected.
____
(d)
Open this circuit breaker and attach the DO-NOT-CLOSE tag:
1) On the Nose Cargo Door Power Panel H122: a) PULL UP CAM
(e)
Simultaneously hold the control switch in the closed position and the power switch in the on position until the drive unit motor stops.
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