D.
Install the Downlock Sensor (Fig. 401)

 S 424-009
 (1)  
Install the downlock sensor:

 (a)  
Twist the sensor wires together.

 (b)  
Attach the line that you kept in the conduit (during the removal) to the sensor wire ends.

 (c)  
Use the line to carefully pull the wire ends through the conduit.

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747-400 MAINTENANCE MANUAL
 (d)  Install the sensor with the mounting screws.
 NOTE: A correctly installed sensor will give the necessary
____ clearance as shown in Fig. 401. Clearance adjustment is usually not necessary. If the target has been moved or damaged, you must do a check of the clearance.
 1)  Before you measure the sensor-target clearance, make sure hydraulic power is removed from the wing gear (hydraulic system no. 4) (AMM 29-11-00/201).
 2)  Measure the clearance between the sensor and the target and compare it to the valve shown on Fig. 401.
 3)  If adjustment is necessary, install new shim(s) or remove the laminations from the shims to get the clearance as shown on Fig. 401.
 (e)  
Cut the sensor wires to the correct length and install the new terminal lugs on the sensor lead ends.

 (f)  
Connect the terminal lugs on the sensor wires to the terminal strip.

 (g)  
Do a check of the terminal positions and the wire color code for the correct electrical connection.

 CAUTION:_______MAKE SURE YOU SEAL THE ELECTRICAL TERMINALS. IF YOU DO NOT SEAL THE TERMINALS, CONTAMINATION CAN GO INTO THE JUNCTION BOXES AND CAUSE DAMAGE TO THE SENSORS.

 (h)  
Seal the electrical terminals: 1) Clean the bare surface of the terminals with the solvent. 2) Apply a thin layer of the primer on the bare surface of the

 terminals and let the primer dry. 3) Apply the sealant on the surface of the terminals with a short bristle brush.

 (i)  
Tighten the conduit nut to the sensor by hand.

 (j)  
Install the lockwire on the conduit nut.

 (k)  
Install the junction box cover.

 S 864-024
 (2)  
Remove the DO-NOT-CLOSE tags and close these circuit breakers on the overhead circuit breaker panel, P7:

 (a)  
7F23, LANDING GEAR DSP & CONT ALTN

 (b)  
7F22, LANDING GEAR DSP & CONT PRI

 (3)  
Put the airplane back to the ground mode (Ref 32-09-02/201).

 S 444-027
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 E. Adjust the Downlock Sensor
 NOTE: A correctly installed sensor will give the necessary clearance as
____ shown in Fig. 401. Clearance adjustment is usually not necessary. If the target has been moved or damaged, you must do a check of the clearance.
 S 824-013
 (1)  
Adjust the downlock sensor:

 (a)  
Make sure the clearance agrees with that shown on Fig. 401.

 (b)  
If adjustment is necessary, install new shim(s) or remove the laminations from the shims to get the clearance as shown on Fig. 401.

 F.
Do a Test of the Downlock Sensor

 S 864-014
 (1)  
Supply electrical power (AMM 24-22-00/201).

 S 714-015

 (2)  
Do the ground test for the PSEU (AMM 32-09-03/501).

 S 864-016

 (3)  
Remove the electrical power if it is not necessary (AMM
 24-22-00/201).

 S 094-017
 WARNING:  REFER TO AMM 32-00-30/201 FOR THE LOCK REMOVAL PROCEDURE. FAST MOVEMENT OF THE DOORS CAN CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (4)  Remove door locks on the main landing gear (AMM 32-00-30/201).
　
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