J.  Remove electrical power if no longer required.
Nov 15/78 33-21-71 Page 201
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Window Lights Installation  527 
33-21-71  Figure 201  Nov 15/71 
Page 202 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

3.  Replace Window Light Assembly
A.  Open WINDOW LIGHT circuit breaker on P18 load control center. Attach do-not-operate identifiers. 
WARNING:  HIGH VOLTAGE (200V AC) IS USED FOR WINDOW LIGHT OPERATION. FAILURE TO DISABLE CIRCUIT MAY CAUSE INJURY.
B.  Loosen two screws and pull light assembly from sidewall panel.
C.  Disconnect electrical connector and remove light assembly.
D.  Connect electrical connector and install replacement light assembly.
E.  Install light assembly and secure two captive fasteners.
F.  Close WINDOW LIGHT circuit breaker on P18 load control center. Remove do-not-operate identifiers.
G.  Test Window Light Assembly
(1)  
Provide electrical power.

(2)  
Set WINDOW light switch on attendant's panel to ON. Check that replaced light assembly is operative. 

(3)  
Set switch to OFF.

(4)  
Remove electrical power if no longer required.

527 
May 15/72  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  33-21-71 Page 203 

WINDOW LIGHT BALLAST - REMOVAL/INSTALLATION
EFFECTIVITY
Wide-Body Look and Carry-All Compartment Interior
1.  General
A.  Window light ballasts are located outboard of PSU's (mounted to fuselage frames). Access to ballasts is by lowering PSU's. Most ballasts control two window light fluorescent lamps; however, single lamp ballasts may be installed on end-locations where a second window light is not available.
B.  The ballasts have pigtail wires (do not have terminals) which are connected to the electrical connectors for the lamps and an electrical connector (when installed) to the airplane wire bundle. It is recommended that ballasts be wired to electrical connectors and the assembly (ballasts, wiring, and connectors) be replaced as a unit.
C.  The three ac ground wires, one for each light assembly and one for the ballast, are connected to a common grounding stud. The ground stud is fastened to the airplane structure behind the insulation blankets. These wires may be cut and spliced to facilitate removal and installation of ballast assembly with wiring attached (Detail A, Fig. 401).
2.  Remove Ballast
A.  Open WINDOW LIGHT circuit breaker on P18 load control center panel. Attach do-not-operate identifier.
WARNING:  HIGH VOLTAGE (200 VOLTS AC) IS USED FOR WINDOW LIGHT CIRCUIT. FAILURE TO DISABLE MAY CAUSE INJURY.
B.  Loosen two captive fasteners on each window light controlled by ballast and pull lights from mounting.
Nov 15/78 33-21-81 Page 401
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

C.  Disconnect electrical connectors and remove window light assemblies. Tie strings to
connectors to facilitate installation of replacement (Fig. 401).

D.  Insert small rod or similar device into hole near each inboard corner of PSU and push to release latch (use care not to mar PSU surface), and lower PSU until lanyard is taut.
CAUTION:  DO NOT LOWER PSU BEYOND VERTICAL POSITION. IF OPENED OUTBOARD BEYOND VERTICAL, UNIT MAY BE DAMAGED.
E.  Disconnect electrical connector to ships wire bundle and free wire to ballast.
F.  Disconnect three wires from ac ground stud and free wires from airplane wiring if required.
NOTE:  Wires may be cut to facilitate removal. When cutting wires, provide sufficient length for splicing on installation per airline standard practices.
G.  Remove two mounting screws from ballast (opposite end held by clips).
H.  Pull ballast and wiring to lights from installation. Remove strings from connectors.
3.  Install Ballast
A.  Install ballast by placing one end in mounting clips, connecting bonding jumper and securing two mounting screws.
B.  Using strings, guide window light electrical connectors to window light openings.
C.  Remove strings and connect window lights to electrical connectors.
D.  Install window lights and secure quick-release fasteners (two per light).
E.  Connect electrical connector to airplane wire bundle.
F.  Connect three ground wires to ground terminal.
NOTE:  If wires to ground terminal were cut, splice wires on installation in accordance with standard airline practices.
　
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