(3)  
AMM 51-24-13/701, Water Displacing Corrosion Preventive Compound

 (4)  
AIPC 24-31-06, Fig. 1

 (5)  
WDM 24-32-31

 (6)  
SSM 24-32-03

 C. Access
 (1)  Location Zone
 271 Passenger Cabin, LH

 D. Install APU Transformer Rectifier Unit
 S 424-010
 (1)  
Position APU TRU onto support frame of the E-33 equipment rack. Align bolt holes.

 S 434-011

 (2)  
Install four bolts with washers that secure APU TRU to the E-33 rack. Tighten bolts.

 S 034-019

 (3)  
Remove three nuts from the APU TRU fan shroud to gain access to the APU TRU power terminals.

 S 434-025
 CAUTION: ENSURE EACH TERMINAL LEAD IS CONNECTED TO PROPER TERMINAL STUD
_______ ON APU TRANSFORMER RECTIFIER UNIT. INCORRECT INSTALLATION WILL RESULT IN CIRCUIT MALFUNCTION AND/OR DAMAGE TO EQUIPMENT.
 MAKE SURE ROUND WASHERS ARE INSTALLED BETWEEN TERMINAL NUT AND POWER LEAD. DO NOT INSTALL ANY WASHERS BENEATH POWER LEADS. THIS WILL RESULT IN LOCALIZED RESISTANCE HEATING WHICH COULD CAUSE BURNING OF TERMINALS.
 (4)  Connect APU TRU power leads to APU TRU terminal block and secure with washers and terminal nuts.
 NOTE: On APU TRU P/N 28VS200Y-4B-1, tighten the terminal nuts to
____ 103-113 pound-inches (11.6-12.8 N.m.). On APU TRU P/N 28VS200Y-4B-2, tighten the terminal nuts to 185-195 pound-inches (20.9-22.0 N.m.).
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A 747-400 MAINTENANCE MANUAL
 (5)  S 424-024If you disconnected the ground wire from the negative post of the TRU to the ground stud, tighten the ground stud nut to 175-210 pound-inches (19.8-23.7 N.m.).
 (6)  S 434-027Reinstall APU TRU fan shroud and secure with three nuts. nuts. Tighten
 (7)  S 434-013Connect electrical connector (DH123) to receptacle on APU TRU.
 (8)  S 764-030Check the APU TRU ground stud. (a) Remove the sidewall insulation blanket fastener (AMM 25-59-05/601). (b) Move the sidewall insulation blanket to gain access to the APU TRU ground stud. (c) Make sure the terminal lug is not damaged, deformed or anealed (AMM 20-30-00).
 NOTE:____ If the terminal lug is damaged, deformed or anealed replace the lug (SWPM 20-30-00).
 CAUTION:_______ DO NOT PULL ON THE GROUND WIRE AFTER THE GROUND STUDS ARE TIGHTENED. DAMAGE TO EQUIPMENT OR AIRPLANE STRUCTURE MAY OCCUR.
 (d) (e) (f)  Make sure each APU TRU ground stud nut is torqued from 180-200 pound-inch (SWPM 20-30-00).Make sure the electrical bonding of the APU TRU ground studs are 0.0001 ohms (SWPM 20-20-00).Clean the fuselage area next to the APU TRU ground studs. Make sure the APU TRU ground stud area is free of dust and dirt (AMM 51-24-13/701).

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A
747-400 MAINTENANCE MANUAL
 CAUTION: ALLOW THE CORROSION INHIBITING COMPOUND SOLVENTS TO
_______ EVAPORATE. INSULATION BLANKETS WHICH TOUCH THE CORROSION INHIBITING COMPOUNDS BEFORE COMPLETE SOLVENT EVAPORATION WILL BE DAMAGED. DAMAGED INSULATION BLANKETS CANNOT BE CLEANED AND MUST BE REPLACED.
 (g)  Apply corrosion inhibiting compounds to the fuselage areas exposed by cleaning (AMM 51-24-13/701).
 NOTE: Corrosion inhibiting compound BMS 3-23 requires 4 hour
____ standing time after application to let the solvents evaporate. Compounds BMS 3-26 and BMS 3-29 require 6 hours standing time after application to the solvents evaporate.
 NOTE: Corrosion inhibiting compound Dinatol AV8, LPS Hardcoat
____ and Zip Chem ZC023 dries tack free in 1 hour. Accelerated drying time of 6 minutes can be obtained when warm air is applied over the area. Warm air is air with a temperature lower than 120 degrees F.
 (h)  Install the insulation blanket and fastener (AMM 25-59-05/601).
 S 864-015
 (9)  
Remove DO-NOT-CLOSE identifiers and close circuit breakers as follows for APU TRU:
　
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