24-29-02
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A
747-400 MAINTENANCE MANUAL
SEE A
SEE  B 
MAIN POWER DISTRIBUTION PANEL, P6 
APU STANDBY 
POWER TRANSFER  A 
RELAY, R7853 

B
APU Standby Power Transfer Relay Installation Figure 401
K06451
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A
747-400
MAINTENANCE MANUAL

 S 024-008
 (7)  Remove the relay from the panel.
 TASK 24-29-02-404-009
 3.  APU Standby Bus Transfer Relay Installation (Fig. 401)
___________________________________________
 A.  References
 (1)  
AMM 24-22-00/201, Manual Control

 (2)  
AIPC 24-33-01, Fig. 61

 (3)  
WDM 24-33-21

 (4)  
SSM 24-33-02

 B.  
Access

 (1)  
Location Zone
 222 Control Cabin, RH

 (2)  
Access Panel
 P6, Main Power Distribution Panel

 C.  
Install the Standby Power Transfer Relay

 S 424-010
 (1)  
Install the relay.

 (a)  
Put the relay in the socket position in the P6 panel.

 (b)  
Install the three screws that attach the relay to the socket in the P6 panel.

 (c)  
Tighten the screws.

 S 414-012
 (2)  
Close the access doors for the P6 panel.

 S 864-013

 (3)  
Remove the DO-NOT-OPERATE tags from the STANDBY POWER switch and the BATTERY switch.

 D.  
Do a Test of the APU Standby Bus Transfer Relay

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

 S 714-015

 (2)  
Do a test of the relay:

 (a)  
Open these circuit breakers:

 1)  P6, Main Power Distribution Panel a) 6K2, MN BAT-CONT INVERTER PWR b) 6K5, TRU-CONT INVERTER PWR

 (b)
Make sure the main EICAS screen operates correctly.

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747-400 MAINTENANCE MANUAL
 (c)
Set the STANDBY POWER switch to OFF.

 (d)
Make sure the main EICAS screen does not operate.

 (e)
Close these circuit breakers:

 1)  P6, Main Power Distribution Panel
 a) 6K2, MN BAT-CONT INVERTER PWR
 b) 6K5, TRU-CONT INVERTER PWR

 S 864-016
 (3) Remove electrical power, if it is not necessary (AMM 24-22-00/201)
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747-400 MAINTENANCE MANUAL
 STANDBY POWER TRANSFER RELAY - REMOVAL INSTALLATION
___________________________________________________
 1.  General_______
 A.  This procedure has two tasks. One task is the removal of the standby power transfer relay (R7227). The other task is the installation of the relay.
 B.  The installation task includes an operational test of the relay.
 C.  The relay is installed in the P6 (main power distribution) panel. The P6 panel is on the right side of the flight compartment.
 TASK 24-29-03-004-001
 2.  Standby Power Transfer Relay Removal (Fig. 401)____________________________________
 A.  References
 (1)  
　
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