R  . pin F of the external power receptacle and pin B/12E of the  
R  GAPCU.  
R  (a) If the AC or DC voltage is out of the limits:  
R  - repair or replace as necessary.  
R  (b) If the AC or DC voltage is not out of the limits:  
R  - replace the GAPCU (24XG) (Ref. AMM TASK 24-41-34-000-001) and  
R  (Ref. AMM TASK 24-41-34-400-001).  
R  B. Do this procedure to make sure that the system operates correctly.  
R  (1) Energize the aircraft electrical circuits from the external power  
R  (Ref. AMM TASK 24-41-00-861-002).  
R  (2) De-energize the aircraft electrical circuits from the external power  
R  (Ref. AMM TASK 24-41-00-862-002).
R TASK 24-41-00-810-812
R  Failure of the External Power  
R  1. Possible Causes_______________  
R  - GAPCU (24XG)  
R  - wiring  
R  - C/B-GND/PWR/PROT (2XG)  
R  - feeders  
R  2. Job Set-up Information______________________  
R  A. Referenced Information  
R  ------------------------------------------------------------------------------- 
R  REFERENCE  DESIGNATION  
R  -------------------------------------------------------------------------------
R  AMM  24-41-00-861-002  
R  
R  AMM  24-41-00-862-002  
R  
R  AMM  24-41-34-000-001  
R  
R  AMM  24-41-34-400-001  
R  
R  ASM  24-41/01 
R 3. Fault Confirmation
__________________ 
Energize the Aircraft Electrical Circuits from the External Power De-energize the Aircraft Electrical Circuits Supplied from the External Power Removal of the Ground Auxiliary Power Control Unit (GAPCU) (24XG) Installation of the Ground Auxiliary Power Control Unit (GAPCU) (24XG) 
R  A. If the external power source is connected to the aircraft electrical  
R  circuits while a different source supplies the aircraft electrical  
R  circuits (IDG, APU, batteries):  
R  - on the ELEC panel 35VU, release, push and release again the ELEC/EXT  
R  PWR pushbutton switch (10XG) to do a reset of the GAPCU protection  
R  function. Then close the interlock on the Ground Power Unit (GPU).  
R  (1) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG)  
R  comes on and if on the ELEC panel 35VU, the AVAIL legend of the  
R  ELEC/EXT PWR pushbutton switch (10XG) comes on:  
R  - stop the trouble shooting.  
R  (2) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG)  
R  stays off and if on the ELEC panel 35VU, the AVAIL legend of the  
R  ELEC/EXT PWR pushbutton switch (10XG) stays off:  
R  - do the trouble shooting given in Para. 4.B.
R B. If the external power source is connected to the aircraft electrical 
R circuits with no other source(s) connected (IDG, APU, batteries): 
R - on the ELEC panel 35VU, push the BAT 1 and BAT 2 pushbutton switches 
R (7PB1 and 7PB2) (on the MCDU menu page, make sure that the CFDS 
R indication comes into view). 
R - on the ELEC panel 35VU, release, push and release again the ELEC/EXT 
R PWR pushbutton switch (10XG) to do a reset of the GAPCU protection 
R function. Then close the interlock on the Ground Power Unit (GPU).
R (1) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG) 
R comes on and if on the ELEC panel 35VU, the AVAIL legend of the 
R ELEC/EXT PWR pushbutton switch (10XG) comes on: 
R - stop the trouble shooting.
R (2) If on the EXT PWR panel 108VU, the EXT PWR/AVAIL caution light (9XG) 
R stays off and if on the ELEC panel 35VU, the AVAIL legend of the 
R ELEC/EXT PWR pushbutton switch (10XG) stays off: 
R - do the trouble shooting given in Para. 4B.
R 4. Fault Isolation
_______________ 
R A. Table of the circuit breakers used in this procedure:
R -------------------------------------------------------------------------------R PANEL DESIGNATION IDENT. LOCATION 
R -------------------------------------------------------------------------------R 123VU GND/PWR/PROT 2XG AB07
R B. If the test confirms the fault: 
R - on the AC power center panel 123VU, do a check of the status of the 
R GND/PWR/PROT circuit breaker (2XG).
R (1) If the circuit breaker (2XG) is open: 
R - close it 
R - close the interlock on the GPU.
R (a) If the circuit breaker (2XG) trips: 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址:A320 Trouble Shooting Manual 排故手册 电源 3(99)