(e)  
Remove the external power from the ground service bus.

 (f)  
Supply the external power to the 115V ac buses:

 NOTE: The ground handling bus energizes automatically when the
____ external power is supplied to the receptacle. The ground service bus is energized automatically when the external power is supplied to the right 115V ac bus.
 (g)  Remove the external power from the 115V ac buses.
 B. References
 (1) AMM 27-61-00/201, Spoiler/Speedbrake Control System
 C. Equipment
 (1)  External power supply - 115/200-volt ac,
 3-phase, 400-Hz, 90-Kva

 D. Access
 (1)  
Location Zones
 212 Flight Compartment

 (2)  
Access Panel
 120AR External Power Panel

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 E.  Prepare for the Test
 S 042-030
 WARNING: DO THE DEACTIVATION PROCEDURE FOR THE SPOILERS OR MOVE ALL
_______ PERSONS AND EQUIPMENT AWAY FROM THE SPOILERS. THE SPOILERS CAN RETRACT QUICKLY AND CAUSE INJURY TO PERSONS OR DAMAGE TO EQUIPMENT.
 (1)  Do the deactivation procedure for the spoilers (AMM 27-61-00/201) or move all persons and equipment away from the spoilers. If the spoilers are extended and electrical power is removed, the spoilers will retract in less than one second.
 F.  Procedure
 S 862-031
 (1)  Do these steps to reset the ground handling relay (GHR):
 (a)  If the electrical power on the ground handling bus is suddenly lost while the external power cable is still energized and connected to the external power receptacle, do one of these procedures to reset the GHR:
 NOTE:____If the BPCU senses any one of these faults: an open phase, over current, differential fault, over/under frequency, over/under voltage or internal failure of BPCU, the external power is removed from the ground handling bus. You must do one of the reset procedures to supply the power to the ground handling bus.
 1)  Remove and install the electrical power plug from/to the 120AR External Power Panel: a) Remove the electrical power from the external power
 cable.
 b)  Remove the external power cable from the receptacle.
 c)  Install the external power cable in the external power
 receptacle.
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 d) Use a cargo tie down to support the cable. e) Energize the power cable. 2) Remove and supply the electrical power to the BPCU: a) Remove the electrical power from the external power
 cable. b) Set the BAT switch (P5) to the OFF position. c) Energize the external power cable.
 3) Operate the GRND SERV BUS Switch : a) Make sure the external power plug is connected to the receptacle. b) Make sure the CONNECTED light in the receptacle panel P30 is on. c) Push and release the GRND SERV BUS switch on the P21 panel.
 S 862-032
 (2)  Do these steps to supply the external power to the ground handling bus:
 (a)  Open the cover on the external power panel P30.
 WARNING: IF THE EXTERNAL POWER SUPPLY HAS AN EARTH GROUNDED
_______ NEUTRAL, THERE MUST NOT BE AN OPEN OR FLOATING GROUND IN THE NEUTRAL CIRCUIT WIRING OF THE SUPPLY OR THE AIRPLANE. IF AN OPEN OR FLOATING GROUND IS PRESENT, THE AIRPLANE CAN BE PUT AT AN ELECTRICAL POTENTIAL ABOVE EARTH GROUND. THIS ELECTRICAL POTENTIAL CAN RESULT IN ELECTRIC SHOCK WITH POSSIBLE SEVERE INJURY TO PERSONNEL WHO TOUCH THE AIRPLANE.
 (b)  Make sure the external power supply operates correctly before you supply external power to the airplane. 1) If the ground return (neutral) circuit on the external
 power supply or the external power receptacle does not operate correctly, do this task: Static Grounding (AMM 24-41-01/401).
 WARNING: REMOVE THE ELECTRICAL POWER FROM THE EXTERNAL POWER CABLE
　
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