S 715-013
(3)
Do a test on the relays of the left and the right utility bus as follows:
(a)
Supply external power to the main AC buses (AMM 24-22-00/201).
(b)
Push the switches of the left the and right UTILITY BUS to the ON position. 1) Make sure the white ON lights are on. 2) Make sure the yellow OFF lights are off. 3) Make sure the EICAS display does not show a UTIL BUS OFF
indication.
(c)
Push the switches of the L and (R) UTILITY BUS to the OFF position. 1) Make sure the yellow OFF lights are on. 2) Make sure the L and (R) UTIL BUS OFF indications are shown
on the upper EICAS display.
(d)
Remove electrical power if it is not necessary
(AMM 24-22-00/201).
S 715-014
(4) Do a test on the ground service transfer relay as follows:
(a) Supply external power to the ground service bus
(AMM 24-22-00/201).
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MAINTENANCE MANUAL
(b)
Make sure the 115 GND SVCE HOT BUS WARNING light on the P37 panel is on.
(c)
Remove electrical power if it is not necessary (AMM 24-22-00/201).
S 715-015
(5) Do a test on the ground service select relay as follows:
(a)
Supply APU power to the ground service bus (AMM 24-22-00/201).
(b)
Make sure the 115 GND SVCE HOT BUS WARNING light on the P37 panel is on.
S 865-016
(6)
Remove the APU electrical power if it is not necessary (AMM 24-22-00/201).
S 445-017
(7)
Do the activation procedure for the spoilers (AMM 27-61-00/201) if previously deactivated.
TASK 24-50-00-725-002
3. System Test
___________
A. Equipment
(1)
Multimeter, |5% accuracy, used to measure 115
volts AC, 28 volts AC, and 28 volts DC.
(2)
Adapter relay - P/N A24004-2
B. References
(1)
AMM 24-22-00/201, Electrical Power - Control
(2)
AMM 27-61-00/201, Spoiler/Speedbrake Control System
C. Access
(1)
Location Zones
119/120 Main Equipment Center
211/212 Flight Compartment
(2)
Access Panel
119AL Main Equipment Center
D. Prepare for the Test
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S 045-018
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.
E. System Test - Electrical Power Distribution
S 725-048
WARNING:_______EXERCISE CARE WHEN WORKING IN THE POWER PANELS. VOLTAGES PRESENT CAN CAUSE SERIOUS INJURY AND/OR DAMAGE TO EQUIPMENT.
(1)
Do a test on the center bus transfer relay as follows:
(a)
Remove the isolation request relay from the P6 panel.
(b)
Install the relay adapter in the isolation request relay socket, and set the switch on the adapter to ON.
(c)
Set the multimeter to measure 28 volts DC. Connect the meter to terminal B of FLT CONT CMPTR DC C (11E20, C518) circuit breaker and ground.
(d)
Supply electrical power to the left main AC bus (AMM 24-22-00/201).
(e)
Measure 24 |4 volts DC.
(f)
Open this P6 panel circuit breaker:
1) 6L12, CENTER BUS DC
(g)
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