(b)
Put the SET switch to MS (minute slew).
1) Make sure that the Captain's GMT indicator changes 1 minute for each second.
(c)
Put the SET switch to RUN.
(d)
Push the CLOCK switch on the Captain's glare shield. 1) Make sure that the second hand turns from 12 o'clock.
(e)
Stop while the second hand completes 2 turns.
(f)
Push the CHR switch of the clock. 1) Make sure that the second hand stops to turn.
(g)
Push the CLOCK switch on the Captain's glare shield. 1) Make sure that the second hand stops at 12 o'clock.
(h)
Open the 6H17 CLOCK DISP circuit breaker on the panel P6. 1) Make sure that each display is off.
(i)
Stop for 5 minutes.
(j)
Close the 6H17 CLOCK DISP circuit breaker on the panel P6.
1) Make sure that the GMT continued to change during the 5 minute stop.
S 715-007
(2) Do the test of the first officer's clock:
(a)
Put the SET switch to HS (hour slew).
1) Make sure that the First Officer's GMT display changes 1 hour for each second.
(b)
Put the SET switch to MS (minute slew).
1) Make sure that the First Officer's GMT display changes at 1 minute for each second.
(c)
Put the SET control to RUN.
(d)
Push the CLOCK switch on the First Officer's glare shield.
1) Make sure that the second hand starts to move from 12 o'clock.
(e)
Stop while the second hand completes 2 turns.
(f)
Push the CHR switch of the clock. 1) Make sure that the second hand stops to turn.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
31-25-00
ALL ú ú 01 Page 502 ú Oct 10/92
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
(g)
Push the CLOCK switch on the First Officer's glare shield. 1) Make sure that the second hand stops at 12 o'clock.
(h)
Open the 6H17 CLOCK DISP circuit breaker on the panel P6. 1) Make sure that each display is off.
(i)
Stop for 5 minutes.
(j)
Close the 6H17 CLOCK DISP circuit breaker on the panel P6.
1) Make sure that the GMT continued to change during the 5 minute stop.
S 865-009
(3) Remove electrical power if it is not necessary (AMM 24-22-00/201).
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
31-25-00
ALL ú ú 01 Page 503 ú Jun 18/01
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
CLOCKS - REMOVAL/INSTALLATION
_____________________________
1. General_______
A. Two tasks are provided in this subject.
(1)
The first task removes a clock from the airplane.
(2)
The second task installs the replacement clock on the airplane and does an operational test of that clock.
B. Two clocks are installed in the airplane.
(1)
One clock (N143) is installed in the Captain's instrument panel P1.
(2)
One clock (N146) is installed in the First Officer's instrument panel P3.
TASK 31-25-01-004-001
2. Clock Removal_____________
A. Access
(1) Location Zone
221 Flight Compartment, Left
222 Flight Compartment, Right
B. Procedure
S 864-002
(1) Open each circuit breaker that follows and attach DO-NOT-CLOSE tags:
(a) P6 Main Power Distribution Panel
1) 6H08 ELEX CLOCK
2) 6H17 CLOCK DISP
S 034-003
(2)
Loosen the mounting clamp screws to remove the clock.
