TM 55-1520-240-T
9-22.3 CLOCK OPERATIONAL CHECK
9-22.
3
INITIAL SETUP
References:
Applicable Configurations:
TM 55-1520-240-23
With
TM 55-1520-240-10
Tools:
Equipment Condition:
None
TM 55-1520-240-23:
Battery Connected
Materials:
Electrical Power On
None
Hydraulic Power Off
Personnel Required:
Visual Check of Clock Performed (Task 9-22.2)
Aircraft Electrician
TASK
RESULT
1. Check that PLT CLOCK circuit breaker (1)
If PLT CLOCK circuit breaker (1) is open, close it. If it
is closed.
opens again, go to task 9-22.4.
2. Check that CPLT CLOCK circuit breaker
If CPLT CLOCK circuit breaker (2) is open, close it. If
(2) is closed.
it opens again, go to task 9-22.5.
3. Check GMT display (3) on pilot and co-
GMT display (3) shall indicate greenwich mean time.
pilot clocks (4) and (5).
If display is blank, replace battery on back of clock
and set clock. Refer to TM 55-1520-240-20 for set-
ting instructions.
4. Press and hold SELECT button (6) on pilot’s
Clock display (7) shall indicate 88:88 and annuncia-
clock (4) for three seconds.
tors (8) shall light. If display does not indicate 88:88
and annunciators are not lit, go to task 9-22.6.
5. Rotate DIM control (9) on pilot’s clock
Clock display brightness shall vary. If it does
(4).
not, replace pilot’s clock.
6. Press and hold SELECT button (6) on copilot’s
Clock display (7) shall indicate 88:88 and annuncia-
clock (5) for three seconds.
tors (8) shall light. If display does not indicate 88:88
and annunciators are not lit, go to task 9-22.7.
7. Rotate DIM control (9) on copilot’s clock
Clock display brightness shall vary. If it does not,
(5).
replace copilot’s clock.
FOLLOW-ON MAINTENANCE:
TM 55-1520-240-23:
Battery Disconnected
Electrical Power Off
9-368
Change 2
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