Install Manual Part 3

SKY497
Installation Manual
4-14
Rev. C
4.5 TROUBLESHOOTING
Table 4-1 is intended to assist trained electronic technicians to determine which assembly is inoperative.
Do the corrective action steps in the order described. Use the Service Menu (refer to paragraph 4.4) as an
aid in fault isolation. Information available from the service menu can help identify conditions that need to
be resolved. If interfaced to an alternate display service menu must be accessed via an RS-232 terminal
device, see Appendix D for operating instructions.
Table 4-1. Fault Isolation
SYMPTOM CORRECTIVE ACTION
Display remains dark after SKYWATCH is powered ON.
a. Check position of the WX-1000 maintenance switch
(NORMAL/OVERRIDE).
b. Reset circuit breaker if it is tripped.
c. Check aircraft power source.
d. Check connection to WX-1000 processor, if installed.
e. Check power input at TRC mating connector.
P8-A +28V (10.5-34V PWR)
P8-B +28V_RET (AIRCRAFT PWR RETURN)
f. Check cables connected to display.
g. Replace Display.
Display is distorted.
Check for interference from aircraft systems.
Incorrect response to buttons (soft-keys).
Check soft-key wiring inside display cable and WX-1000
processor cable (if installed).
SKYWATCH will not enter service menu.
a. Check soft-key wiring.
b. Verify alternate display pins (P1-77, P1-78, P1-79, or
P1-80) are not configured to ground. Service menu is
not accessible via softkeys when an alternate display is
configured.
c. If using an alternate display service menu must be
accessed via an RS-232 terminal device.
The self-test successfully completes without audio
annunciation.
a. Check headphones/speaker and aircraft audio panel
switch settings.
b. Check cables connected to TRC.
Audio Alert Output:
P1-92 (AUDIO_H - 600-Ohm)
P1-91 (AUDIO_L - 150-Ohm)
P1-90 (AUDIO_C - Common)
SKYWATCH Failed.
a. Check system log (para 4.4.2) for errors. Error
messages are detailed in para 4.6.
b. Replace TRC.
Self-test does not execute. Aircraft is on the ground.
a. If standby screen is displayed, check soft-key wiring
inside display cable and WX-1000 processor cable
(if installed).
b. Check connection between the TRC and the squat
switch sensor.
Squat Switch Input: P1-88
The display cannot be switched between SKYWATCH and
the WX-1000. Both systems are installed.
a. Check circuit breakers. Reset if tripped.
b. Check position of the WX-1000 maintenance switch
(SW2). It should be set to the NORMAL position.
c. Check wiring of the SKYWATCH/
Stormscope display
mode switch (para 2.6.11/figure 2-2).
WX-1000 processor has been removed for service;
SKYWATCH fails to operate.
Check position of the WX-1000 maintenance switch
(NORMAL/OVERRIDE). When the WX-1000 has been
removed for service, it should be set to the OVERRIDE
position. This switch may be located in the avionics bay.