SKY899
Installation Manual
Page 4-24 - Maintenance
009-11900-001
July 18, 2013
Revision F
4.5 TROUBLESHOOTING
Table 4-2 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, the service menu must be accessed via an RS-232
terminal device, see Appendix E for operating instructions.
Table 4-2: Fault Isolation
SYMPTOM
CORRECTIVE ACTION
RF Failure (error 12) or antenna calibration screen displays
an invalid BIT phase during the calibration procedure.
a. Verify antenna location and type was correctly set during
setup.
b. Calibrate antenna by selecting calibration from setup
menu. Verify BIT phase shows a number and not an
invalid message.
c. Check directional antenna and associated cables.
Display remains dark after SKY899 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 (18 - 32 V dc PWR)
P8-B +28V_RET (AIRCRAFT PWR RETURN)
Check cables connected to display.
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).
SKY899 will not enter service menu.
a. If using an WX-1000/SKY497 display check soft-key
wiring.
b. If using an alternate display service menu must be
accessed with an RS-232 terminal device. (Appendix E)
The self-test successfully completes without audio
annunciation.
a. Check headphones/speaker and aircraft audio panel
switch settings.
b. Check volume level and run audio test in service menu.
c. Check cables connected to TRC.
Audio Alert Output:
P1-89 (AUDIO_H - 600-Ohm)
P1-90 (AUDIO_L - 150-Ohm)
P1-91 (AUDIO_C - Common)
SKY899 Failed.
a. Check system log (para 4.4.2.2) 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 squat switch connection to the TRC and the
weight-on-wheels configuration in service menu.
Squat Switch Input: P1-24
The display cannot be switched between SKY899 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 2.24.1 and figure 2-2).
The document reference is online, please check the correspondence between the online documentation and the printed version.
