Garmin AT
Rev --
© 2004 Garmin AT
GX Service Manual
9-5
SYMPTOM CAUSE
ACTION
No serial data out
1. User configuration
2. A/C
Installation
3. NAV
board
1. Verify
user
configuration.
2. Check A/C installation.
3. Replace the NAV board. (See NAV
Board Replacement procedure.)
Noise in headset
1. Connections
2. User
configuration
3. Comm
board
1. Verify headset with another.
2. Verify
user
configuration.
3. Replace Comm board. (See Comm
Board Replacement procedure.)
Not flip/flopping
frequencies
1. Remote
frequency
switch
2. No power to Comm
board
3. Comm to NAV cable
4. Comm
board
1. Check remote switch operation.
2. Verify A/C power and ground to
Comm board.
3. Check fuse (F400) on Comm board.
4. Verify 8-pin NAV to Comm
connections (Comm J4 to NAV
J606).
5. Replace Comm board. (See Comm
Board Replacement procedure.)
RX audio distortion
1. Radio interference
2. Antenna
connections
3. Comm
board
1. Verify
area/instrument
interference
is not the cause.
2. Check the antenna.
3. Replace Comm board. (See Comm
Board Replacement procedure.)
Stuck in simulation mode
1. A/C installation
2. NAV
board
1. Verify pin 7 of 37 pin D-sub
connector (P701) is grounded.
2. Replace the NAV board. (See NAV
Board Replacement procedure.)
Soft key inoperative
1. Software version 1.0
2. Soft key flex cable or
connection
3. Display
assembly
1. Check all soft keys in normal
operation.
2. Ensure that soft key flex cable is
connected.
3. Replace display assembly. (See
Display Replacement procedure).
Resets on low map
settings
Software version 1.0
Replace the NAV board. (See NAV
Board Replacement procedure.)
Unit intermittent below 20
on the map scale
Software version 1.0
Replace the NAV board. (See NAV
Board Replacement procedure.)
When in approach, will
not display baro & give alt
error
Software version 1.0
1. Replace the NAV board. (See NAV
Board Replacement procedure.)
2. Verify good 3-D fix.
Display flashes
continuously under
certain light conditions
Software version 1.0
Replace the NAV board. (See NAV
Board Replacement procedure.)
Summary of Contents for APOLLO GX SERIES
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