Garmin APOLLO GX SERIES, Service Manual

Page: 126 / 166

Garmin AT Rev --
9-4 GX Service Manual © 2004 Garmin AT
SYMPTOM CAUSE ACTION
Data/list knob inoperative,
OR
skips windows when
turning knobs
Display assembly Replace display assembly. (See Display
Replacement procedure.)
Display reset 1. Intermittent A/C power
connections
2. NAV board
1. Verify A/C power & ground
connections.
2. Initialize the unit.
3. Replace the NAV board. (See NAV
Board Replacement procedure.)
Power cycles on and off 1. Aircraft power
connections.
2. Power supply.
3. NAV board.
1. Verify aircraft wiring.
2. Test the unit on the bench.
3. Replace the NAV board. (See NAV
Board Replacement procedure.)
Resets itself in flight See power cycles on and
off – above. See power cycles on and off – above.
Intercom not keying 1. User setup not
properly configured
2. A/C installation
3. Comm board
1. Verify user set-ups and squelch
levels to current spec. (See user
setup procedure in the user’s
manual).
2. Replace Comm board. (See Comm
Board Replacement procedure.)
Low transmit power
No Tx
No Rx
1. Antenna connections
2. Antenna
3. Comm board
1. Check antenna and cable.
2. Replace Comm board. (See Comm
Board Replacement procedure.)
No antenna voltage 1. Connections
2. Short in antenna cable
3. GPS receiver
4. Antenna
5. Comm board
1. Check antenna coax connections.
2. Check for coax short to shield.
3. Replace GPS receiver. (See the
GPS Board Replacement procedure
for the unit.)
4. Replace GPS antenna.
No aviation output (CDI,
To/Fr) 1. Connections/
installation
2. Annunciator
3. NAV board
1. Check installation.
2. Check the output device (CDI, etc.).
3. Replace the NAV board. (See NAV
Board Replacement procedure.)
No power/dead 1. No aircraft power
2. Fuse
3. Display
4. NAV board
1. Check A/C power and ground.
2. Check NAV fuse F701.
3. Check display (swap it out). (See
Display Replacement procedure.)
4. Replace the NAV board. (See NAV
Board Replacement procedure.)