Garmin G1000 Line Maintenance Manual page 142

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4.7.3.7.7 Dual GPS Antenna Troubleshooting
In some dual GPS installations, a single failed antenna can cause both GPS systems to
drop satellites. In this case, failure of one antenna interferes with, but does not cause
damage to the working antenna. The following steps might be helpful in troubleshooting
to identify the failed antenna in dual GPS installations.
NOTE
Some antennas might fail intermittently depending on temperature or
altitude.
Test the antenna as follows:
1. For dual installations, turn on and monitor the GPS status of both installed units
on the GPS Status Pane.
2. If GPS1 signal strength bars are erratic/weak, open the GIA2 and COM2 circuit
breakers. If the problem is resolved, the GPS2 antenna has failed. If the GPS2
signal strength bars are erratic/weak, open the GIA1 and COM2 circuit breakers.
If problem is resolved, the GPS1 antenna has failed.
3. Contact Garmin Aviation Product Support for a replacement antenna. Return the
failed antenna to Garmin for engineering evaluation.
4.7.3.8 NAV Troubleshooting
4.7.3.8.1 Weak NAV Receiver
1. Set up a NAV/COM ramp test set to radiate a test signal.
2. Switch GIA1 and GIA2 to verify the location of the problem.
3. If the problem follows the unit, replace the GIA.
4. If the problem does not follow the unit; check the NAV antenna, coupler, and
cabling for faults.
4.7.3.8.2 Weak Glideslope Receiver
1. Set up a NAV/COM ramp test set to radiate a test signal.
2. Switch GIA1 and GIA2 to verify the location of the problem.
3. If the problem follows the unit, replace the GIA.
4. If the problem does not follow the unit; check the NAV antenna, coupler, and
cabling for faults.
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Page 4-58 LMM for the Kodiak 100
190-02102-00 Rev.4