190-01007-A1 System Maintenance Manual GTN 6XX/7XX Part 23 AML STC
Rev. 7 Page 5-9
5.3.1.1 COM Related Alerts
Table 5-3. COM Alert Troubleshooting Guide
Alert Text Possible Cause Corrective Action
COM RADIO - COM
radio needs service.
A failure has been detected in the COM
transceiver. The transceiver may still
be usable.
This message may appear after
operations in configuration mode.
Cycle power to the entire GTN (both
GPS/NAV and COM circuit breakers)
and see if the message has cleared.
Contact Garmin technical support.
COM RADIO - COM
radio may be
inoperative.
The GTN is not able to communicate
with its COM transceiver.
Verify that COM connector pins
P1003-43 and P1004-44 are receiving
aircraft power.
Verify that COM connector pins
P1003-37 and P1003-38 are
connected to aircraft ground.
If the message persists, contact
Garmin technical support.
REMOTE KEY STUCK
- COM push-to-talk key
is stuck.
The COM push-to-talk switch is stuck
in the enabled or pressed state.
Press the PTT switch to cycle its
operation.
If the message persists, contact
Garmin technical support.
Go to the GTN DIAGNOSTICS -
DISCRETE INPUTS page in
configuration mode and check that the
state of the input changes when the
PTT switch is pressed and released.
Verify that the PTT switch wiring is
correct.
REMOTE KEY STUCK
- COM remote transfer
key is stuck.
The COM remote transfer key is stuck
in the enabled or pressed state.
Go to the GTN DIAGNOSTICS -
DISCRETE INPUTS page in
configuration mode and check that the
state of the input changes when the
COM remote frequency increment
switch is pressed and released.
Verify that the COM remote frequency
increment switch wiring is correct.
Press the COM remote transfer switch
to cycle its operation.
If the problem persists, contact
Garmin technical support.