Garmin Apollo CNX80 Installation Manual page 108

Troubleshooting
Problem
• The PTT input is not being pulled
The CNX80 does not
transmit.
• No power to the com.
• The input voltage is too low.
• Wrong type of headsets, or level
The sidetone level is
too low or too high.
• No power to the nav receiver.
Unable to control Nav
using bezel key.
VOR
• Incompatible resolver or improper
OBS Resolver won't
calibrate.
• CNX80 resolver input not
OBS indication on
CNX80 does not agree
with OBS setting
• Resolver has not been calibrated.
• Message audio volume level set
CNX80 Message
Audio or Tone not
heard
• Message tone is turned OFF.
• Audio inhibit line grounded
• SL70/SL70R transponder is not
Unable to control
transponder using
bezel key.
XPDR
• SL70 is not configured correctly.
• Wiring connections are incorrect.
• Incorrect configuration used for
CNX80 not receiving
baro correction data
from MX20.
• MX20 software prior to v5.x.
• Wiring connections are incorrect.
4-2
Table 4-1. Troubleshooting Guide
Possible Cause
low.
needs adjustment.
connection.
configured correctly.
too low
turned on.
serial port to MX20.
560-0982-00 Rev D
Solution
•
Check that the PTT (mic key) input is
pulled low for transmit.
•
Make sure power input is connected to
the com 15-pin connector P4-1 and
ground to P4-9.
•
Increase input supply voltage to > 10
volts DC.
•
If necessary, adjust the sidetone level.
Sidetone adjustment is found under the
AUDIO menu in the COM function.
•
Make sure power is connected to the
nav 37-pin connector P7-1 and ground
to P7-2.
•
Check the resolver specifications and
wiring.
•
Check resolver configuration in Ground
Maintenance Mode
•
Calibrate resolver
•
Increase AMA volume level. AMA
adjustment is found under the AUDIO
menu in the COM function.
•
Turn message tone ON via system
configuration page.
•
Verify that inhibit input (P5-77) is not
grounded using Ground Maintenance
Mode.
•
Turn on transponder
•
Go to serial port setup page and verify
that RS232 port 6 has SL70 set for both
CH 6 RX and CH 6 TX.
•
Check wiring.
•
Go to serial port setup page and verify
that RS232 port 1 has MAPMX set for
both CH 1 RX and CH 1 TX (only
MX20 version 5.x or later supports the
MAPMX protocol).
•
Update MX20 software.
•
Check wiring
Apollo CNX80 Installation Manual