Garmin Apollo CNX80 Installation Manaul - page 128
Troubleshooting
4-2
560-0982-01 Rev L
GNS 480 (CNX80) Installation Manual
Table 4-1. Troubleshooting Guide
Problem Possible
Cause
Solution
The sidetone level is
too low or too high.
• Wrong type of headsets, or level
needs adjustment.
• If necessary, adjust the sidetone level.
Sidetone adjustment is found under the
AUDIO menu in the COM function.
Unable to control NAV
using
VOR
bezel key.
• No power to the nav receiver.
• Make sure power is connected to the nav
37-pin connector P7-1 and ground to P7-
2.
OBS Resolver won’t
calibrate.
• Incompatible resolver or improper
connection.
• Check the resolver specifications and
wiring.
• GNS 480 resolver input not
configured correctly.
• Check resolver configuration in Ground
Maintenance Mode
OBS indication on
GNS 480 does not
agree with OBS setting • Resolver has not been calibrated. • Calibrate resolver
• Message audio volume level set too
low
• Increase AMA volume level. AMA
adjustment is found under the AUDIO
menu in the COM function.
• Message tone is turned OFF.
• Turn message tone ON via system
configuration page.
GNS 480 Message
Audio or Tone not
heard
• Audio inhibit line grounded
• Verify that inhibit input (P5-77) is not
grounded using Ground Maintenance
Mode.
• SL70/SL70R transponder is not
turned on.
• Turn on transponder
• SL70 is not configured correctly. • Go to serial port setup page and verify
that RS-232 port 6 has SL70 set for both
CH 6 RX and CH 6 TX.
Unable to control
transponder using
XPDR
bezel key.
• Wiring connections are incorrect. • Check wiring.
• Incorrect configuration used for
serial port to MX20/GMX 200.
• Go to serial port setup page and verify
that RS-232 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).
• MX20 software prior to v5.x.
• Update MX20 software.
GNS 480 not receiving
baro correction data
from MX20/GMX 200.
• Wiring connections are incorrect. • Check wiring
• The GNS 480 is not configured
correctly.
• Go to serial port setup page and verify
that RS-232 port to SL30 is set to SL30
on RX and MAPCOM on TX.
DST data (Distance,
Speed, Time) is not
displayed on the SL30.
• The SL30 is not set up for DST
display.
• Consult SL30 users guide for setup of
DST display.