Garmin GNS 480 Installation Manaul page 128

Troubleshooting
Problem
• 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
VOR
using bezel key.
• Incompatible resolver or improper
OBS Resolver won't
calibrate.
• GNS 480 resolver input not
OBS indication on
GNS 480 does not
agree with OBS setting
• Resolver has not been calibrated.
• Message audio volume level set too
GNS 480 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
XPDR
bezel key.
• SL70 is not configured correctly.
• Wiring connections are incorrect.
• Incorrect configuration used for
GNS 480 not receiving
baro correction data
from MX20/GMX 200.
• MX20 software prior to v5.x.
• Wiring connections are incorrect.
• The GNS 480 is not configured
DST data (Distance,
Speed, Time) is not
displayed on the SL30.
• The SL30 is not set up for DST
4-2
Table 4-1. Troubleshooting Guide
Possible Cause
needs adjustment.
connection.
configured correctly.
low
turned on.
serial port to MX20/GMX 200.
correctly.
display.
560-0982-01 Rev L
Solution
•
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 RS-232 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 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).
•
Update MX20 software.
•
Check wiring
•
Go to serial port setup page and verify
that RS-232 port to SL30 is set to SL30
on RX and MAPCOM on TX.
•
Consult SL30 users guide for setup of
DST display.
GNS 480 (CNX80) Installation Manual