Garmin GNS 480, Инструкция по установке

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Troubleshooting
GNS 480 (CNX80) Installation Manual 560-0982-01 Rev L 4-1
4 Troubleshooting
This section provides information to assist troubleshooting if problems occur after completing the
installation. Use Table 4-1 to assist in troubleshooting. Devices connected to the GNS 480, such as an
SL30, SL70 or MX20/GMX 200 can be useful for determining whether the GNS 480 is functioning
properly or if there are problems with the installation.
4.1 Troubleshooting Procedure
Table 4-1. Troubleshooting Guide
Problem Possible Cause Solution
The GNS 480 does not
power on.
•
The unit is not getting power to the
main connector P1.
•
Make sure power is connected to the
main 37-pin connector P1-1 and 16 and
ground to P1-2 and 20. Check circuit,
breakers and main avionics switch.
The GNS 480 does not
compute a position.
•
Not receiving signals, or incorrect
seed position, time, and date.
•
Make sure a correct position and
time/date have been entered. Check the
GPS antenna connections. Make sure the
aircraft is clear of hangers, buildings,
trees, etc.
GPS signal levels drop
when avionics are
turned on.
•
Noise interference from other
avionics.
•
Turn all avionics off, then turn on each
piece one at a time to isolate the source
of the interference. Route GPS cable and
locate GPS antenna away from sources
of interference.
•
Improper antenna installation or
coax routing.
•
Check GPS antenna installation,
connections, and cable routing. The GPS
antenna must be mounted on the top of
the aircraft.
•
Antenna shaded from satellites.
•
Make sure the aircraft is clear of
hangars, buildings, trees, etc.
The GPS signal levels
are very low.
•
RF interference at 1575.42 MHz
from VHF COM.
•
Move GPS antenna further from the
COM antenna. Add a 1575.42 MHz
notch filter in COM coax. Fix or replace
the COM. Disconnect the ELT antenna
coax to check for possible re-radiation.
•
No power to the COM.
•
Make sure power is connected to the
COM 15-pin connector P4-1 and ground
to P4-9.
Unable to control
COM using
COM
bezel key.
•
The input voltage is too low.
•
Increase input supply voltage to > 10
volts DC.
•
The PTT input is not being pulled
low.
•
Check that the PTT (mic key) input is
pulled low for transmit.
•
No power to the COM.
•
Make sure power input is connected to
the COM 15-pin connector P4-1 and
ground to P4-9.
The GNS 480 does not
transmit.
•
The input voltage is too low.
•
Increase input supply voltage to > 10
volts DC.