Garmin MX20 Installation Manual page 70

Troubleshooting
Problem
Unit shows POS data flag
(cont'd).
Unit shows RTE data flag.
Unit shows ALT data flag.
Unit shows TER data flag.
60
Table 5-1. Troubleshooting Guide Cont'd
Cause
4. Waypoint not selected as the
current destination.
5. Position source not configured on
appropriate port.
6. External GPS not properly
configured.
7. RF interference.
1. External position source does not
have active route engaged.
1. Data port configuration incorrect. 1. Ensure that the data port configuration is
2. Serial altitude encoder not
powered up; not functioning
properly.
3. System is configured to use GX
unit as source for altitude data
and GX is not turned on.
4. System is configured to use GX
unit as source for altitude data
and GX not configured properly.
1. Terrain database incorrect.
2. Invalid altitude supplied to unit.
560-1025-09 Rev E
Solution
4. If a GX/SL series is used as the position
source, ensure that a waypoint is selected as the
current destination (Nav Flagged is not shown
on primary Nav page).
5. If a GX/SL series is used as the position
source, ensure that it is configured to
output serial data (MOV MAP) on the
appropriate port.
6. If other compatible external GPS is used,
ensure it is configured to output serial
position data on the appropriate lines.
7. Ensure no RF interference at 1575 MHz
from VHF Comm antenna – add 1575
MHz notch filter in Comm coax; Fix or
replace Comm; Disconnect the ELT
antenna coax to check.
1. Ensure that the external position source
has an active route engaged.
correct and matches how the unit is wired
for the serial altitude source.
2.
Ensure that serial altitude encoder is
powered up and functioning properly.
3. Ensure GX is turned on, shows a valid
altitude, and has acquired position and
valid waypoint.
4.
Verify that GX has extended data output
enabled.
1. Ensure the unit has the appropriate
terrain database loaded for the area of
operation. The terrain database is
indicated on the power-up and system
status pages of the MX20.
2. Ensure that valid altitude is being supplied to
the unit (an ALT data flag should not be
present).
MX20 Installation Manual