Installation manual

Troubleshooting
52 Apollo MX20 Installation Manual
Table 10 - Troubleshooting Guide
Problem Cause Solution
5. Position source not configured
on appropriate port.
6. External GPS not properly
configured.
7. RF interference.
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.
Unit shows RTE data flag. External position source does not
have active route engaged.
Ensure that the external position
source has an active route engaged.
Unit shows ALT data flag. 1. Data port configuration
incorrect.
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. Ensure that the data port
configuration is 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.
Unit shows TER data flag. 1. Terrain database incorrect.
2. Invalid altitude supplied to unit.
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).
SL30 information is not
displayed.
1. Data port configuration
incorrect.
2. SL30 is not powered up.
3. Wiring connections are incorrect.
1. Ensure that the data port
configuration is correct and
matches how the unit is wired for
the SL30.
2. Ensure the SL30 has power
applied.
3. Check wiring.
Unit shows DEMO data flag. Demo mode enabled. Ensure that demo mode is not