Fault Isolation; Table 6. Elt Self-Test Error Codes Troubleshooting Guide; Self-Test Error Troubleshooting Guidelines - ACR Electronics Cobham C406-1 Series Abbreviated Component Maintenance Manual

TASK 25-62-10-810-801

3. Fault Isolation

SUBTASK 25-62-10-810-001
A.

Self-Test Error Troubleshooting Guidelines

(1) Table 6 describes the ELT self-test LED error codes (i.e., flash codes), their probable causes,
and possible solutions. The 5-flash error is not present when the ELT is programmed with a
serial user protocol (short message).
NOTE:

Table 6. ELT Self-Test Error Codes Troubleshooting Guide

CODE
Remote switch harness connector loose or
1-Flash
ELT connector pins bent or broken
Connector pins 5 and 8 jumper open
(internal to remote switch harness
Open or short condition on antenna
3-Flash
Impedance presented by antenna
Upright metal structure obstructing
COBHAM AVIONICS WULFSBERG ELECTRONICS
ABBREVIATED COMPONENT MAINTENANCE MANUAL
C406-1 (453-5002), C406-1HM (453-5003)
Upon activation, the LED will display a long single flash, which is normal. Any self-
test error codes will display following this initial flash. Do not confuse the initial flash
with a 1-flash error code. If there are multiple errors, there is a 0.5 to 1.0 second
pause between each error code.
PROBABLE CAUSE
Indicates a G-switch loop open (Pins 5 and 8)
disconnected at ELT
connector at ELT end)
Indicates a 406 MHz transmission problem
output or coax cable
Antenna or installation faulty
Insufficient ground plane
antenna causing re-radiation
POSSIBLE SOLUTION
Check connector and tighten as necessary
Check condition of connector pins and
repair or replace as necessary
Repair open jumper
Verify the coax cable/antenna is
connected and in good condition
Perform continuity check of center
conductor and shield
Check for a shorted cable
Check for intermittent connection in the
coax cable
Check with a VSWR meter. Check antenna
for opens, shorts, or a resistive ground
plane connection
Lengthen or shorten antenna coax cable
length by 4 to 6 inches
Provide ground plane at least 12 inches in
diameter
Stay at least 10-12 inches away from
upright metal structures
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APR 06/10