Garmin 400W Series Instructions Manual page 15

Problem
The 400W Series unit
does not transmit.
The sidetone level is
too low or too high.
OBS Resolver won't
calibrate.
OBS indication on
400W Series unit
does not agree with
OBS setting.
400W Series unit is
not receiving heading
from compass system
(ARINC 429 heading
input used)
RMI pointer does not
indicate correctly
Tuning data not
updating DME
ARINC 429 device is
not receiving data
from the
400W/420W/430W.
400W Series
Instructions for Continued Airworthiness Bell 407
Possible Cause
 The PTT input is not being pulled
low.
 No transmit power to the COM.
 The input voltage is too low.
 Wrong type of headsets, or level
needs adjustment.
 Incompatible resolver or improper
connection.
 400W Series unit resolver input not
calibrated correctly.
 Resolver has not been calibrated.
 ARINC 429 input port speed not
correct
 Wiring connections are incorrect.
 Desired RMI source has not been
selected.
 Wiring connections are incorrect.
 Incorrect configuration.
 Wiring connections are incorrect.
 400W Series unit ARINC 429
output not configured correctly.
 ARINC 429 input port speed not
correct
 Wiring connections are incorrect.
Solution

Check that the PTT (mic key) input is
pulled low for transmit.

Make sure power input is connected to
the COM 25-pin connector P4002 11
and 12 and ground to P4002 21 and 22.

Increase input supply voltage to
>12VDC. (>24VDC for 430AW models)

If necessary, adjust the sidetone level.
Sidetone adjustment is found on the
COM Setup page.

Check the resolver specifications and
wiring.

Check wiring and calibration.

Check ARINC 429 input port speed
setting for port that device is connected
to and verify that the speed is correct for
that device.

Check wiring.

Check the OBI source selection on the
Main CDI/OBS Config page.

Check wiring.

Check the DME Channel Mode on the
VOR/LOC/GS CDI page.

Check wiring.

Check ARINC 429 output port setting for
port that device is connected to.

Check ARINC 429 input port speed
setting for port that device is connected
to and verify that the speed is correct for
that device.

Check wiring.
190-01226-14 Rev. 3
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