Gsu 75B/Gdc 7400 Troubleshooting - Garmin G1000 Nxi System Maintenance Manual

7. The operator should carry out the actions called for in the prepared test sequence.
It is important that all actions are carried out in the order and at the precise
elapsed time as specified in the prepared test sequence.
8. When the operator has completed the actions specified in the test sequence, press the
ENTER button to indicate that the process is complete. When this is done, the TEST
COMPLETE field stops blinking.
9. PFD1 informs the operator if the installation has passed or failed the magnetometer
interference test. If the test passes, no further action is required for this test.
If the test fails, the installation should be considered unreliable until the source of
magnetic interference is identified and remedied. When the magnetometer interference
test fails, record the three magnetometer maximum deviation values and their
corresponding timestamps. Reference the appropriate installation manual for the GSU
75B (190-01639-00), GRS 77 (190-00303-10), and GRS 7800 (190-01091-00) for
acceptable magnetic interference limits. Compare the corresponding timestamps with
the prepared test sequence to identify which action produced the problem. Contact
Garmin for assistance in resolving the problem.
Three common reasons for a failed magnetometer interference test are: 1)
rudder bellcrank or other structure has become magnetized, 2) new
equipment is installed in close proximity to the GMU 44 magnetometer, and
3) an existing or new electronic device has become grounded through the
aircraft structure instead of via the proper ground wire in a twisted shielded
pair.
10. Press the ENT key on the PFD to conclude this procedure.

GSU 75B/GDC 7400 Troubleshooting

Air Data Symptoms
Symptom
Altitude shown on PFD is different
than standby altimeter
G1000 NXi System Maintenance Manual
King Air 300 Series
190-00716-N1
NOTE
NOTE
Recommended Action
•
Perform a pitot/static leak and accuracy check.
•
Determine which instrument is outside limits and replace.
Note: The GSU 75B and GDC 7400 software/configuration for the 300
Series contains error correction at 19,000 feet and above. The
standby altimeter does not contain any correction.
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