Garmin G1000 Maintenance Manual page 49

__________________________________________________________________
MFD RS-232
Channel LRU
GCU 476
certain
-CHNL 1
airframes
only
G1000 System Maintenance Manual
190-00907-00
Indicator
MFD/GCU 476 data path is functioning correctly.
MFD/GCU 476 data path is not functioning correctly.
•
Check PFD Alert Window for MFD or GCU
configuration or software error messages. Correct any
errors before proceeding.
•
Verify GCU is powered on by pressing the "ANN TEST"
softkey on the MFD AUX - SYSTEM STATUS page to
see if the key indicators turn on.
•
If GCU will not power on, remove unit and verify power
and ground are present at the GMC connector.
−
If power or ground is not present, troubleshoot
aircraft wiring for faults.
−
If power and ground are present, check the MFD
and GCU connectors for damaged or pushback
pins.
•
Swap PFD and MFD to confirm if the problem is in the
original MFD.
−
Replace original MFD if box turns green after
swapping displays.
•
Replace the GCU 476.
MFD/GCU 476 data path functionality is unknown. Reload
MFD configuration file.
Status
Page 5-13
Rev. B