190-01007-01
GTN 725/750 Maintenance Manual
Rev. 5
Page 4-1
4 TROUBLESHOOTING
This section contains LRU-level troubleshooting information for the GTN 725/750. Field troubleshooting
tools are organized into two groups:
•
LRU failure annunciations
•
System messages
Follow the assembly/disassembly procedures in section 5 to remove the GTN unit or component. Follow
instructions in section 1.2 to return the unit or component to Garmin for repair. If the following
troubleshooting approaches are unsuccessful, visit
.
4.1 LRU Failure Annunciations
Invalid LRU data is indicated by a red X over disabled keys and/or grayed out text at the top of the
touchscreen. Figure 4-1 shows invalid LRU data indications for COM, audio panel, transponder, and
NAV functions.
COM
(GTN 750 Only)
AUDIO PANEL
TRANSPONDER
NAV
(GTN 750 Only)
OPERATION
SQUAWK CODE
AND MODE
Figure 4-1 LRU Failure Annunciations
