190-01007-A1 System Maintenance Manual GTN 6XX/7XX Part 23 AML STCRev. 6 Page 5-195.4 GMA 35 TroubleshootingThis section provides information to assist troubleshooting if problems occur after completingmaintenance. Refer to the system configuration log retained in the aircraft permanent records for a list ofinterfaced equipment and system configuration data.Table 5-13. GMA 35 TroubleshootingProblem Possible Cause Corrective ActionAudio volume, audio routing,music, marker beacon status,or intercom are not workingproperly.GMA 35 is not configured properly.Check the configurationagainst the configuration log toensure that the GMA 35 isconfigured properly.Audio panel operates only infailsafe mode (pilot headsetconnected to one COM radio,red X over the audio panelcontrol field).GMA 35 is disconnected from aircraftpower or ground.Ensure power is connected toP3502, pins 8 and 9, andground is connected to P3502,pins 10 and 11. Check circuitbreakers and avionics switch.GMA 35 is not seated correctly.Verify that the GMA 35 is fullyseated. Verify that counter-sunk flathead screws are usedto secure the GMA 35connectors to the backplate.RS-232 communication between theGTN 7XX and the GMA 35 is notfunctioning correctly.Check for proper configurationof the GTN and GMA 35RS-232 ports.Check for correct wiringbetween the audio panel andthe GTN 7XX.
