Garmin GRA 55 Maintenance Manual - Page 32

Fault Type Fault Name Suspended Power Fail DDS TX PLL Lock LO PLL Lock Radio HW Auto RF Self-Test Main RF Self-Test Description Cause Internal power supply failure Aircraft power lost for greater than 220 ms Aircraft power failure Failure to program DDS or read back correct register information from the DDS Internal communication error The TX PLL is not locked while the Internal failure unit is transmitting. The LO PLL is not locked while the Internal failure unit is transmitting The self-test signal is not within the acceptable frequency range Improper antenna connections Internal failure Improper antenna connections The self-test signal is not within the acceptable frequency range Internal Failure Resolution Check aircraft power supply. Cycle power to unit. Return power to unit. Note there are no assert log entries for this fault. Cycle power to unit. If fault persists, return unit to Garmin for service. If fault persists, download the assert log and send to Garmin for diagnosis. If fault persists, download the assert log and send to Garmin for diagnosis. Check antenna installation and all cable connections. If fault persists, download the assert log and send to Garmin for diagnosis. Check antenna installation and all cable connections. Download the assert log and send to Garmin for diagnosis. If fault persists, return unit to Garmin for service. 190-01277-A3 Rev. 1 System Maintenance Manual GRA 55/5500 Bell 206 STC Page 5-6