Garmin GRA 55 Maintenance Manual - Page 28

Fault Type Fault Name PLL Register RF Self-Test POST (Power On Self-Test) Sensor Boot Various [1] Description Cause Resolution After programming, read-back of the PLL register values does not match what was sent from Internal communication error the CPU Cycle power to unit. If fault persists, return unit to Garmin for service. The self-test signal is not within the acceptable frequency range Improper antenna connections Internal failure 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. Sensor processor Internal software not communication successfully loaded error Numerous tests identified in this table are run during Power On Self-Test (POST). Failure of these tests is identified as a Various [1] POST fault during power up and also identified by the fault name in the fault log. Cycle power to unit. If fault persists, return unit to Garmin for service. 190-01277-A3 Rev. 1 System Maintenance Manual GRA 55/5500 Bell 206 STC Page 5-2