To Next PageTo Next PageHow to fix a Garmin GNC 355 GPS/GNX/GNC that does not power on?
To resolve the issue of your Garmin GPS 175, GNX 375, or GNC 355 not powering on, begin by checking the circuit breakers and the main avionics switch. Ensure that power is correctly connected to the main 62-pin connector (P1751, P3751 or P3551) at pins 21 and 42, and that the ground is connected to pins 20 and 41.
What to do if my Garmin GNC 355 GPS/GNX/GNC does not compute position?
If your Garmin GPS 175, GNX 375, or GNC 355 is not computing its position, the issue might be due to inadequate GPS signals. Check the GPS antenna connections to ensure they are secure. Also, make sure the aircraft is in a location free from obstructions such as hangars, buildings, or trees.
Why does Garmin GNC 355/GNX/GNC signal drop when avionics are turned on?
If the GPS signal level of your Garmin GPS 175, GNX 375, or GNC 355 drops when avionics are turned on, it's likely due to noise interference from other avionics. To address this, turn off all other avionics and then turn them back on one at a time to identify the source of the interference. Reroute the GPS cable and reposition the GPS antenna away from the interfering unit.
Why are Garmin GNC 355 GPS signal levels very low?
If the GPS signal levels on your Garmin GNC 355 are very low, this could be due to several reasons. First, check the GPS antenna installation, connections, and cable routing, ensuring the antenna is mounted on top of the aircraft. Second, ensure the aircraft is clear of obstructions like hangars, buildings, or trees. Third, RF interference at 1575.42 MHz from VHF COM can be the cause. Add a 1575.42 MHz notch filter in COM coaxial. Fix or replace the COM. Disconnect the ELT antenna coaxial to check for possible re-radiation. Move GPS antenna further from the COM antenna.
Why are Garmin GNC 355 GPS 175 GPS signal levels very low?
If the GPS signal levels on your Garmin GPS 175 are very low, it could be due to improper antenna installation or the antenna being shaded. Check the GPS antenna installation, connections, and cable routing, ensuring the GPS antenna is mounted on the top of the aircraft. Also, make sure the aircraft is clear of obstructions like hangars, buildings, or trees.
Why are Garmin GNX 375 GPS signal levels very low?
If the GPS signal levels on your Garmin GNX 375 are very low, it could be due to improper antenna installation or the antenna being shaded. Check the GPS antenna installation, connections, and cable routing, ensuring the GPS antenna is mounted on the top of the aircraft. Also, make sure the aircraft is clear of obstructions like hangars, buildings, or trees.
Why doesn't OBS indication on Garmin GNC 355 GPS 175 agree with OBS setting?
If the OBS indication on your Garmin GPS 175 does not agree with the OBS setting, the OBS resolver input may not be calibrated or may be calibrated incorrectly. Check the wiring and calibration to resolve this issue.
Why doesn't OBS indication on Garmin GNX 375 agree with OBS setting?
If the OBS indication on your Garmin GNX 375 does not agree with the OBS setting, it's possible that the OBS resolver input is either not calibrated or has been calibrated incorrectly. To fix this, check the wiring and calibration of the resolver input.
Why doesn't OBS indication on Garmin GNC 355 agree with OBS setting?
If the OBS indication on your Garmin GNC 355 does not agree with the OBS setting, the OBS resolver input might not be calibrated or could be calibrated incorrectly. You should check the wiring and calibration to correct this.
Why is my Garmin GNC 355 175 not receiving heading from compass system?
If your Garmin GPS 175 is not receiving heading from the compass system (ARINC 429 heading input), it could be due to an incorrect ARINC 429 input speed setting or incorrect wiring connections. Verify the ARINC 429 input port speed setting for the connected device. Also, check the wiring connections; the raw data received by the GPS 175 can be monitored on the ARINC Inputs page found on the Diagnostics page.
General| Channels | 200 |
|---|---|
| Interface | RS-232 |
| GPS Receiver | WAAS |
| Connectivity | Bluetooth |
| Display Type | Color |
| Approaches | LPV/LNAV/VNAV/GPS |
