In JRC radar systems, a "No Sync Signal" (or similar "No Trigger" or "No Rotation" error) indicates a communication failure between the display unit and the scanner unit. This critical alarm forcibly stops radar transmission to prevent hardware damage. Common Causes & Troubleshooting
Verify Antenna Rotation: Ensure the radar pedestal is receiving the correct voltage. If the motor isn't spinning, the system cannot generate azimuth or heading pulses.
- Open scanner pedestal. Inspect for mouse nests, corrosion, loose terminations.
- Measure sync signal voltage with a multimeter at the display’s rear terminal (look for 2.5–5V AC or DC depending on model).
- Perform a "Heading Alignment" – if the heading marker drifts, the sync processing chip may be failing.
- If the system requires heading input for stabilization and the heading source is absent/faulty, the radar may not display sync — verify gyro/compass/encoder function and cabling.
