: If the antenna is not spinning or the rotation signal (Azimuth/AZI) is not reaching the display, the system cannot synchronize the image. Check if the motor is physically rotating.
| | Actual Problem | Verification Test | | :--- | :--- | :--- | | No target echoes but sync error present | Magnetron failed – no trigger, so no sync generated by scanner | Fire an ARPA target. Do you hear magnetron "thump"? No sound = magnetron, not sync. | | "No Sync" only on long ranges (24+ NM) | Low voltage drop on long cable runs | Check scanner supply voltage at the pedestal. Should be +24V ±10%. | | Error appears only when radar is hot | Cracked solder joint on sync transformer | Freeze spray on RD/IF board – error disappears temporarily → reflow solder. |
The ship groaned, banking hard as a wall of black rock materialized out of the fog, missing the hull by less than twenty feet. As the Northern Star
This article serves as a comprehensive guide to diagnosing, troubleshooting, and repairing this common JRC radar fault. What is the "Sync Signal" in a JRC Radar? no sync signal jrc radar
If the antenna fails to rotate, the system may drop all synchronization and trigger a related TXRX(AZI) Error .
A "No Sync Signal" or similar error message on a JRC (Japan Radio Co.) radar display is a critical fault indicating that the display unit is not receiving necessary rotational or timing data from the scanner unit (antenna). This issue often leaves the radar display blank, showing only a "standby" mode, or displaying a consistent error code, rendering the system incapable of detecting targets.
In JRC radar systems, a (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 : If the antenna is not spinning or
If the radar antenna is not physically rotating, the scanner cannot generate the synchronization pulses (such as azimuth pulses) required by the processor.
The problem typically stems from three areas: the motor, the internal circuitry, or the connecting cables. :
: Access the maintenance menu (often requires a password like '0' for service engineer mode) to check internal diagnostic statuses for TX/RX signals. Do you hear magnetron "thump"
Indicates specifically that the Azimuth (heading) signal is missing.
Consult your specific JRC model's wiring diagram (e.g., JMA-5200, JMA-5300, or JMA-9100 series) to locate the pin labeled TRIG , SYNC , or T-SIG .
Go to the mast and look/listen for the scanner turning.