No Sync Signal Jrc Radar < Latest | 2025 >

The Signal/Control (SigCon) cable between the scanner and display carries the sync. If moisture wicks into the BNC or N-type connectors, the impedance changes, attenuating the 1-5V sync pulse to 0V.

The "No Sync Signal" error on a JRC radar is intimidating, but it is a logical, traceable fault. In 9 out of 10 cases, it is a cabling issue (corrosion or broken conductor) or a failing azimuth sensor. However, the remaining cases require oscilloscope analysis and knowledge of JRC’s unique interface board architecture.

Your immediate action plan:

Marine electronics are unforgiving, but disciplined troubleshooting saves your vessel from a dark radar screen when fog closes in. For JRC radars, respect the sync signal – without it, you are navigating blind.

---

Need professional support?
Contact JRC technical support (Tokyo or regional offices) with your radar model number and firmware version. They maintain service bulletins specific to "No Sync Signal" for each legacy model. Alternatively, consult a certified JRC marine electronics technician – and provide them with oscilloscope screenshots from your troubleshooting.

This article is for informational purposes. Always refer to the official JRC service manual for your specific radar model (JMA-6100/7100/9100/9170/NXT/NX series) before performing repairs.

No Sync Signal " alert on a JRC (Japan Radio Co.) radar system is a critical status message indicating that the display unit has lost its timing pulse from the transceiver. Without this synchronization, the radar cannot accurately time the "flight" of radio waves, rendering it unable to calculate distances or bearings to targets. Common Causes & Troubleshooting

When this error appears, it typically points to one of the following hardware or communication failures: Scanner/Transceiver Issues

: If the scanner fails to rotate or transmit, the synchronization pulse is never generated. This can be caused by motor failure, relay circuit issues, or a faulty transmitter/receiver control circuit. Wiring and Connectivity

: A common culprit is a damaged or loose installation cable. Specifically, the wires carrying the trigger (timing) signal or the azimuth (bearing) information may be compromised. Power Supply Instability no sync signal jrc radar

: Marine radars require stable voltage to operate the magnetron and turning mechanism. Insufficient power can cause the transceiver to drop the sync signal intermittently. Processor Glitches

: In some cases, a software "hang" in the radar processor can trigger false alerts. A common first step is to switch the unit OFF and ON again to reset the processor. What the Sync Signal Does synchronizer serves as the "heartbeat" of the radar system. It provides: Trigger Pulses

: It tells the transmitter exactly when to fire a burst of energy. Timing Reference

: It starts the timer for the receiver to listen for echoes. Display Alignment

: It ensures that the "blips" you see on the screen are placed at the correct distance and angle. Safety and Regulations Operating without a functional radar can be a violation of SOLAS (Safety of Life at Sea)

regulations, especially for vessels over 3000 GT which are required to maintain active 9 GHz (X-band) and 3 GHz (S-band) systems for collision avoidance.

Troubleshooting the "No Sync Signal" Error on JRC Radars The "No Sync Signal" error (often appearing as "TXRX(AZI) Error" on newer models) is a common hurdle for mariners using JRC Marine Radar systems. This error indicates that the display unit is not receiving critical timing or rotation data from the scanner, effectively "blinding" your navigation. Immediate Causes & Quick Fixes

When this signal is lost, your radar cannot determine where the bow is or how far the antenna has rotated. Use these steps to identify the culprit: JRC Radar TXRX(AZI) Troubleshooting Guide | PDF - Scribd

Important Safety Warning:
Radar transceivers use high-voltage components (Magnetron, Modulator). Only qualified marine electronics technicians should perform internal repairs. This guide focuses on troubleshooting external and configurable causes. The Signal/Control (SigCon) cable between the scanner and

---

Through decades of service bulletins and field experience, the "No Sync Signal" error on JRC radars typically falls into five categories:

Radar sync errors are often preventable. Follow this JRC-recommended PM (Preventive Maintenance) schedule:

Quarterly:

Annually:

---

---

Final Note: A “no sync signal” fault on a JRC radar is most often a cabling issue or a scanner PCB trigger circuit failure. Always start with the cable – 60% of cases are solved there. If the antenna rotates freely but no sync, the trigger generator inside the scanner is the prime suspect.

A "No Sync" signal on a JRC (Japan Radio Co.) radar typically indicates a communication failure between the scanner (antenna) and the processor unit. This error prevents the radar from properly synchronizing the received pulses with the display, resulting in no image or a distorted visualization. Common Causes

Physical Connections: Loose or corroded pins in the multi-core cable connecting the antenna to the display unit.

Rotation Signal Failure: The scanner motor may not be rotating, or the encoder (azimuth signal generator) is failing to send rotational data back to the processor.

Power Supply Issues: Insufficient voltage reaching the scanner unit can cause the synchronization logic to fail.

PCB Malfunction: A failure in the radar interface circuit or the signal processing board (often the "TRX" or "Control" board). Troubleshooting Steps

Check Power & Motor: Verify if the antenna is physically rotating. If it isn't, the issue is likely the motor, relay circuit, or power supply. Need professional support

Inspect Cables: Power down the system and check the equipment cable and end processing. Look for moisture or damage in the terminal strips inside the scanner unit.

Run Self-Diagnostics: Use the "Test" tab in the maintenance menu (often accessible by holding the left button on "Main Menu" and entering password "0") to check for specific error codes like "TXRX(AZI) Error".

Verify Magnetron Status: Ensure the magnetron is within its operational life (typically <4,000 hours). You can check the current in the "Test" tab; it should generally be between 5.0 and 9.5.

Reset Interface: In some cases, a system reset or reseating the radar interface cards can restore communication.

For further technical support, refer to the JRC Service Network or specific model manuals like the JMA-5200 series service guide. ECDIS:JAN-9201/7201｜JRC（Japan Radio Co.,Ltd.）

Title: Troubleshooting "No Sync Signal" on JRC Radars: Causes and Solutions

A "No Sync Signal" error on a JRC radar indicates a break in communication between the antenna scanner (the rotating unit outside) and the display processor (the screen inside). Without this signal, the radar cannot determine the antenna's angular position, resulting in a blank or stationary screen and an inability to generate a map.

Here is a helpful guide on diagnosing and resolving this issue.

---