A "No Sync Signal" error on a JRC radar generally indicates a breakdown in communication between the display unit (processor) and the scanner unit (transceiver). This synchronization signal is critical for timing the radar pulses and mapping the returns accurately on the screen. Core Causes of Sync Signal Failure Hardware Malfunction in Scanner:
Motor/Rotation Issues: If the radar antenna is not physically rotating, the scanner cannot generate the synchronization pulses (such as azimuth pulses) required by the processor.
Encoder Failure: The encoder within the scanner unit, which tracks antenna position, may be faulty or disconnected. Inter-Unit Connectivity:
Cable Damage: The multi-core cable connecting the radome/scanner to the display unit is the most common point of failure, often due to corrosion at the terminal strip or physical shielding damage.
Poor Connections: Verify that all terminal pins (e.g., Scanner TB101 or Processor TB4101) are securely seated and free of oxidation. Power Supply Instability:
Insufficient voltage can cause the transceiver to fail during transmission, even if the display stays on.
A faulty power supply board (e.g., CBD-1661) can prevent the scanner from outputting the necessary rotation signals. Troubleshooting Procedures
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
: 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 no sync signal jrc radar
: 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.
| Check | Action | |-------|--------| | Antenna Rotation | Listen for the antenna rotating. If stopped, check the scanner motor and power. | | Cable Connections | Ensure the main interconnect cable is fully seated and undamaged at both the display and scanner. | | Power Cycle | Turn radar off for 30 seconds, then restart. A transient glitch may clear. | | TX Status | Confirm the radar is in Transmit mode (not Standby). |
Modern JRC radars allow you to set rotation speed (24, 36, 48 RPM) via software. If the scanner is physically rotating at 24 RPM but the display is set to SCAN SPEED: 48 RPM, the sync timing will be rejected as invalid, triggering the alarm.
0.5 mm to 1.0 mm between sensor and gear is critical. Use a non-magnetic feeler gauge.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.
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 A "No Sync Signal" error on a JRC
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.
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.）
Introduction
JRC (Japan Radio Company) radar systems are widely used in various maritime and aviation applications for navigation, surveillance, and tracking. One of the critical components of a JRC radar system is the synchronization (sync) signal, which ensures that the radar's transmitter, receiver, and display systems are properly coordinated. However, in some cases, a "No Sync Signal" error may occur, which can lead to malfunctioning of the radar system. This essay aims to discuss the concept of a "No Sync Signal" error in JRC radar systems, its causes, effects, and possible solutions. Field-Fix Attempts
What is a Sync Signal in JRC Radar?
In a JRC radar system, the sync signal is a timing signal that synchronizes the transmitter, receiver, and display systems. It ensures that the radar's transmitter sends out pulses at precise intervals, and the receiver is ready to receive the echoes at the same intervals. The sync signal is generated by the radar's master timer and is distributed to all subsystems. The sync signal is essential for proper radar operation, as it prevents errors in range and bearing measurements.
Causes of No Sync Signal Error
A "No Sync Signal" error in a JRC radar system can occur due to various reasons, including:
Effects of No Sync Signal Error
When a "No Sync Signal" error occurs in a JRC radar system, it can lead to:
Solutions to No Sync Signal Error
To resolve a "No Sync Signal" error in a JRC radar system, the following steps can be taken:
Conclusion
In conclusion, a "No Sync Signal" error in a JRC radar system can have significant consequences on radar operation, leading to inaccurate measurements, loss of target tracking, and system instability. Understanding the causes and effects of this error is essential for effective troubleshooting and maintenance. By identifying and addressing the root cause of the error, radar operators can ensure reliable and accurate operation of their JRC radar systems.
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