No Sync Signal Jrc Radar Site

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.

80m coastal tanker, JRC JMA-7132 radar. Symptom: "NO SYNC SIGNAL" appears after 45 minutes of operation. Radar works fine from cold start. Previous technician action: Replaced scanner cable (expensive, did not fix).

: The scanner unit generates a high-power radio frequency pulse through the magnetron.

150m Ro-Ro cargo. Radar: JRC JMA-7322-6. Symptom: Intermittent "No Sync Signal" every 15 minutes, lasting 2 seconds—just enough to lose target tracking. no sync signal jrc radar

Use a digital multimeter to check continuity across the dedicated wire pairs (refer to your specific JRC model's wiring manual for exact pin assignments).

If you want model-specific guidance, provide the JRC radar model number and wiring connection details and I’ll generate pinouts and exact test steps.

Antenna head checks

For technicians: Never trust a multimeter for this diagnosis. You need an oscilloscope to see the pulse. For vessel owners: Budget for a spare SigCon cable and encoder brush kit. For crew: Learn the audible rhythm of your scanner—a change in that rhythm is your early warning before the "No Sync" alarm appears.

Spare parts & likely repairs

This guide breaks down the technical meaning of this error, its common causes, and a step-by-step diagnostic workflow to restore your radar system to full operation. Understanding the Sync Signal The Signal/Control (SigCon) cable between the scanner and

| JRC Series | Common Sync Issue | Likely Fix | |------------|------------------|-------------| | JMA-1000/2000 | Loose internal trigger connector | Reseat J301 on scanner PCB | | JMA-7100 | Corrosion on antenna rotary joint | Replace slip ring assembly | | JMA-5300/5400 | No heading pulse from encoder | Clean optical encoder disk | | JRC 1500/1800 series | Failed trigger transistor (Q12) on modulator board | Replace 2SC4706 transistor |

For models like the JMA-9100 , check if safety switch S101 in the scanner unit is off, as this prevents transmission.

Troubleshooting the "No Sync Signal" Error on JRC Radars Encountering a "No Sync Signal" or related transmission error on a JRC (Japan Radio Co.) marine radar can be a critical issue, especially during navigation in poor visibility. This error typically indicates a communication failure between the display unit and the scanner (antenna), or an internal failure within the transmitter-receiver (TX/RX) circuitry. Understanding the Error Symptom: "NO SYNC SIGNAL" appears after 45 minutes

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