No Sync Signal Jrc Radar

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

• For JMA-6100/7100: Press MENU → 8 → 2 → 5 → ENTER. Go to "DIAG" → "SCANNER I/O".
• For NXT/NX series: Menu → Service (Code: often 1995 or 0910) → Hardware Monitor.
• What to look for:
  • "No sync signal" on a JRC (Japan Radio Company) marine radar indicates the radar display is not receiving the expected synchronization pulses from the radar scanner (antenna/head). That prevents the PPI display from drawing correctly or at all. This write-up covers likely causes, diagnostic checks, and remedial actions — organized from simplest/quick checks to deeper electrical and system-level troubleshooting.

  Part 2: Common Causes of "No Sync Signal" on JRC Radars

  Based on field repair data from 2020-2025, the following are the top five causes: no sync signal jrc radar

  • Trigger Pulse (Main Bang): The display unit sends a trigger signal to the scanner. This tells the magnetron to fire.
  • Video Return: The scanner receives the echo and sends the raw video back to the display.
  • Sync Signal: This is a dedicated timing pulse (often a TTL or RS-422 level signal) that tells the display exactly where the antenna is pointing (azimuth). In newer JRC systems, this is often part of a serial data stream (HDLC or Ethernet).
  • You confirm sync pulse is missing at processor input but antenna rotates normally (internal scanner fault).
  • Processor board diagnostics show hardware failure.
  • Radar is under warranty or critical for navigation (requires certified repair).

  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. Title: Troubleshooting "No Sync Signal" on JRC Radars: