1834C radar suddenly stopped displaying targets revisited

[SailorLinda]

I originally posted this topic on April 22 2025 (please refer to that thread so I do not have to re-write everything) and we are still having issues. After some back and forth with Johnny Electron at Furuno we decided to purchase a new-to- us radar dome which was expected to arrive in May 2025. For various reasons it did not get delivered so during the summer cruising season of 2025 we had no radar but the chart plotter display of our ancient 1834C continued to work flawlessly.
In January 2026 I ordered another radar from a dealer in the USA and they assured me the radar is a functional unit, they sent me screen shots of the display. It is exactly the same radar as the one we had originally. It finally arrived mid-February 2026 and last week we installed it on our boat. The display screen does not show us any targets, just like our original radar - the one that failed (maybe it did not fail?). We contacted the dealer and the technician suggested performing a radar optimization and if that did not work then perform a reset to factory default. We did both and there are still no targets displayed. Since the dealer tells me that the radar we bought works we now think that our RDP-149 display is not working properly. Is this a modulator board issue as was suggested in the original thread of April 2025? I do not know where the modulator board is located. As I said the chart plotter display works - could just the radar part of the display fail?
Thank you for any help you can give me.
SailorLinda

 

[SilverKing]

SailorLinda,

Quick question/something to check. On the 1834C/VX2, is the Monitor Mode turned On or Off?

Access to this function - Hold Menu while you power up the unit>continue to hold menu until you get the blue screen>select Installation Mode>Menu>System Configuration>Installation Set-Up>Radar Set-Up

The modulator is in the radar itself.

 

[SailorLinda]

The monitor mode is set to off.

 

[SailorLinda]

As I mentioned in the original question the chart plotter display works perfectly - could just the radar part of the display fail?

 

[Johnny Electron]

There could be an issue with the radar processing part of the SPU board. Being that you are reporting the same issue with two different radar scanners it greatly increases those odds. After connected the radar did you take the boat away from built up area and run the RADAR OPTIMIZATION? That is a very important part of having the radar setup its levels. It isn't something to do inside or next to buildings.

 

[SailorLinda]

Thank you for continuing to respond to my questions on what is now a legacy Furuno installation.

Yes, we did do a radar optimization.

As I wrote in a previous entry we, and our boat, are now close to the end of our sailing expiry date and we do not want to purchase brand new instrumentation which is why we bought the new-to-us radar dome. However now it seems like there may be a problem with the display and I am assuming that the SPU board is in the RDP-149 display.

Prior to my trying to find, and purchasing, a used RDP-149 display, I really would like to know: Is it possible for just the radar processing part of the SPU board to fail? The chart plotter display still functions correctly. I am trying to work my brain around how the radar could fail so dramatically and the chart display still function as it should.