Raymarine C120 & 4kw Pathfinder Radar shows only half of the picture

[shorkun]

Was on my way with the radar on, when I got some red lines across my c120, and then vs. seeing all 360-degree radar scans I see only 180 . If I adjust the bearing, then the 180-degree image moves accordingly. The second symptom that started to happen is that when I shut down the radar, it stops in a random position and when I turn it back on, it doesn't start to rotate. I have to manually readjust the antenna and try to turn it on again. It seems that it can start the rotation only if it had stopped at a particular angle, if not, then it won't start spinning again.

Radar passes all tests on the c120 screen, with no failures.
Replaced M92654-S computer with another one, same problem.
Factory settings reset on mfd c120

Please advise

[Sivaa]

Blanking zone for Radar , selected?

Scanner , not rotating? Motor - weak for its torque or connecting pins on Radar Interface / processor - need one time removal & refitting. To be verified .

[shorkun]

Originally Posted by Sivaa

Blanking zone for Radar , selected?

Scanner , not rotating? Motor - weak for its torque or connecting pins on Radar Interface / processor - need one time removal & refitting. To be verified .

Can you clarify in regards to "Blanking zone for Radar" Is there a setting in c120 mfd to limit the scanning zone?

[Sivaa]

Operation manual , on the name of " Sector Blanking " may describe this option . Transmission of Radar unit itself will be avoided in chosen sector blanking area . Total blanking cannot be for 360° and should not exceed 270° or 200° - by adding all options . You may reach through glossary of terms on manual as well . Safety procedure is activated for a reason ! .

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In Radar user manual , I only see guard zone . Not sector blanking . Your observation is as good as no transmission or no reception from specific array groups . If visual observation inside array doesn't get obstructions , you may refer with supplier or technical customer service centre . Warranty terms if available , good . Else , you get guidance . Please update here, as well.
Regards .

[shorkun]

Originally Posted by Sivaa

Operation manual , on the name of " Sector Blanking " may describe this option . Transmission of Radar unit itself will be avoided in chosen sector blanking area . Total blanking cannot be for 360° and should not exceed 270° or 200° - by adding all options . You may reach through glossary of terms on manual as well . Safety procedure is activated for a reason ! .

======================

In Radar user manual , I only see guard zone . Not sector blanking . Your observation is as good as no transmission or no reception from specific array groups . If visual observation inside array doesn't get obstructions , you may refer with supplier or technical customer service centre . Warranty terms if available , good . Else , you get guidance . Please update here, as well.
Regards .

I went through c120 mfd manual and analog 4kw 48inch open array radar installation and user manual, there is nothing that refers to the "blank" zones. The only reference to the zone is in Alarms that set's up monitoring sectors.

I'm thinking of ohm testing the MFD radar connections and cable connected to the radar ohm test next.

[Sivaa]

- according to bearing , image can also rotate ; anywhere in the display . This makes display as good .

- stops in random position ; Park Brake function if available- may verify . Sensitive to start from specific positions - motor cable connection or motor itself . Based on boat's tilting to either direction , unbalanced weight distribution causes than due to specific position of array ?

- 180° shadow region , needs technical support for hardware & software compatibility . Display indicates alike ! .

[shorkun]

Update, I've tested the resistance of the radar cable and MFD.
The radar cable resistance was within 5% range
MFD resistance between pings 6 and 10 was 110 ohm vs 160 ohm According to Raymarine anything, but 160 ohm signifies the failure of the radar circuitry. Procuring a new MFD will keep everyone updated.

[shorkun]

Update...

Got a new c120 Chartplotter, and hooked it up... the same issue.