JRC radar issue - BEARING PULSE ERROR

[diane]

Ok. Not really "Pearson" at all. Problem is on a friend's boat (1975
Hunter).

He's got a JRC 1000 radar unit. It's not worked properly this year
(mast was unstepped over winter).

At first - turned on, appeared to be in order, but there were no
targets on the display - when we could easily several large targets -
like Block Island about 1 mile to starboard. (it was nice clear day,
we were checking the unit out).

Fooled w/ it a bit - thought maybe the problem was at the connection
between the interior wire and the section that runs up the mast.
Jiggled the connection - and the screen went blank.

Got home - had the connector on the mast end of the interior wire
rebuilt. Now - unit turns on, and returns the message "BEARING PULSE
ERROR (BZ)" when we try to put it in XMIT mode.

Anyone got a suggestion ? seen this error before ?

regards...
...diane

[dugout]

Hey Diane;

 

No bearing pulse, or bearing signal error are basically the same thing and it means the radar processor is not getting a keying pulse from the antenna which tells it how to align the target returns. Some radars have bearing signal generator pcb in the antenna. Others have a simple reed switch which gets tripped every rotation, while others have a proximity switch. Upon start up, TX, the processor waits for the keying pulse from the first rotation, to activate the A to D converter and paint the targets on the display. Lack of this pulse will cause the error you are seeing. Anything that keeps the antenna from turning, recording, or reporting the key pulse will cause the error. It could be anything from a loose belt to a main processor, or something in between. My guess in your case would be wiring and the connector but that is a pure WAG. The bearing signal would need to be checked in the antenna and then on the processor. Then it can be traced step by step from one point to the other. It has to be diagnosed on the boat.

 

I hope this helps!

 

Ed
P33-1, S/V "Moriah"
Maryland's Famous Eastern Shore

[Diane C Bonnell]

Ed -

Thanks - we (well, me really, since I'm more technically oriented than he) came to. The hope is that it's a wire issue, and not the radome unit. Fixing (or replacing) the wiring may be a RPITA - but it's still probably less expensive than fixing/replacing the whole deal. Problem really will be determining if the lack of signal is due to bad wiring, or a bad scanner. Not sure how to diagnose that - the wire is a thick bundle which carries both electrical and data signal.

We've got a friend who's an electronics whiz - so there may be dinner, or at least a beverage or two - in his near future.

regards...
...diane

rsvp diane.c...@db.com

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