Boat VHF problem

pheran

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The (fairly modern) VHF transceiver on my boat appears to have developed a fault in that while it still transmits, it isn't receiving. This seems to be confirmed, not only by experimenting but also operating the Squelch control doesn't produce the normal loud 'white noise'. No matter where it is positioned, there is just a low volume background hum. When in listening mode, the screen displays RX but doesn't seem to pick anything up. The fact that it can transmit seems to rule out an aerial fault.

So, before I have to drag the set out and send it off some where, does anybody have a bright idea as to what might be wrong please?
 

prv

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I reckon you've tried the obvious things, and it's a genuine fault. If it were mine I might be tempted to open it up and have a look for any visible damage (blown caps, etc), but otherwise I think it needs to see a radio doctor.

Pete
 

rob2

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Just a very long shot... I once failed to fully plug in the extension speaker jack with similar symptoms. Enough to operate the cut out of the internal speaker but not enough t connect the cockpit extension!

Rob
 

dial-a-monkey

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Raymarine Radio? if so it's almost certainly the ceramic filters - that is if you've done the basic troubleshooting and it's not uncovered anything - try using a wire for the antenna - and get someone to call you.

Search this forum and you will find some information about it - some from me - It's not too difficult a repair if you have steady hands, the parts can be hard to source - I got some sent from China took 4 weeks to Croatia - usually LTM450, LM455 or similar.

The Ceramic filters are filters used in the second stage of the radio - the "Intermediate Frequency" of a heterodyne radio. They have a center frequency around 450 or 455Khz. There is a weird sort of corrosion happening in these parts caused by DC bias of the component when it should only have AC passed through it - when you pull one apart you can see the green corrosion on the plates. It seems so common Raymarine should be repairing them without charge.
 
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