Electrical gremlins with the radio

gotchiguy · 25 October 2010, 18:55

Having had a good few issues with our Raymarine RAY 240E, we finally thought that having fitted our repaired units today that we would at last have a functioning fixed radio.

For a sort of dummy-run, I put the box into the console and plugged everything in without screwing it in: although the repaired handset didn't work quite as it should, the brand new one from the second set we have acquired appeared to function perfectly, even retaining our MMSI when switched on and then off again

!

Having screwed the box back into the fibreglass, I plugged everything back in: appears to work fine, turns on, receives well, still contains MMSI......however....whenever you transmit or just blip the transmit button, the trim tabs turn on! The LEDs on the display do their little warm up thing, and then the closing thing - when the power is cut they normally retract to the raised state -, and even though the tabs are already fully raised the motors whirr for a second or so...very weird. Doesn't appear to do it when their down or even just switched on already but its strange when they do.

Our only two thoughts so far are that something is making an electromagnetic field collapse within the radio when the button is pressed and somehow this causes an issue with the tabs...or... alternatively, when the radio transmits it causes such a drain of current on the battery that the tabs are tricked into thinking that the power has been cut, although it wasn't even on in the first place, and the switch remained off continuously. Bearing in mind that we haven't tested it with a running engine yet, it doesn't seem quite right!

Although I'm doing a GCSE in electronics at the moment, my skills do not go much further than tracing the wires to their origins as I have done, the only interesting end enters a wrap of insulating tape and then emerges as a big thick cable plugged directly into the tabs box in the console. The only places anything related to the radio or tabs meet is at the isolation switch, and the handset cable is cable tied to one of the tab wires at a certain point, although both are heavily insulated.

Any thoughts would be much appreciated, in the short term, leaving the tabs "on" even when not in use would seem the logical option, although most of the time they are left down to a certain extent so not a problem.

Puzzzling!

Erin · 25 October 2010, 19:26

I've no idea what your problem may be, but there's a couple of things you could consider, in an attempt to narrow down the fault.

Does it make any difference whether you are on high or low power for transmit? Does the radio actually transmit ok?

Are you able to temporarily power the radio up with a separate battery (to isolate it from the boat's wiring) to see if it still does it. If it does, then it suggests the problem is EMF interference based.

I'm assuming you haven't bent any pins on connectors or mis-wired the replacement.

Cookee · 26 October 2010, 07:53

If I was a betting man I would say you have some serious wiring issues on that boat!

Channel Ribs · 26 October 2010, 08:19

Quote:

Originally Posted by Cookee

If I was a betting man I would say you have some serious wiring issues on that boat!

Having looked at the original problem and been unable to get the fault to reproduce with anything resembling consistency I am inclined to agree!

Keith's suggestion of a separate power supply for testing the vhf is an excellent one.

Gotchidad · 26 October 2010, 08:41

Hi Martin,

We've made a bit of progress since you saw the boat. Raymarine found problems with both the handset and the main radio box which have been repaired. The radio now seems to work fine save for this strange interference. It's not as if the wiring is difficult to follow so I can't think what's happening.

David

Erin · 26 October 2010, 09:16

I think I'd make sure the negative (ground) cables are well secured and making good contact. A quick test with a mutimeter would be ideal. Marine wiring problems are invariably 'ground' related.

Channel Ribs · 26 October 2010, 09:25

Quote:

Originally Posted by Erin

Marine wiring problems are invariably 'ground' related.

A bold statement, but I am not going to disagree.

Jizm · 26 October 2010, 11:34

Are they the Lenco trim tabs, with the seperate signal wire for power?

Anchorhandler · 26 October 2010, 12:01

Hi
To give you an idea nowadays at just how sensitive modern electronics can be to RF interference, a few years back we suffered a problem on a 38000hp fast cat ferry (the ones which go back and forward to the Channel islands). We suffered repeated shut downs of one of the main engines during passages across the channel. The shut down would happen at random times but always concern the aft wo engines.

It took months to find the problem which turned out to be.................................passangers standing out on the lower aft deck using their mobile phones which in turn interfered with the electronic 'fly-by-wire' engine governors.

i'm not saying that this is your problem but as someone already suggested try transmitting on 1w then unplug the antenna completely and re-try.

Failing this, the only other output found on a 'leisure' VHF is an external speaker, do you have one in use? if so check the integrity of the cables.

Otherwise i would (as again,already suggested) temporarily run a dedicated fused supply and negative direct to battery to avoid any internal earth issues in the VHF itself.

Hope this helps.....oh and good luck

Simon

Erin · 26 October 2010, 15:40

Quote:

Originally Posted by Anchorhandler

i'm not saying that this is your problem but as someone already suggested try transmitting on 1w then unplug the antenna completely and re-try.

I'd be extremely wary abouyt trying to transmit without an aerial attached. You could do a lot more damage than good. It certainly advises strongly against doing such a thing on my Icom. It may solve your interference problem though, cos it'll burn out the radio

Anchorhandler · 26 October 2010, 16:20

Quote:

Originally Posted by Erin

I'd be extremely wary abouyt trying to transmit without an aerial attached. You could do a lot more damage than good. It certainly advises strongly against doing such a thing on my Icom. It may solve your interference problem though, cos it'll burn out the radio

Hi Erin
Quite right.....although harshly put....
Most modern sets will throttle back the transmit power should an antenna miss-match occur or the antenna suffers damage (mast top antenna's in rough weather etc...)
But you are right though, I should have warned not to engage in a full blown conversation but just 'click' the trasnmit button to see if the problem persists.
Thanks for picking this up....

Simon

Chris · 26 October 2010, 20:24

I would say your idea of the power drain fooling the tabs into thinking they are being turned off is a good one.

I would be looking at the switched B+ on the tabs and taking a seperate feed to it directly from the battery and seeing if the problem still occurs.

I would also look at your isolator switch and bypass that.

The lenco installation manual is on their website.

Erin · 27 October 2010, 15:09

Quote:

Originally Posted by Anchorhandler

Thanks for picking this up....

Simon

Pas de probleme

gotchiguy · 27 October 2010, 18:26

Well, it looks as if THIS problem has cured itself

, worked flawlessly yesterday and appeared to work flawlessly today until I noticed that there was a message at the base of the radio which read "release PTT now!". Investigating further it appeared that it was transmitting continuously on channel 16

. Since we hadn't touched it since leaving port, and no button was in the slightest being pressed, we fiddled about with it for a few seconds before concluding that we had to unplug it, which we quickly did to stop the transmission. Plugging it back in port, it only turns on to read "unable to connect to base unit". Similar to the problems we had in the past and that Martin tried to troubleshoot in the summer

. I suppose it just goes to prove how temperamental we know that it is, seeing that I would bet that it will work flawlessly when fired up tomorrow

. If not, we'll swap in our other handset

and see how it goes

Erin · 27 October 2010, 18:39

Quote:

Originally Posted by gotchiguy

Investigating further it appeared that it was transmitting continuously on channel 16

.

That's a bit alarming

. I think you either need strong words with Raymarine or to fit a different model or make of radio.

gotchiguy · 27 October 2010, 18:56

Quote:

Originally Posted by Erin

fit a different model or make of radio.

I think that's the way the man in charge is heading, tbh he was already heading in that direction - getting them repaired was the final time he was prepared to give them time of day. He reckons a normal icom or Garmin will be the way forward

...only thing would be how to fit them, obviously not to hard to do it ourselves, but finding a way to cover the holes for the old one or even just moving it to a less convenient place as a "backup"

might be tricky. Our only thoughts so far on the cause of this latest malfunction related to the centimetre depth of water which has found its way into what was a bone dry console yesterday

martini · 27 October 2010, 19:15

I'll shortly have a Garmin VHF 300ais for sale, expensive bit of kit but I'll do you a very good deal if you're interested

Gotchidad · 27 October 2010, 20:39

Thanks for the thought, Matt, but to be honest, I'm so fed up with the Raymarine that I'm thinking of getting a really basic VHF and not bothering with any of the fancy features. The Garmin does look a nice bit of kit though. David

boristhebold · 27 October 2010, 21:25

I reckon you have a short somewhere withe wiring, you know what you have to do...... Check over all the wiring with a circuit tester. It's prop ably worth it.

martini · 27 October 2010, 22:12

Quote:

Originally Posted by Gotchidad

Thanks for the thought, Matt, but to be honest, I'm so fed up with the Raymarine that I'm thinking of getting a really basic VHF and not bothering with any of the fancy features. The Garmin does look a nice bit of kit though. David

Make sure its an Icom then

Of the thousands of pounds worth of electronics I've worked my way through on various boats over the years, I've never had a single issue with any Icom