Sunday, 8 April 2012

B&G Network VHF fix

Well it will work for some, in my case it did not. Searching for info on the old B&G Network VHF I have I found a cruisers forum There I found a mail telling me that the same set was also branded as a Kenyon RT80 or a Vigil RT80.
I have contacted B&G USA about the set, their reply was they had no circuit diagrams for the set.

My set has a decent digital readout, all functions work, except there is no audio either way, plus the mike does not work either. I decided to sign up to the forum so that I could discuss the issue with who ever posted the info, I had an email back from the USA that same afternoon!

With the four screws holding the front panel removed its easy to see the memory battery. I will next remove that pcb and find out why the light does not work?

The view inside the space between the pcb panels, I see nothing loose or burnt.

The entire set is quite easy to work on and opens out quite well.

To replace that 3 volt memory battery should be easy, its quite dead now.

The LCD and its related push buttons.The light source is the four white rectangles between the buttons, they seem not to work?

Mail from the forum member, Martin follows.

Hey Roy,

Yeah.... these were kind of weird radios, even for their day. The reason I loved it was that it fit into my instrument console so well at the helm of my Morgan 41 center cockpit sloop. I still have another one that a friend of mine gave me that also wasn't working. Same problem as my original one, and an easy fix. However, before we get into the "fix" I decided not to install this one in my new Freedom 32. For $100 US I just bought the RAM3 remote VHF microphone to go with my Standard Horizon VHF. It was less money, less labor to install, and the extra external speaker is not required, as it's a speaker AND a microphone all in one. The RAM3 also gives me WAY more functionality at the helm. So...if you get into the B&G VHF and it's not working out, or can't be repaired, I wouldn't spend any money on it. I'd suggest just going the remote mic route and I think you'll be much happier.

There is a small memory battery to the right of the picture, this one is dead.

See attached for the manual, and now for the fix. You need to take the entire case apart. It's a little tough to get apart as I recall, but once you slide the unit away from the back you will be able to get to the circuit board. The fix is easy. It's about a bad ground connection inside. There are screws that mount the circuit board and there is one MAIN screw (as I recall---from over 15 years ago!) and this main screw is the culprit. I believe there was a ground wire that went from it to the case? Not any rate if you unloosen ALL the screws that physically mount the circuit board and clean up any corrosion under these screws, then screw them back down tight that is all there is to it. The dead functions of the radio are simply because there is no return to ground for the negative side of the power supply when those screws get electrolysis and corrosion under them.

There are actually two circuit boards.

Hope this helps. After I fixed mine it worked flawlessly for the next ten years and was working fine when I sold the boat back in 1999.


Great service from the forum and its members.

click on the picture for a larger view.

Progress of sorts, I can see that this Toshiba amplifier has been popped, it controls audio and thats what my B& Network VHF lacks. I have located a new one and may have it tommorrow. I now need a solder sucker and my trusty 12 volt soldering iron, its a 16 watt output so should do the job.

A new Toshiba amplifier I found it locally for R15, thats about U$2.00 give or take a few cents, now to fit it!
Notty in the UK has advised I cut the seven (7) pins as close to the unit as posible, then unsolder the pins one by one, then with the solder sucker, remove the excess solder. I may have to use a small drill bit to open each hole?

On the VHF circuit board, positive (+) is upwards.

I have raised the round battery off the small plastic sheet it was glued to, next I will clip it free with nail clippers, that will leave me with two prongs I can solder to.

A selection of suitable batteries, I need just the one and will have to pre solder a wire to the positive and negative side of the new battery.

The memory battery will then be next, will this work? I have no idea!


A progress report:

July 17th 2013, I had a local technition install the Toshiba part for me, those seven prongs look like messy job to me?

The radio now lights up, receives very well, the audio is good and it scans and does all of what we expect it to do, excepting there is no transmission when the mic button is pressed. As the up and down buttons do nothing either, its possible that the mic is faulty? The set will go back to the tech guy tomorrow.