VHF Radio problems on a Marlin 300

[Antigua Larry]

I recently picked up our 2012 Marlin 300 after summer layup (we have the boat in Antigua) and I noticed the VHF is not powering on. I had disconnected the handset when it was hauled, and now nothing. All other electronics are fine. There are no signs of corrosion on the connectors. Where is the main radio base located? Any ideas about troubleshooting? I am going to use a meter to determine if power is getting through the connector next.

The wiring diagram I have is worthless - it simply shows the VHF as "not installed by Grady White". Are there fuses somewhere? The diagram refers to another diagram (300-DC-1-1) that does not exist in my manual.

 

[Pat Hurley]

I recently picked up our 2012 Marlin 300 after summer layup (we have the boat in Antigua) and I noticed the VHF is not powering on. I had disconnected the handset when it was hauled, and now nothing. All other electronics are fine. There are no signs of corrosion on the connectors. Where is the main radio base located? Any ideas about troubleshooting? I am going to use a meter to determine if power is getting through the connector next.

The wiring diagram I have is worthless - it simply shows the VHF as "not installed by Grady White". Are there fuses somewhere? The diagram refers to another diagram (300-DC-1-1) that does not exist in my manual.

first check fuses located under the helm, if not there trace back the feed line to the vhf to see if there is an inline fuse

 

[seasick]

What is the brand and model of the unit. I don't fully understand what you mean by "where is the main radio base" located. Usually the the main unit is the one with the dials buttons and screen. Do you have multiple handheld control units?

 

[glacierbaze]

Sounds like a black box unit somewhere, with a ram mike.

 

[Fishtales]

There is a second fuse panel in the overhead radio box. Could have been run up there?

 

[seasick]

Sounds like a black box unit somewhere, with a ram mike.

Could be but a little more info would help.

 

[glacierbaze]

If you haven't found the base unit yet, try following the cable from the antenna to the radio.

 

[Antigua Larry]

What is the brand and model of the unit. I don't fully understand what you mean by "where is the main radio base" located. Usually the the main unit is the one with the dials buttons and screen. Do you have multiple handheld control units?

It is a Garmin VHF300. All that is visible is the handset, which is located on the lower part of the instrument panel. There has to be a radio unit somewhere.

 

[Fishtales]

Should be fairly easy to trace down. Make sure you disconnect and reconnect the power plug and the antenna each year. I've had issues with performance and the connector swiping seems to do the trick.

 

[seasick]

As suggested, trace the antenna wire.
If you go to this site, you will see what the box looks like

VHF 300 Marine Radio | Garmin

The Garmin VHF 300 marine receiver combines radio communication and 1 or 25 watts of transmit power with multi-station support to give you the flexibility and convenience you need to safely navigate and communicate on the open waters.

buy.garmin.com

I assume you remembered to hold the 16/9 button on the handset to turn the unit on.

 

[Antigua Larry]

I am bumping my old thread. I have been using a hand-held since we have stayed close to shore during COVID closures, but we are planning to go off-island next year, so I need to get this fixed.

The VHF300 transceiver was inside the console cover, behind the plotters. I had to remove a lot of caulking to get the cover off - that's a pretty bad design. Once done, I looked for any inline fuses to the VHF300, but there aren't any. There is one unmarked 10A fuse in the fuse box under the dash that was blown. As soon as I plugged in a new one, it blew. I disconnected power (through the NMEA0183 connector) to the transceiver, and a new fuse did not blow.

At this point, I am reasonably sure there is a short in the VHF300 transceiver. Since this is out of production, it would seem that my options are to buy a used unit (ebay has several) or buy an entirely different radio, and install it on top of the console.

Thoughts?

 

[Angler Management]

Thoughts: buy an ICOM. Install wherever you want.

I have the unit in the overhead cabinet and ran a extension for the mike to the dash.

 

[SkunkBoat]

Your vhf 300 was hidden. Guessing you have the Garmin speaker in your dash somewhere as well as the jack for the GHS 10 mic. You could probably replace with Garmin vhf 315 if you can’t find a 300. That might minimize installation changes.
I would pull the unit and test on a battery to isolate and exhaust all trouble shooting before buying something .

 

[Hookup1]

At this point, I am reasonably sure there is a short in the VHF300 transceiver. Since this is out of production, it would seem that my options are to buy a used unit (ebay has several) or buy an entirely different radio, and install it on top of the console. There is one unmarked 10A fuse in the fuse box under the dash that was blown. As soon as I plugged in a new one, it blew. I disconnected power (through the NMEA0183 connector) to the transceiver, and a new fuse did not blow.

Thoughts?

What's the scoop on this 10 A fuse? Does it connect to the VHF power cord?

When you say " I disconnected power (through the NMEA0183 connector)" do you mean the "Power NMEA I/O" connector?

I looked at your manual. It's a "black box" VHF. The power connector is clearly marked. May have a indicator light as well. Is the indicator light lit? Before you go replacing anything take the power connector off and use a voltmeter to test for power. I'm sure you could borrow a voltmeter if you don't have one. At least you will know if the unit has power when you replace the unit. If no power follow the power cord back, check fuse, back more to fuse block, re-check. This isn't really that complicated and a little patience will go a long way.

 

[Antigua Larry]

What's the scoop on this 10 A fuse? Does it connect to the VHF power cord?

When you say " I disconnected power (through the NMEA0183 connector)" do you mean the "Power NMEA I/O" connector?

I looked at your manual. It's a "black box" VHF. The power connector is clearly marked. May have a indicator light as well. Is the indicator light lit? Before you go replacing anything take the power connector off and use a voltmeter to test for power. I'm sure you could borrow a voltmeter if you don't have one. At least you will know if the unit has power when you replace the unit. If no power follow the power cord back, check fuse, back more to fuse block, re-check. This isn't really that complicated and a little patience will go a long way.

I have a voltmeter. I have measured 12V on the "Power NMEA I/O" connector, so I know the fuse I replaced is for the VHF power. As soon as I reconnect the power lead, the fuse gets zapped. I have no doubt that the radio has a dead short in it. The question is to replace it with the same unit - Marine Max has some units in Florida, that they claim have been tested, replace it with the newer version, or install a totally new radio outside of the console. We have the powered speaker already, which worked great, so I am inclined to go down that path.

On a side note, when this happened, the battery charger had failed and was putting out 28V instead of 14.4 - it killed the batteries, and I think perhaps the radio was damaged by the high voltage.

 

[Hookup1]

Agreed. The high voltage probably cooked the unit. Unless there is something about the old radio you don't like I would keep it original and buy a used tested one. A little more complicated for you being out of the country.

Do the new units ship with the remote microphone?

 

[Fishtales]

I am bumping my old thread. I have been using a hand-held since we have stayed close to shore during COVID closures, but we are planning to go off-island next year, so I need to get this fixed.

The VHF300 transceiver was inside the console cover, behind the plotters. I had to remove a lot of caulking to get the cover off - that's a pretty bad design. Once done, I looked for any inline fuses to the VHF300, but there aren't any. There is one unmarked 10A fuse in the fuse box under the dash that was blown. As soon as I plugged in a new one, it blew. I disconnected power (through the NMEA0183 connector) to the transceiver, and a new fuse did not blow.

At this point, I am reasonably sure there is a short in the VHF300 transceiver. Since this is out of production, it would seem that my options are to buy a used unit (ebay has several) or buy an entirely different radio, and install it on top of the console.

Thoughts?

I went with the Standard Horizon Explorer GX1800GPS after doing a bunch of research and asking around. Some things I like are a built in GPS, value I paid $207 shipped from the GPS Store on the net and ratings vs features. SH makes more capable units but this one had what I wanted at a decent price point.

 

[Antigua Larry]

Agreed. The high voltage probably cooked the unit. Unless there is something about the old radio you don't like I would keep it original and buy a used tested one. A little more complicated for you being out of the country.

Do the new units ship with the remote microphone?

The handset (GHS10) is separate - it was actually unplugged when the charger failed, so hopefully no damage. We are going back to Florida for the summer next month, so hopefully I can get a used replacement, and hope. If not, I can install a totally new non-Garmin set.

 

[grady23]

Does the Mic have a battery in it?

 

[Antigua Larry]

Does the Mic have a battery in it?

No, it is powered through the connector.