Garmin 12volt Cord Whining Noise

[Flakarter]

I just bought a Legend C, which I also use in the car, hooked up to the 12v power cord.

 

I noticed that everytime I turned on the backlighting, there would be a high pitched whine in the car. I couldn't tell where it was coming from, so I put the gps to my ear. No noise. I shut off the backlighting, no noise. Backlighting on, the noise came back. I unplugged the 12 volt cord, and voila! The noise went away, regardless of whether or not the gps backlight is on or off.

 

It appears that the cord itself is some how causing the whine, and the noise is probably coming over the car speakers, but only when the backlighting is "on" on the gps. And this happens in both our cars.

 

Anybody else have this problem?????

 

Any solutions?

 

I plan to call Garmin in a few moments, but I thought I would share the problem.

 

Dean

[+Butano]

I haven't experienced this problem (I have a Garmin Legend). However, when I transfer data to or from the GPSr and am on my corded phone, I hear the data transferring in my phone. But that only occurs when I have the Garmin cord next to the handset cord. That whine though would bug me though.

[peter]

The backlighting on many devices requires fairly high voltage so there's a switching regulator to step up the battery voltage and this usually operates at a frequency in the audio range. On quite a few models I can faintly hear a high hum when the backlight is on and I hold the unit up to my ear. Apparently the power cord is tranmitting this frequency to your car speakers.

[Flakarter]

Garmin is sending me a new 12v cord, to see if it is a cord shielding problem.

[+fizzymagic]

It's not the cord. It's the backlight.

 

My new Palm Tungsten is particularly bad at this.

[Flakarter]

But the noise only occurs when the backlight is on and the gps is plugged into the 12v cord.

 

Without the 12v cord, no noise when the backlight is on.

 

Hmmmmmmmmm.

 

Dean

[+Crystal Sound]

The "power cord" on many units, as well as the circuits that power the backlight, often use a switching power supply. As my hearing is rather sensitive, I can hear MANY devices' power supplies while in operation. Usually I hear the sound coming from the supply itself (or the unit with the backlight) - but i have found a few times when such a unit has interfered with something and the noise comes out of the speakers of the affected unit.

 

Its possible there's a shielding or filtering issue. Trying the new cord Garmin is sending would be a good try.

 

You said it's coming from the car speakers.... Is this with the radio off as well as on?

 

By chance, are you listening to AM radio? AM is *VERY* susceptable to interferece. If so, do you still have this problem with FM ? How about where you are tuned? I've noticed i sometimes get more noise in my car, when i'm tuned to "lower" stations, than the "higher" stations.

 

As Butano commented, I have legend also (not the legend C) and havent noticed this issue.

 

Try the new power cord - if that doesnt help, try checking a few things I mentioned above, let us all know what your results are. OH yea, and keep working with Garmin - their customer service is really good. I'm sure they will do all they can to help.

Edited July 15, 2005 by Crystal Sound

[Flakarter]

FYI, I received a new 12 volt (12v) cord from Garmin as a warranty replacement. No more whining or humming noise. And the old cord does still whine/hum, so..............., it was the cord! Thanks Garmin.

 

By the way, Germin sent me a new cord, 2 day air, and didn't request return of the old one, and didn't ask for proof of purchase or warranty card or anything. Amazing. In the 5 years I've been dealing with Garmin, their customer service has always come through with a reasonable solution to any problem.

 

Now, I'll go to work trying to figure out why the screen jumps around while the gps is still. That occurs regardless of which map screen is on, and regardles of WAAS being on or off, and regardless of whether track is up or north. Hmmmm.

 

Dean

[+Crystal Sound]

Glad to hear it all worked out for you.

 

Chalk another one up for Garmin's excellent customer service.