TomTom 730 squeeling when pluged in

[da_guy2]

First this is different that the Bluetooth squealing.

Whenever i plug the power in, the line out develops a slight squeal. It's not alot but its REALLY anoying after a little while. its essentaly an 1850 hz pulse that really gets amplified by my car stereo.

Anyone heard of this?

David

 

[lstoll]

Yep, I think it's called a 'ground loop'. It's the sound of your alternator, and if it's like my MP3 player the pitch will vary with engine speed. It's fairly common in car stereos when you start installing amplifiers in your trunk.

With amplifiers you solve it by running a ground wire between all of your components (head unit, amps, battery). When you're using a car charger, I'm not sure how to fix it.

You could maybe try running another ground wire from the cigarette lighter to a good ground location (heavy part of the dashboard frame, ground point in the fuse box, firewall, etc). Other than that, maybe a better quality charger? The one I have problems with is a cheap $2.00 charger off of EBay.

Lyle

 

[da_guy2]

Yep, I think it's called a 'ground loop'. It's the sound of your alternator, and if it's like my MP3 player the pitch will vary with engine speed. It's fairly common in car stereos when you start installing amplifiers in your trunk.

With amplifiers you solve it by running a ground wire between all of your components (head unit, amps, battery). When you're using a car charger, I'm not sure how to fix it.

You could maybe try running another ground wire from the cigarette lighter to a good ground location (heavy part of the dashboard frame, ground point in the fuse box, firewall, etc). Other than that, maybe a better quality charger? The one I have problems with is a cheap $2.00 charger off of EBay.

Lyle

Hmm I dont think this is the case. Two reasons.

First it does it when plugged into the computer which dosnt have an alternator or engine it still does it.

Second I can hear the alternator whine but its only very slight. This is much louder.

I have a feeling its related to the battery charger in the device but i'm not sure.

 

[Bama Rambler]

I think I'd be calling TT for a RMA. Sounds like you have a bad unit. Either in the charging circuit or the line amp. Either way it's return.

 

[da_guy2]

OK I'm sorry lstoll ya it was a ground loop issue, but it was slightly different.

Normally when you have a ground loop problem the current running accross the grounds causes resonance with the alternator. In this case my best is it was a DC-DC converter in the GPS that was resonating. Anyways I bought a Ground-Loop Isolator (which is essentially a 1:1 transformer that allows AC (sound) and stops DC ), plugged it in between the GPS and the AUX in in the car and it worked like a charm. Not a big fan of this ugly cable but I'll work out a more pretty solution eventually (like hiding it in the dash or something).

Thanks for pointing me in the right direction though

David