TV with 14v brick, okay at 12.x volts?
I'm looking at a Samsung TV which has a 14v power supply brick. I would like to run the TV directly off the DC side of the RV. I expect it would be pretty good in the range of converter voltages of 1...
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Snowman9000 wrote:
I found that I get an interference signal when feeding the DVD signal from the dash head unit to the TV, when the TV is directly powered by 12v. The interference goes away when I power the TV from 110v thru its brick. The brick 14v output cable has a small wart on it to do some kind of filtering or noise prevention. My homemade cig plug cable does not.
The TV works perfectly otherwise. The DVD is fed through low quality red/white/yellow AV cables. But as I say, it comes through fine when the TV is powered by its brick.
We hardly ever play DVDs,
We could power the TV by brick when we want to play a DVD,
Including by inverter if need be.
But I'm curious as to the problem.
It is known as a "ground loop".
Basically it happens when you have several DIFFERENT "grounding" points between devices.
Your DVD player is grounded in one place in the wiring harness and your TV is grounded in a DIFFERENT place. Connecting the video and audio grounds from the DVD to TV creates a "short cut" DC path between the two different grounds.
This creates very small current flow on the ground wire (AKA "shield") of the A/V cables. These currents makes the TV see "noise" on the grounds and the result ends up on the TV screen (lines or interference) and also the audio as a hum/buzz.
Using the AC power brick breaks or isolates the ground of the TV stopping the interference.
To get around the ground loops you need special isolation transformers for the video AN the audio.
THIS is an example of a VIDEO ground loop isolation transformer.
THIS is an example of a AUDIO ground loop isolator.
You WILL need BOTH to fix you problem...
