How to check polarity of power cable for LCD

**crash813** · 03-28-2006, 07:20 PM

Guys, I though this part would be simple but I'm somewhat worried since a mistake here might lose my lcd.

Anyways, I have an 8" screen that has the dc converter that connects to the VGA cable via a small pin. I was planning on cutting off the ac/dc brick and connecting it directly to my 12v source but the problem is how can you tell which wire is '+' and which is '-' ? One side has these long dashes on it, the other just electrical specs printed out.

Any ideas?

**spmclaugh** · 03-28-2006, 07:24 PM

Originally Posted by crash813

Guys, I though this part would be simple but I'm somewhat worried since a mistake here might lose my lcd.

Anyways, I have an 8" screen that has the dc converter that connects to the VGA cable via a small pin. I was planning on cutting off the ac/dc brick and connecting it directly to my 12v source but the problem is how can you tell which wire is '+' and which is '-' ? One side has these long dashes on it, the other just electrical specs printed out.

Any ideas?

What model? Pics?

If you have the original DC converter, just plug it into the wall and stick a multi-meter (DC mode) on the output pins...

**Cris** · 03-28-2006, 07:54 PM

Best thing is to measure it, and see. Don't rely on the lines of a cable...

**crash813** · 03-28-2006, 08:40 PM

figured it out guys............

Since I knew from the brick that the inside of the pin was positive simply did a continuity test to see which wire corresponded to the inside of the pin and which was the outside. Thought of it as soon as I posted.

BTW - looks like the cable with the dashes is positive.