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How To Test Laptop DC Power Jack If It Is Broken

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  • Laptops
Last response: in Laptop Tech Support
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April 13, 2014 7:38:23 AM

I have a Compaq CQ62/HP G62 Notebook I'm trying to fix. It looks like a power related problem because when I plug it in to the AC adapter to the DC jack on the laptop, the side LEDs do not light up.

I tried wiggling the AC adapter into the DC jack, no good. So I took a multi-meter and I tested the AC adapter (input 10-240V/1.7A AC, output 18.5V/3.5A DC) and it comes out with the correct output voltage (around 18V-19V).

I took the laptop apart and I wanted to test the DC jack to see if that it is just not sending any power to the motherboard. However I'm not sure how to check if it is dead or not. There are 7 pins to the DC jack (3 on one side, 4 on the other). I cannot find a technical or spec sheet for this specific jack, so I don't know what is the output of these 7 pins.

If anyone knows what kind of outputs I should be seeing from these pins, I would greatly appreciate it, and it will help people from jumping the gun and going ahead and replacing the DC jack or their motherboard if they run into a similar problem like mine.

Picture of the DC jack:
http://i54.photobucket.com/albums/g109/chikyeung/DSC_07...

More about : test laptop power jack broken

a b D Laptop
April 13, 2014 7:46:47 AM

Some of those are for the LED on there, especially if it's a dual color LED to show charging/charged status, that would need maybe the 3, 2 powers and a common ground, or common power and 2 grounds. That would leave the 4 pins, which I would think might be 2 red's, 2 blacks, to help carry more power over thinner wires, so I would look at the 4 bank. If you can remove the heat shrink tubing a bit around the connector, you should be able to see the colors, and when in doubt, go red and black. lol. The outside shielding of the connector should cause a multimeter on connectivity settings to ground out and beep on the black wires and the center pin on the jack should connect to red.
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April 14, 2014 2:52:36 PM

Thanks for responding getochkn.

I exposed the wires and it looks like I have the following colored wires:
from left to right:Gray, white, brown, black, empty, tan, orange, red.

My guess is black is ground. The tan, orange, and red read 18.3V, 19V, and 19V respectively. The other 3 pins that are not ground do not show any voltage, and the LED does not light up. Do you think the fact that the LED on the DC jack does not like up indicate that the DC jack is busted?
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a c 254 D Laptop
April 16, 2014 6:08:26 AM

Hi, your DC jack is fine, the laptop powers the LED, so they do not light up if they are not connected to the motherboard.
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April 16, 2014 12:44:41 PM

jarotech said:
Hi, your DC jack is fine, the laptop powers the LED, so they do not light up if they are not connected to the motherboard.


Yeah, the LED on the Jack does not like up at all. With or without the laptop motherboard.
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