Let’s say your laptop does not start at all. You plug in the power adapter and press on the power button, but the laptop will not react. It’s dead and the power or battery charge LED will not light up.
What could be wrong? Is it bad power jack or the motherboard is dead?
By the way, the power jack aka DC-IN jack is the power socket on the side or back of your laptop where you plug the AC/DC power adapter.
I’ll explain how to perform basic troubleshooting and find out what is wrong. This is only for experienced people, who know how to disassemble laptops.
First of all, test the AC/DC power adapter with a multimeter. It’s very likely that there is noting wrong with the laptop and your problem is related to the power adapter.
If the adapter tests fine and output correct voltage, disassemble the laptop and remove the top cover.
As you see on the first picture, in my laptop the power adapter plugs into the DC-IN power jack which is connected to the motherboard via a harness.
In some models the DC-IN power jack is soldered directly to the motherboard.
Plug in the power adapter and measure voltage at the point where the DC-IN jack or DC harness (like in my case) connected to the motherboard.
If you are reading the same voltage as on the AC adapter, it means the power jack or harness works properly and the problem is related to the motherboard.
If there is no voltage, most likely there is a problem with the jack or hardness and it has to be replaced.

By the way, in some case the problem could be related to the fuse which is usually located somewhere very close to the power jack/harness connector. You can test the fuse with a multimeter.

If the fuse is bad, the motherboard will appear to be dead even if there is nothing wrong with the power jack and AC/DC adapter. If that’s the case, replacing the bad fuse should fix the problem.
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April 18th, 2010 at 5:33 am
Hi,
I can’t find the fuse on my HPDV 9000 do you have any website or manual guide I could use to locate it?
Thanks
April 17th, 2010 at 10:43 pm
Mark,
I don’t think that your problem is related to the fuse.
Usually the fuse is located somewhere close to the DC jack (or DC jack harness). The fuse is soldered to the motherboard. In order to replace the fuse, you’ll have to desolder the failed one and solder a new one. Before replacing the fuse test it with a multimeter.
April 16th, 2010 at 2:11 am
Hi,
I have a HPDV9000.
I just sent it for a complete repair of the graphic chip, I then booted my laptop, everything was fine, image on the screen was normal; 30 minutes after it began to vibrate quite loudely somewhere around the fan or the hardrive ; I just pulled the AC/DC adapter right away and the battery was not plugged in. After that I tried to boot it but no reaction just the blue light where you plug the adapter.
I checked my ac adapter and the DC-IN harness, voltage is fine.
But I can’t locate the fuse on the motherboard, anyone has a pictures or a website that I could use?
How much does a fuse coast and is it easy to replace?
April 7th, 2010 at 4:59 am
Hello, I have an Acer Travelmate 2480 and my computer just won’t turn on. When I push the pwer button, an orange light flickers in the front by the speakers. This happens with and without the power adapter plugged in. Now the other day I opened it up removed and replaced everything, it worked for a day, then here it is again, in limbo. Any suggestions?
April 4th, 2010 at 11:34 am
Sure,
ac adapter works!
I can try to change the fuse?? But i don’t fount PF1 or F1 pin on motherboard pcb! Help me
April 4th, 2010 at 11:15 am
Korben,
Did you test the AC adapter? Maybe the adapter is not working properly when loaded. I would suggest testing the laptop with another known good AC adapter.
If the problem still exist, most likely this is the motherboard failure.
April 4th, 2010 at 11:00 am
Sorry… my pc is hp pavilion dv6693el.
April 4th, 2010 at 10:59 am
Hi,
Help me!
i have same problem…. pc works only with battery but not works with AC adapter,this one don’t charge the battery!
So i found the fuse, but it is ok… the tester sounds when i test it!
March 10th, 2010 at 2:48 pm
i have an acer tm 5520. with pomona motherboard. my battery was broken and laptop cudnt power on. i checked few things, assembled it back, and it was running again ( without battery ) i poured some glue on the power jack to fix it in the casing because it got loose. next morning i tried to fit in battery, but it didnt power on. and when i hooked it with adapter without battery it was dead. no l.e.d no power. its been dead since. i had it checked in the market but they cannot figure out the problem. when i check for ac voltage with a multimetre, it seems to get same volts on the ac jack as from adapter, but when i go further, multimetre detecs low volts.
i have another laptop same model. unlike above, it shows same voltage from adapter to ac jack and to battery terminal.
does anybody have any clue whats wrong with my computer? can u suggest me anything? thanks
March 3rd, 2010 at 10:02 pm
vince,
Here’s service manual for Acer Aspire 4720G, 4720Z, 4720 and 4320 series.
Now you know how to get to the power jack.
Good luck!