HomeLet’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.
February 1st, 2012 at 6:29 pm
@ Daug,
Most likely it’s either bad AC adapter or failed DC jack inside the laptop.
1. Test your AC adapter with a voltmeter. If voltage cuts off when you move the cable, probably there is a short inside. Replace the AC adapter.
2. If your AC adapter works properly, most likely there is a problem with the DC jack.
Take a look at this guide. It explains how to access and replace DC jack harness on Compaq Presario CQ50, CQ60 or CQ70 laptops.
http://www.insidemylaptop.com/remove-motherboard-from-compaq-presario-cq50-cq60-cq70-laptop/
The DC jack harness shown on the last picture. Try replacing it. Do not replace the motherboard. Try replacing just the DC jack harness first.
February 1st, 2012 at 4:17 pm
@ Sam,
Fuses soldered to the motherboard. If the fuse failed, it’s necessary to locate it and desolder. After that solder a new fuse.
Sorry cannot help here. I’m not fixing motherboards on the component level.
February 1st, 2012 at 8:35 am
@ yaro,
You are welcome.
You should have started with testing the AC adapter though.
February 1st, 2012 at 4:43 am
Mate I have a CQ50 and it won’t charge….unless I slowly pull the powerplug out of the socket and hear a few clicks and then plug it straight back in…or sometimes if I change power outlets completely. THE HELL??? lol. Any ideas?
I’m || this close to ordering a new motherboard but want to know 100% what other problem it could be. Any help would be much appreciated!
January 29th, 2012 at 8:44 pm
How do I replace the fuse?
January 27th, 2012 at 6:06 am
Mate you’ve just made my day. I stripped my laptop int small piees and couln’t figure out what’s wrong with it. Power likght blinking but nothing when pressed the power button. Then I found your excellent article and I thought I test the PSU… 12V instead of 19. Connected another one and now all works perfectly. Many thanks
January 19th, 2012 at 1:41 pm
@ olusegun,
This sounds like motherboard failure to me. I’m afraid there is not much you can do besides replacing the motherboard. Probably the laptop not worth it.
January 18th, 2012 at 1:45 pm
Hi,,, I have Hp HDX 16t. What did happen???
It was working fine. One day battery died and it went to hibernation by it self as i set so. After few hours i tried to restart without charger plug in (as i did not remember that battery died) and it got stuck in middle of process. At that time it was showing speaker panel light and CPU light steady. So i plugged in charger but the charging light ( at front near by light indicating cpu function) did not turn on even though the light nearby plug in socket was on. Then i tried to turn off by pressing start button for a while but it did not turned off. SO i removed battery. Since then its not showing any light at all.
What may be not function???
DC POWER JACK??
FUSE?
MOTHERBOARD???
Does mother board can get crashed in such a way????
any idea what should do??/
January 17th, 2012 at 10:26 pm
my laptop HP g61 does not power on either
with battery or when connected to the
mains supply(AC). whenever i press the
power botton the battery lit in the front of
the system will only blink for about 3
seconds without the system been power on
(the fan,the keyboard light nor the power
botton lit will not on) i try to remove the
battery nd press the power button for 30
secs before putting it back,still their is no
respond. but i discovered each time i
remove the battery and plug it to the
Mains,the indicator power light beside the
plug of the system will lit for about 3
seconds before it went off again.i have
checked it with another charging adapter all
to no avail. pls ,help me out.
January 17th, 2012 at 6:13 pm
@ CSS,
It’s possible.
In a HP dv7 notebook the DC jack attached to the power cable which can be easily unplugged from the motherboard. The best test would be replacing the DC jack harness which cost less than $10.
I published HP dv7 disassembly guide here: http://www.insidemylaptop.com/disassemble-hp-pavilion-dv7-notebook/
New replacement DC jack harness available here.