In this post I’ll explain how to troubleshoot a dead laptop and find the problem. The following troubleshooting tips are not model and brand specific, they should work for most laptops.
Let’s take a look at two different scenarios.
Example 1. The laptop is absolutely dead.
When you plug in the power adapter and press on the power button, there is no signs of life at all. The laptop will not make usual noises, LEDs will not light up, the fan will not spin, the screen is blank and black, etc… In short, the laptop is dead.
What you can do in this case?
1. Make sure the wall outlet is working and the laptop DC adapter is getting power from the outlet. Try another wall outlet.
2. Test the laptop DC power adapter, make sure the voltage output is correct. You can test the DC power adapter with a voltmeter.
3. Let’s say the DC adapter is fine and the adapter outputs correct voltage. In this case unplug the power adapter from the laptop, remove the battery, wait for 1-2 minutes, plug in the adapter and try turning on the laptop again.
OK, you tested the adapter and it’s bad. If you decide to replace the original DC adapter with a generic one, you’ll have to follow this rule:
The voltage output on your new adapter has to be exactly the same as on the original adapter. The amperage on the new adapter could be the same or higher.
If nothing helps and the laptop is still dead, apparently the motherboard is fried or there is a problem with the DC power jack. It’s possible the DC power jack is broken and the motherboard is not getting any power from the adapter. In this case you’ll have to disassemble the laptop and replace the power jack. Check out this guide for fixing laptop power jack.
Example 2. When you plug the DC power adapter and press on the power button, the laptop starts making normal noises, the LEDs work properly but noting appears on the screen. The laptop will not start.
First of all, take a closer look at the LCD screen. Look at the screen under bright light. It’s possible that the image is still on the screen but it’s very faint. If that’s the case, check out these tips for troubleshooting laptop with backlight failure.
If there is no image on the laptop LCD screen, test the laptop with an external monitor. Connect an external monitor to the VGA port on your laptop and turn the laptop on. You can toggle video output between the internal LCD screen and external monitor by pressing Fn and F4 keys simultaneously on HP laptops, Fn and F5 keys on Toshiba laptops, Fn and F7 keys on IBM laptops. Other laptops may use different key combinations.
Let’s say the external monitor works fine but the internal LCD screen has no image at all. If that’s the case, your problem could be related to the LCD screen or the video cable. Also, make sure the video cable makes good connection with the motherboard and the LCD screen. Try reconnecting, reseating the cable.
In my case, both internal and external monitors were absolutely dead. Neither of them had image. That means the problem is not related to the LCD screen or the video cable. From my experience I know that this problem could be related to the laptop memory.
Try reseating the memory module, maybe it’s not making good connection with the memory slot. Try cleaning contacts on the memory module with pen eraser. Try moving the memory module into another slot. Try replacing the memory module with another known good module, it’s possible that your original module is dead.
If you have two memory modules installed you can try removing them one by one, it’s possible that one of the modules is bad. Try installing different memory modules into different memory slots.
In my case reseating, swapping the memory module didn’t help. I was pretty confident that my problem is not memory related and I moved on.
Try removing battery, hard drive and DVD drive and turning on the laptop without these components.
Also, try turning on the laptop with an external monitor when the video cable is unplugged from the motherboard. If the laptop start with video on the external monitor, apparently there is something wrong with the laptop display panel.
In my case removing the hard drive and DVD drive didn’t help. Unplugging the video cable didn’t help either.
I continued taking my laptop apart piece by piece and tested it after each step.
I removed wireless card, modem, disconnected the keyboard but it didn’t help.
I still wasn’t able to boot the laptop with video on the external monitor.
Finally, I disassembled the laptop and removed the motherboard.
On this picture you see my final test. The motherboard has been removed from the base and I assembled basic barebone system on my bench.
1. Motherboard. Like on most laptops, in my case the video card is integrated into the motherboard
2. CPU with heatsink and cooling fan.
3. Known good memory module.
4. The power button board witch I need to turn on the system.
5. Working DC power adapter.
Still cannot get any video on the external monitor. The system turns on, the cooling fan starts spinning but there is no video.
At this point I’m 95% sure that the motherboard is dead. CPU failures are not very common, so it must be bad motherboard.
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April 24th, 2010 at 2:32 pm
Leon27,
Most likely it’s either corrupted OS or the hard drive is bad.
If the hard drive works while connected to another computer, there still could be a problem with the hard drive. Maybe it has a bad sector somewhere at the beginning, where all boot files are located.
Here’s what you can try:
1. Try reinstalling the OS from scratch.
2. Test your hard drive. You can use Hitachi’s drive fitness test, it works well with most hard drives.
If the hard drive fails test, replace it with a new one and try installing OS again.
Also, check laptop memory. Do you have two memory modules installed? Try removing them one by one. Test the laptop with each module installed one at a time.
April 24th, 2010 at 1:49 pm
Absolute Zero,
Does it happen mostly when you move the laptop? If yes, this could be motherboard failure. Apparently the motherboard has a faulty solder joint or crack somewhere and when you move the laptop, you actually flexing the motherboard forcing it to fail.
April 24th, 2010 at 1:39 pm
Mazhar,
It’s possible there is a damaged fuse on the motherboard. Most likely you can find the fuse somewhere close to the DC jack.
It’s necessary to remove the motherboard and take a closer look at the motherboard (DC jack area). When you find the fuse, test it with a multimeter. If the fuse is bad, it has to be replaced.
This is just a guess.
April 24th, 2010 at 12:50 pm
Marijan,
Sounds like the motherboard failure to me. I doubt this is the power button failure.
When you press the power button, the system turn on, right? That means the power button works properly.
Again, I think this is the motherboard failure.
April 22nd, 2010 at 12:38 pm
The laptop is HP Compaq NC6000.
When i power on the laptop fan spins for 4-5 seconds and turn of !
No image on the screen , no nothing .
I took out the board and connected on external monitor with good memory module , replaced cpu, power adapter is good ( no other component is connected ).
Simptop is the same : turn on by itself , stays on for 4-5 second and then turn off again .
This board have a Power Button Board on it, maybe there is some short circuit ?? Maybe this is common issue with this laptop series ? Dont know .
Any help appreciated .
Regards.
P.S. Sorry for bad English
April 14th, 2010 at 12:30 pm
I have Compaq HP Nx7400, its wonderful toy, unfortunately on my power supply cable had s short circuit on the lower-voltage end (there was a spark) of course my power supply is gone, but the unit stop to response on the new power supply too, laptop is dead with or without power supply, I had 2nd battery as I replaced it, laptop come on but it wont charge nor recognise the power supply connected, i am afraid if charging system got burnt, I am asking is there any short circuit prevention switch on these laptops, otherwise what would be possible damage and how to repair it,
Mazhar
April 11th, 2010 at 10:55 pm
May I ask something?? My laptop will face the problem of suddenly out of power and then restart, although I had put on the battery(full charge) it still face the same problem. Just suddenly black out (like no electricity supply) then restart. Sometimes, the computer is hank and the screen is flawad sometimes. Thank you.
April 11th, 2010 at 12:23 pm
Ok my laptop, has a problem and is when I try to turn on, won’t boot the HD everything else is working led are on even in the screen you see a cursor blinking but the LCD is in black, is like when you try to install a new operation system but nothing come up. I take the HD out and plug in to my desk top a it working, is like when try to boot the HD can’t do it, DVD is working, I also try to change the boot sequence and nothing work, I don’t know what else do, thank for your time.
April 1st, 2010 at 4:51 pm
I have an Acer Aspire 1640 series and it shows no sign at all of trying to power up.
The charger is fine but I have tried the charger from another 1640 series unit.
I get NO lights at all ,no fan , not a thing – except for a very feint, very high pitched sound coming from the centre of the motherboard.
The battery is showing 0.10 Volts so I assume the power from the charger is not reaching the battery at all.
I have stripped the laptop down in order to check for obvious signs of a problem, with the charger plugged in and switched on I can find 19 Volts at various points on the motherboard (using a digital multimeter).
I am not getting continuity between either the + or – terminal of the charging socket – and any of the terminals that connect with the battery.
Any suggestions would be appriciated.
March 24th, 2010 at 7:33 pm
Great guide. Straightforward, simple and effective. Took out a bad memory module and got my laptop back. Hooray!