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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September 15th, 2008 at 8:15 pm
Karen,
The first thing to try would be replacing the memory module with another one. Your description sounds like a problem with the memory. I could be wrong, but replacing the memory module would be the first thing to try.
September 15th, 2008 at 8:10 pm
Kasan,
Could be bad memory. I would try replacing the memory module with another known working module.
September 15th, 2008 at 8:08 pm
Rich,
So, when you tapping on the lid close switch the laptop sometimes starts fine, correct? Try this. Remove the keyboard bezel – the plastic cover above the keyboard and try turning the laptop on without this cover. Can you?
If the laptop starts fine without the cover, most likely there is nothing wrong with the lid close switch which is soldered to the motherboard but there could be a problem with the white button attached to the keyboard bezel. Apparently, the white button is not seated correctly and when you install the keyboard bezel on the laptop it’s pressing on the lid close switch all the time. Take a closer look at the button on the keyboard bezel.
September 15th, 2008 at 6:17 pm
HELP! My daughter has a Compaq Presario V3000 laptop. She said she was posting on http://www.myyearbook.com when it “crashed”. I started it up and the hard drive made 2 booting noises and then stopped but the screen never lit up. I tried the HP guide steps- reseating the memory and then let my brother try to boot from an install CD. He felt it was a hard drive problem. I purchased a new hard drive tonight from Best Buy and am attempting to use my other daughter’s Recovery CDs to reboot. I’m on CD6 (out of 10) and have still not seen any flicker on the screen. I hooked up my desktop monitor to the laptop during this process and the screen was blank.
From what I’ve read, this may be the motherboard. I’ve put $85 in it already (with the new hard drive) and need to know where to stop. Last Christmas I bought the younger daughter a very similar laptop for $399. It looks like replacing the motherboard is going to cost another $200 and I’m not guaranteed that will work. Is there a way I can rule out everything else and know that it’s just the motherboard?
Funds are very tight right now but I HAVE to get her off my computer. As a rule, I was reformatting her laptop every other month because of irreparable viruses (virii?) and/or spyware or some other incompatible program she downloaded.
Any ideas?
September 15th, 2008 at 5:53 pm
I have a dead Benq Joybook 7000 with beep sound very loud.
It is already broken a year ago and I have tried to ask the benq service centre about this problem. They said it is a main board failure and it cost about $ 300.
After I found this very useful web site, I try to implement all the advice but still don’t work for it. From reseating the memory, remove the hard disk, remove the battery, remove wifi and modem, and test it with external monitor.
The symptom is like this: if I press the power button, the light indicator glow normally and the beep sound is loud with no picture in LCD. After I press and hold the power button again, the beep sound stop and the laptop shut off. But if I try to press the power button once again, the processor fan spin with no beep sound but the LCD still blank and seems the laptop not working at all.
I really need any advice to fix my laptop problems.
Thank you.
September 15th, 2008 at 4:02 am
Satellite m35x, just fixed the dc input worked well, however now I can not get it to boot. I traced it to the little switch that sticks up out of the case, the standby switch I guess. When you close the cover it puts the computer on standby. I know this is the problem because if I figit with it it will eventually get the computer to work. I am thinking it is a bad swith or connection to the board. Anyway to replace or repair this? Where would I find a new one? Please help!!!!!!!
September 13th, 2008 at 5:16 am
Same problem. Thanks for the graphics. Got some idea now!
September 13th, 2008 at 2:30 am
Reading laptop BIOS Post Codes with a second PC
I have purchased a Post Code Adapter but it’s readings make no sense to me.
My faulty laptop is a Toshiba S2450-S203, after switch-on the following front LED’s are
lit: DC IN 15V, Power, Battery & Disk. There are no beeps and nothing on the screen.
I do have the post code meanings but the final reading for the adapter at parallel port of
my faulty laptop was 00FF and before that LP__, END_, 5005, then flashing numbers.
These do not tell me what is wrong.
Because the post codes are issued to the parallel port I would have expected that
someone would have written a program to log these messages on another PC via a direct
parallel port cable connection. Does you know of any such software?
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September 9th, 2008 at 8:44 pm
Jose,
Take a closer look at the power jack. If you have a voltmeter, you can test if the power gets to the motherboard when the power adapter is plugged in.
If the motherboard gets power from the adapter but has no signs of life, it’s possible that you have a blown fuse witch can be replaced by a technician with some soldering experience. If the fuse is OK, most likely there is a problem with the motherboard.
September 7th, 2008 at 7:14 pm
i have a dead dell inspiron model PP10L.
my dell was working fine then all of a sudden it will not turn on. no lights no noise no sign of any life in it. i tested to see if we had power to the power cord/adapter and i get the 20 volts. we now that is ok i have removed hdd, battery, and still no sign of life. i was thinking the maybe it is my dc jack. when i plug the cord to the laptop there is a little play but it does not matter if i wiggle the cord in any direction and attempting to power up its still a no go. i guess i need to take the laptop apart and see if the jack is broken or loose. has anyone had any problems of this kind with there dell. thanks