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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August 10th, 2008 at 11:03 pm
bernard,
You can try disconnecting the CMOS battery for a while but I’m not sure if it will help.
If your laptop failed while upgrading the BIOS, for example it lost power, it’s possible that the BIOS got corrupted. If that’s the case, you’ll have to replace the motherboard.
August 10th, 2008 at 10:39 pm
my laptop is dead due to bios setup, how can i reset a cmos on motherboard.. thanks
August 10th, 2008 at 10:31 pm
Tony,
Did you test the laptop with an external monitor? Maybe the laptop itself works fine but there is a problem with the LCD screen. It’s possible the video cable got disconnected from the LCD screen and because of that you have no video. Can you see external video?
Yep, that’s Wi-Fi antenna cables.
August 10th, 2008 at 10:23 pm
Jeremy,
Try removing the hard drive and powering up the laptop. Will you get any video on the screen when the hard dive is removed?
August 9th, 2008 at 4:55 pm
My Niece closed my laptop screen down very hard in a fit of anger at her brother and now the Laptop will not display. Have a compaq presario c500. Is there a micro switch or sensor that could be suspect? When the laptop worked before, the laptop when closed would power down the machine. I have taken it most the way apart, but cannot see a micro-switch anywhere around the hinge area or LCD. Left hinge contained the display cable, Right hinge contained a black and a white wire that snake through the bezel of the LCD and terminate on 2 different side into some type of clip. I believe it may just be the leads for the Wifi antenna, but perhaps not. I would like to find the schematic for it, but have had no luck finding it (yes I checked your documentation) Any other advice?
August 9th, 2008 at 10:30 am
It’s frustrating. The M35 when in failure mode lights up and charges and runs fan for 1 sec.but no boot.
Upward pressure on the dc jack enable it to boot normally.
Once running , the slightest shock (hitting a key e.g.or moving the lid)) will stop it. Evidently there is a systemboard crack near the back but after removing the pcb and staring at it thru a glass, until blue in the face, I cant see it. I’ll never trace the open circuit without a schematic
Right now I have a piece of foam wedged under the dc jack doing upward pressure. I have switched away from Toshiba.
August 5th, 2008 at 6:09 am
Alright here is the problem.
At first my Presario would boot up fine and run. But the slightest movement such as shifting with it in my lap would cause the screen to either go blank or create vertical lines. It would work perfectly still on a desk. Now I have gotten to the point where it wont boot up all the time. The fan will spin the power light and wireless light come on but the hard drive light will flash x2 in a repeating fashion. It also has a very low audible sound it makes when the hard drive light flashes. Any advice would be appreciated.
July 30th, 2008 at 8:22 am
may be you already test basic troublesooting..hope i can help you..try to check the inverter b+,swichting,sensor,adj….using the volt meter,usually in normal condition that pin have volts..if okay replace the inverter..if no b+ posible the problem is with in the mother board, check the failure of switching circuit of backlight nare the video connector on motherboard usaully they use transistor..NOTE: ONLY FOR SERVICE PERSONEL.
July 29th, 2008 at 9:35 pm
gil h. lariosa,
Did you test the laptop with an external screen? The image disappears from both screens, internal and external? Could be memory problem. Try reconnecting the memory module. Test your laptop with another working memory.
July 28th, 2008 at 1:37 am
ihave my laptop when i press the power on the led is ligth but ther is no emage on lcd . sometimes when i push thepower on the have image and run normaly . when i shutdown the computer and re start it again no moreimage on the lcd .can you help me on my problem. anyway mylaptop is syntax model a530.