Troubleshooting backlight failure

This laptop came for repair because of the LCD screen backlight failure. My customer complained that the laptop LCD screen is black but the laptop works with an external monitor.
Here are my steps for troubleshooting this laptop with the backlight failure.
First of all, I tested this laptop with an external monitor connected to the VGA port and the external monitor worked absolutely fine. I was able to get crystal clear image on the external screen even though the internal screen didn’t light up. If the external screen works fine, then most likely there is nothing wrong with the video card.
Notebook display assembly diagram
After that I took a closer look at the laptop LCD and noticed that the screen is not completely black. The laptop screen still works but the image is very very dull, you barely can see it. It means that the screen still gets data signal from the video card, but for some reason the backlight lamp doesn’t work.
From my experience I know that this problem can be related the lid close switch, faulty inverter board or bad backlight lamp. I checked them one by one.
If you have a similar problem, make sure the lid close witch moves freely. The lid switch is a small button located close to the LCD screen. This button triggers the hibernation or sleep mode when the screen is closed. If the lid close switch is dirty, it might get stuck inside the laptop case and cut off the power from the inverter board. The inverter board works as a power supply for the backlight lamp and if there is no power coming to the inverter board, the backlight lamp will not light up either.


In my case the lid button worked properly, it didn’t stuck inside the case. When I was pressing on the button very fast, I was able to light up the screen but only for a fraction of a second. The image wasn’t bright and it had a pinkish tone. A pinkish tone usually indicates a problem with the backlight lamp, not the inverter board.

Even though I suspected the backlight failure, I decided to test this laptop with a new inverter board just in case. But it didn’t help. The screen didn’t light up even after I replace the inverter board. So, I was right, this problem is not related to the inverter board.

Finally, I disconnected the screen backlight lamp connector from the inverter board and connected my test backlight lamp (I removed it from another cracked screen). You can find a new backlight lamp on eBay. Try to find a backlight with the connector already attached to it, so you can plug it into the inverter board. Make sure the connector on the backlight lamp is similar to the connector on your LCD screen.

As soon as I turned on the laptop, my backlight lamp lighted up. Yep, that’s the problem. The laptop screen has a faulty backlight lamp.
Here’s another laptop with backlight failure
This laptop video fails in a little bit different way. In this case the backlight lamp hasn’t failed completely.

The laptop starts with video on the screen but the background has reddish tone, the screen flickers and it makes noticeable buzzing noise coming from the backlight and inverter area. After a few minutes the backlight turns off by itself and the buzzing noise stops. When the backlight is off, the image on the screen is still visible but it’s very dark.

I removed the screen bezel and connected my test backlight lamp.

My test backlight works absolutely fine. The lamp doesn’t flicker and there is no buzzing noise. So, this laptop needs a new backlight lamp.

Removing and replacing keyboard

These instructions will help you to remove and replace keyboards on various laptops. I will not be able to cover all models but you’ll get the idea. Steps for removing and replacing the keyboard are similar for most laptops.
If your keyboard is missing a key, it’s not necessary to replace the whole keyboard. You can fix it using this guide: how to fix keys on a laptop keyboard.
Warning!
– if your laptop is still covered by the manufacturer’s warranty, do not open the case or you can loose the warranty.
– always remove the battery and unplug the AC adapter before you open the laptop case.
– if you damage the keyboard connector on the motherboard you’ll have to replace the whole motherboard.
– proceed on your own risk.
Sony laptop
I took these pictures from a Sony Vaio PCG-K33 (model PCG-9S1L) notebook. Should be similar for some other Sony notebooks too.

Insert a small flathead screwdriver under the keyboard bezel and carefully lift it up. Continue releasing plastic latches and removing the keyboard bezel with your fingers.

Be careful, on some models the bezel might be connected to the motherboard as it shown on the picture above. If you accidentally pulled the cable, connect it back. It is not necessary to disconnect the keyboard bezel from the motherboard in order to remove and replace the keyboard, just put it aside so you can access the keyboard screws.

Remove three (or more) screws from the top of the keyboard. Carefully lift up the keyboard from the laptop case.

The keyboard connects to the motherboard via a flat ribbon cable. Before you pull the cable from the connector, you’ll have to unlock the connector.

The image above illustrates how to unlock the keyboard connector. Carefully move the connector lock 2-3 millimeters up and after that pull the keyboard cable. To install the keyboard, follow the above mentioned steps in the reverse order.
Toshiba laptop
The following pictures were taken from a Toshiba Satellite A135 laptop. The keyboard removal instructions will be almost the same for most modern Toshiba laptops.

The keyboard bezel removal procedure is similar to the above mentioned Sony Vaio laptop. Lift it up with a small screwdriver and remove using fingers. On most Toshiba laptops the keyboard bezel doesn’t have any circuit board underneath, it’s just a piece of plastic and you don’t have to worry about cables.

After the bezel is removed you get an access to the keyboard screws. Remove two (or more) screws. Release the plastic latch pointed with the red arrow and lift up the keyboard. Carefully put the keyboard aside so you can access the connector underneath the keyboard. Do not forget that the keyboard is still connected to the motherboard.

Before you remove the keyboard, you’ll have to open the connector and release the flat ribbon cable.

Here’s a closeup picture of the keyboard connector on the motherboard. Be careful, this type of connector is fragile. On the left image the connector is closed. On the right image the connector is opened. Unlock the connector by moving the lock up as it shown on the right image and after that release the ribbon cable. Remove and replace the keyboard. For assembly instructions follow all the steps in the reverse order.
UPDATE. What can you do if the keyboard connector was damaged?
If you are looking for laptop disassembly instructions, check out laptop service manuals.

Toshiba Satellite model M35X power connector fix

Toshiba Satellite M35X model is known for it’s power connector problem. This issue has been covered on this blog a few times before in the following articles.
Toshiba Satellite M35X and Satellite A75 power jack and battery charge problem
Failed power jack workaround (guide for a Satellite A75 notebook similar to Satellite M35X)
Here’s another well written and documented guide submitted by Stephen Macuch. Thank you Stephen for the great pictures and very detailed instructions.
This is a view of the laptop power connector before the repair:

Inside the yellow circle is the main power connection from the connector to the board – note that you can see a dark circle completely around it, indicating that there is no solid metal connection.
Also note that it looks somewhat ‘burnt’ – this is indicative of sparking taking place. This connection carries 3 amps of current. The current then passes through the component labeled PF1 ( literally ‘Power Fuse 1’). It then is supposed to connect to this side of the part circled in red (‘PL1’) – but notice that flexing of the board as the connector was wiggled caused a crack you can see running horizontally under this end of this part.
Same view, after the repair:

The green coating covering the metal leading up to the power connector was scraped off down to the bare copper of the board, in three places – the center pin, circled in yellow here, and the connector pins on both sides (see below). All were resoldered – on the top side of the board first, then touched up on the bottom (which is not where the primary electrical contact is made). The new broader, smoothly-tapered connection will be both physically stronger, and a better electrical connection.
Inside the red circle, you can see this was done for other part (PL1), as well.
Bottom view of connector, before the repair:

Again note that inside the circled areas, you can see dark circles where there should be solid metal, indicating that the original physical connection has been broken, and the parts are only transferring power due to the fact that they are touching . In fact, the only thing even holding the connector to the board is the connection in the bottom middle (between the two lower yellow circles) and it has a crack in it, as well.
Notice, also, the dried flux residue, indicating that this bottom-side soldering was done entirely, or touched up, by hand – and not cleaned afterwards.
The actual metal that conducts the power is actually of the top side of the board, where the connector is mounted, but the fact that the solder that flowed through mounting holes has cracked indicates is was not properly soldered in the first place.
As you can see in the two views below, all solder joints between the connector and the top side copper on the board now look much better. Increasing the size and coverage of the solder joints to the metal sides of the connector will make its mounting to the board physically much stronger as well, and better able to resist any side-to-side or up-and-down forces.


Inside the red circles, you can see that both sides of that part PL1 have been well resoldered.
This bottom view of the board after the repair shows good flow of solder through to the bottom side at the time the joints were resoldered.

Here’s another common problem with this model:
Laptop locks up, freezes up or reboots when you touch the speakers

Laptop does not start. Fixing the problem.

If your laptop does not start at all or it starts but will not boot properly, it’s possible that you can fix the laptop at home without taking it to a repair center. Here are some troubleshooting tips for you. I’m not sure if I can cover all situation at once, so I will update this post as more examples come into my mind.
Situation 1.
The laptop appears to be dead. You plug the AC adapter but the LEDs (power light, hard drive light, battery charge light, etc…) do not light up and the laptop will not react at all if you press on the power button.
First of all in this situation check the AC adapter. You can test the output voltage with a voltmeter. If you cannot do that, find a known good AC adapter and use it for testing the laptop. It is possible the laptop appears to be dead because the AC adapter is bad (and the battery is discharged). If you know that the AC adapter is working properly and it outputs correct voltage but the laptop is still dead, most likely you have a power issue on the motherboard (or power board on some laptops) and it has to be replaced.
If you have to replace the AC adapter, make sure you use a correct one. The output voltage must be exactly the same as on the original adapter. The output amperage has to be the same as on the original adapter or higher, but not lower.
Situation 2.
When you plug the AC adapter the power LED and the battery charge LED light up. When you press on the power button the laptop powers up but will not start. There is no video on LCD or external monitor.
If the power LED lights up it indicates that the laptop is getting power from the AC adapter. Most likely there is nothing wrong with the adapter but just in case test it with a voltmeter to make sure the output voltage is correct.
Also try this. Unplug the AC adapter, remove the battery and wait for 1-2 minutes. After that plug the AC adapter ans try starting the laptop again. Sometimes this trick helps.
It also could be a memory related problem. Try reseating the memory module, just remove it from the slot on the motherboard and install it back. Try installing the memory module into the other slot (if it’s available). If you have two memory modules installed, try removing them one by one and start the laptop just with one memory module installed.
If the laptop starts fine with one memory module in both slots, but will not start with the second memory module in both slots, the second memory module is faulty. Replace the module.
If the laptop starts fine with both memory modules when they are installed in the slot A, but will not start with both memory modules installed in the slot B, the slot B is faulty and you’ll have to replace the motherboard or use only one memory slot.
Situation 3.
When you press on the power button, the laptop makes a series or short and long beeps and will not start up. There is no video on the screen.
In this situation test the memory module as I described in the situation2. Try installing a known good memory module. Most likely you are getting a beep error because of a faulty memory.
Situation 4.
You start the laptop. It sounds like the laptop is booting normally (hard drive LED is flashing) but there is no video on the screen
In this situation test the laptop with an external monitor. If the external screen works fine but there is no video on the laptop LCD, most likely there is a problem inside the laptop display assembly. Go to my previous post witch covers laptop video problems in more details.
Situation 5.
You start the laptop and it starts making repetitive clicking noise or grinding noise.
Most likely you hear this noise because of a faulty hard drive. You can remove the hard drive and start the laptop without it. If the noise is gone, the hard drive is your problem. Replace it.
If the laptop makes clicking or grinding noises and you still have video on the screen, you can run a hard drive test utility. I usually use Hitachi’s drive fitness test. This test is reliable and easy to use.
Situation 6.
The laptop boots into Windows ans works for a while, but after that it shuts down by itself without any reason or warning. You restart the laptop but the same problem appears again
Most likely it’s a heat related issue. Listen for the cooling fan, make sure it works.
Also this problem might appear because of a faulty memory module, try some tips from the situation 2.
The laptop still boots ans you still can see the screen, so you can run the memory test. I usually use Memtest86+. Run the memory test and if it fails, replace the faulty module.
Situation 6
The laptop starts normally but video on the screen has lines, some strange characters or other defects
It could indicate a problem with the laptop LCD screen, video cable, graphics card or motherboard. Here’s my previous post witch covers troubleshooting bad images on the screen in more details.
Related post: How to troubleshoot dead laptops.

Toshiba Satellite A60 and A65 problems

Let’s talk about problems typical for Toshiba Satellite A60 and A65 notebooks. Do you own one of these laptops? Is it working fine for you?
Here are some typical issues I’ve notices with this model.
1. First of all – overheating
Does your laptop shuts down without any reason when you ran CPU intensive programs? If yes, then most likely it happens because the laptop overheats. It happens because overtime the heatsink gets clogged with dust. A layer of dust collects between the cooling fan and the heat sink (dashed line on the picture) and heat produces by the processor gets trapped inside the laptop. As a result of that, the processor overheats and the laptop shuts down.

There are two different way to clean the heat sink and fan in these models:
– Buy a can of compressed air or find an air compressor and blow off the heat sink through the air intakes on the bottom of the laptop.
– Remove the keyboard and you’ll get an access to the cooling fan. Blow off dust from the fan and the heat sink.
In some cases the laptop overheats because of defective cooling fan. The fan should start working as soon as you power up the laptop. If the fan will not star, most likely it’s bad and must be replaced. You can find a new heat sink cooling fan for Satellite A60 and A65 notebooks by the following part number: V000042110.
2. Defective onboard memory
Here’s another common problem – bad onboard memory. This memory is integrated into the motherboard and if it goes bad you’ll have to replace the entire motherboard.
If your laptop starts with some weird characters or lines of dots on the screen, most likely you have a faulty onboard memory. If you test the laptop with an external monitor, you’ll see the same defective video on the external monitor too. You can test the onboard memory with Memtest86+ utility. Remove any external RAM modules and run the memory test. If the onboard memory fails, you’ll have to replace the motherboard.
The integrated memory module is located close by the memory extension slot, under the foil.

UPDATE: If you have bad memory, you should read this comment.
3. Last but not least – power jack issue.
With Satellite A60 and A65 notebooks this problem is not as common as with Satellite M30X, M35X, A70 and A75, but it’s still a problem. Overtime, the power jack might get loose and the positive pin stops making a good contact with the motherboard anymore. As a result, the laptop switches to the battery power even though the power adapter is still plugged in. Usually you can temporally fix the problem by adjusting the power adapter plug on the back of the laptop, but after some time the problem reappears.
In this case you’ll have to disassemble the laptop, remove the motherboard and resolder the power jack.

Do you experience the same problems or you have another issue with your Satellite A60 or A65 notebook? Please share your experience.

Instructions for replacing laptop power jack yourself

Accessing hard drive using USB enclosure

If for some reason your notebook fails to boot and you need to access data on the hard drive (I assume there is nothing wrong with the hard drive itself), you can use an external USB enclosure. This method is very simple and could be very useful when you need an emergency access to your data on the hard drive.
First of all you’ll have to buy an external USB enclosure for notebook hard drives. These enclosures are inexpensive and usually you can buy them in any local computer store. You also can find a wide variety of external enclosures on the Internet. Make sure to buy a correct one, enclosures for ATA and SATA hard drives are different (the connector inside the case will be different). Usually the enclosure includes the case and the USB cables.

Now remove the hard drive from the laptop. For this example I’m using an ATA hard drive.

Open up the enclosure case and connect the hard drive to the connector inside. After that insert the hard drive into the case.

After everything is assembled, you are ready to connect this device to any working computer (notebook or PC). The enclosure cable usually has two USB connectors on one end, make sure both of them are connected to the computer. You don’t need any external power supply for the enclosure because the hard drive gets power through USB ports. If the computer you are connecting the enclosure to runs Windows 2000 or higher, you will not need any device drivers. As soon as you connect the enclosure to the computer, the external hard drive should be detected and recognized automatically. After that the external hard drive will appear in My Computer and you can access it as any other hard drive in the computer.

If you are getting “Access denied” message when you are trying to access your files on the hard drive, you’ll have to take ownership of a file or folder.
My previous post explains how to connect a notebook hard drive to a desktop PC via IDE hard drive adapter.

A key fell off the keyboard. Fixing the problem.

One or more keys fell off the laptop keyboard and you are not sure how to put them back? Don’t worry, most likely you can fix the keyboard and it’s not necessary to buy a new one. There is no universal repair guide because all keyboards are different. Here’s what I usually do in this case.
Situation 1. The key cap and key retainer fell off the keyboard and you cannot figure out how to assemble them back.



ReplacementLaptopKeys.com has the right Laptop Key Replacement for you.
Carefully remove the cap from any other working key so the key retainer stays connected to the keyboard.

Take a closer look at the key retainer, it’s connected to the keyboard at four different points.

Assemble the disconnected retainer the same way as one on the keyboard and put it back in place.

Put the key cap on the retainer and snap the cap back in place.

Situation 2. The key fell off the keyboard and you lost the cap or the retainer. In this case you can purchase a single key on the internet, just search for it. (Search examples: “Dell keyboard key”, “Toshiba keyboard key”, “HP keyboard key”, etc… )
After you found a new key, put it back in place the same way as I described in the situation 1.
Installing the space bar key.
The space bar key is connected to the keyboard a little bit differently then any other key.

There is a metal retainer connected to the space bar key (on some keyboard models). Separate the retainer from the space bar key with a flat head screwdriver.

Install the retainer back in place as it shown on the picture. You have to engage the retainer with the small hooks on the keyboard.

Put the space bar key back in place and gently press on it with fingers until it snaps back in place.

That’s it. The space bar key is installed back in place and should work as before.
Here’s another technique you can use to fix a broken keyboard key.
As you see on the picture below the keyboard is missing the U key. The key cap, retainer and even silicone membrane were lost. Let’s see if it’s possible to temporarily fix the U key without buying any spare parts.
Personally, I cannot use keyboard without U key but I can live without a key located on the side from the right ALT – the “Right clicker” key. In the following guide I will remove one key I never use and install it in the place of missing U.

Carefully remove the key cap with your fingers.

Remove the retainer. The retainer has two pieces connected to each other. If one piece got disconnected from the other, connect them back together.

The silicon membrane is glued to the keyboard. Very very slowly separate the membrane from the keyboard with a sharp knife. While creating this disassembly guide I damaged one membrane because I wasn’t careful enough.
Again, you have to be very careful removing the membrane.
If you damage the membrane you’ll end up with two broken keys instead of just one.

The silicon membrane has been removed.

Now apply some superglue on the bottom edge of the membrane, just enough to keep the membrane in the place.

Carefully place the membrane in the center of the U. Make sure the membrane is positioned correctly. Wait until the glue cures.

Install the retainer.

Position the key cap above the retainer. Gently press on the key cap until it clips in and connects to the retainer.

Now you can use the U key again.

Troubleshooting. Why the key will not clip on.
 
Turn the key upside down and take a closer look at the locking clips. It’s possible that one of the clips is damaged and because of that the key will not clip on the retainer. If that’s the case, you’ll have to purchase a new key.

On the next picture you can see that one of the clips is missing, it’s broken. This key will not stay connected to the retainer either. If that’s the case, you’ll have to purchase a new key.

It’s possible that the key is fine, but the retainer itself is broken. On the next picture you can see that one of the tips is missing on the retainer. The left tip is OK, but the right one is missing. If that’s the case, you’ll have to purchase a new retainer.

Here’s one more picture. In this case two parts of the retainer will not stay connected to each other. It happens because one of the tips is broken. The left tip is OK, but the right one is missing. If that’s the case, you’ll have to purchase a new retainer.