how to diagnose a faulty laptop screen

Modern laptops are prone to LCD problems but it’s not always that easy to diagnose the fault. When your laptop screen goes blank it’s normal to automatically assume the laptop screen is at fault. However, it’s not always that simple. So, before you head to your nearest laptop screen repair shop you need to diagnose the fault by following the simple steps before.

Being able to diagnose your own laptop problem can help determine whether it’s worth fixing. Also, you will know if the computer repair engineer is being honest with you.

Before, I start with the checks let me explain the possible faults you might encounter when it comes to laptop screens:

  1. LCD screens can easily be damaged
  2. The LCD backlight stops working
  3. The pixels start to die and the image is no longer clear
  4. The laptop graphics cards fail
  5. Loose connections


Now let’s look at the different options we have open to us in order to carry out some simple check to help us determine what the problem is.


Check 1: Does Your Laptop Screen Show Signs Of Damage?

The easiest and most obvious way to tell if your laptop screen is damaged is to look for physical damage. Most laptop screens stop working due to some form of damage from being stepped on to forgetting to take your pen from the keyboard before closing the lid down.

With such damage you will normally have a blob of different colours or one side of the screen will be black, colours, discoloured or just looking worse for ware.

If this is the case then – you can either replace the laptop screen yourself or head over to your nearest laptop screen repair shop.

However, if this is not the case then we need to look deeper into the problem.


Check 2: If your laptop screen flickering?

A flickering screen is very common laptop problem especially if you are using Window 10. I have experienced a number of similar problems and all have been related back to Windows updates. If you do have a flickering screen problem then the first step is to start your windows in safe mode.

Once in the safe mode head over to your Device manager and click on your graphics driver and do an update. If the problem continues then remove the driver and restart your laptop. This should fix the issue.

However, if the issue is not fixed please continue with the rest of the checks.

Check 3: Does Your Laptop Power UP?

This is especially important to check if you have a completely black screen. It might be that your laptop powers up for few seconds and then goes off. This would indicate a totally different problem which has no relation to your laptop screen.

However, if your laptop stays on and the hard drive light is blinking – then we can be assured to some extent that the laptop is running through its start-up processes. This is normally a good sign as we can almost always rule out the motherboard fault.


Check 4: Check your screen brightness?

how to diagnose a faulty laptop screen

Actually, this is the simplest check but the one which is almost always missed. I have years of experience in laptop screen diagnoses and replacements. However, most recently I went to a job in Manchester where the laptop would power up but the screen was black.

I did my normal check and concluded the issue was with the LCD backlight and proceed to replace the screen. On completing the job the problem was back. After spending another 2 hours looking at different options, I decided to try the most basic one: which was function key+brightness. To my surprise, the laptop screen came to life!

You live and learn everyday! Sometimes we miss the simplest of solutions just because we think it’s a bigger problem.


Check 5: Have you tried a hard reset?

From time to time laptops computers do break without any reason. Yet, when you do a hard reset they suddenly power up like nothing happened before. It’s hard to explain this crazy behaviour. But if it does work for you then be very happy as it’s the easiest and cheapest option to get your laptop working.

In order to carry out the hard reset please follow these simple instructions:


  1. Turn your laptop off all lights off. Make sure it’s not in the sleep mode with flashing power light.
  2. Unlock and remove the laptop battery
  3. Unplug the charger from the laptop and not just the wall.
  4. Press the power button for around 30 seconds. This will empty all the laptop components of any energy.
  5. Reverse the process plug in the battery, charger and power up.


Are you in luck? If yes this is great news. However, if the problem persists please keep reading.


Check 6: Does your laptop screen respond to light?

It’s very common for laptop screen backlights to go. This is the light which shines in the back of the LCD screen to light up the image which you can see. Therefore, when the backlight fails on your laptop LCD screen you will not be able to see anything.

The best way to check for this is to shine a torch on your LCD screen. You can use any type of torch for this test. I personally always use my android phone as it’s the easiest option for me.

If the screen comes to life once you shine the light onto it then we can be sure the problem is with the backlight. However, this is not to say it’s your screen backlight tube which is the problem. The actual problem can be related to your motherboard.

If at this point you are positive the issue is with your LCD backlight, then a visit to your local laptop screen repair shop is a good option. The laptop repair engineer with a look into the problem further and decide if the issues are with your screen or the actual graphics card on your laptop’s motherboard.

If you are no wiser to what the problem is at this point then we need to keep doing further checks.


Check 7:  Is Your Laptop Memory Creating the problem?

This is a little bit more of a technical check as you will need access to a screwdriver and some knowledge of the memory chips.

As with any electrical devices when opening them up we need to make sure the device is off and the battery and power supply have been removed. Once you have done this the next step is to turn your laptop over and find the memory access cover. It normally has 1 or 2 screws holding in place.

Unscrew the screws and pop the cover open. The easiest option is to remove the chip and reinsert. Sometimes the dust builds up and stops the connection from working correctly. If you have two memory chips in your laptop. Then you can remove one.

Once you have done this plug in the charger and power the laptop up. If you get a positive result then you will have some idea where the problem is at this point i.e. your memory.

But if the problems continue it’s time to move onto the next check.


Check 8: Does your laptop work on an external screen?

Most modern laptops come with either the VGA or HDMI output connections. For this check, you will need access to either a TV with VGA or HDMI ports or a standard computer screen. It makes no difference which option you take.

The aim of this check is to see if your laptop will display anything on the external screen. If the laptop does show signs of life on the external monitor then we can be positive the issue is with your laptop screen.

However, if nothing shows then we are in trouble.

At this point, we can be assured the issue is not with the laptop screen. As all the checks point towards the mainboard or the onboard graphics card. Unless you are very good with a multimeter and a soldering iron then this is a job for computer repair engineer. The laptop needs to be taken apart and motherboard components tested. The other option is to replace the entire motherboard as this might be the cheaper option depending on your laptop model.

If you have found this article helpful please feel free to share it and help others.


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