Updated date:

Troubleshoot Display Related Faults in Your Laptop

Alfred is a long-time teacher and computer enthusiast who works with and troubleshoots a wide range of computing devices.

Dead laptop screens

Dead laptop screens

You do not necessarily have to panic when you wake one morning and your laptop display has gone black. A number of beep codes and visual signals should guide you through diagnosing and troubleshooting it.

For starters, a blank laptop screen may point to a faulty motherboard, a dim display may be symptomatic of a faulty inverter or LCD/LED screen.

Also depending on the model and brand of laptop, you can also use the light codes usually next to the power-on light to read into the status of the laptop. For example, activity or inactivity on the disk drive light should indicate success or failure in boot up.

Third, beep codes can also guide you through troubleshooting the blank screen. A single beep should signal normal startup whereas more than one, accompanied by no display on the screen, should signal component failure.

1. A Blank/Black Screen

A totally blank screen following power-up of the laptop is symptomatic of:

  • Faulty memory module/S (RAM)
  • Loose fiber connection either on the laptop screen or motherboard
  • Faulty screen
  • Faulty display chip
  • Faulty motherboard or microprocessor chip

In the case of no display, start by connecting your laptop to an external monitor via the VGA or other display port. If all is fine, There should be display on the external monitor. Try restarting the laptop with the signal cable attached, if the external monitor does not identify the laptop immediately.

If there is no display on the external monitor even when you restart the laptop, proceed and check the memory modules just to be sure they are fine. You can do this by opening the rear of your laptop and reseating the RAM sticks or swapping them to see if there is a positive response. Some laptop brands have additional RAM slots located below the keyboard. You may need to dig around to locate all RAM modules and slots.

Alternatively, use Memtest to find out the reliability of the chips using a separate laptop.

Just incase of garbled images, check to ensure the laptop video cable (fiber) is  firmly connected both on the motherboard and LEC/LED screen

Just incase of garbled images, check to ensure the laptop video cable (fiber) is firmly connected both on the motherboard and LEC/LED screen

If RAM is fine, however, and the external monitor displays well, then the fault should be elsewhere else.

You may need to open up the laptop and check the LCD/LED fiber connections on the motherboard or the screen itself. Much as these connections are usually firm, contraction/expansion, age and repeated closing/opening of the laptop screen can just about make it snap out of position. For example, a little distention of the fiber can leave laptop display garbled and unreadable. Total disconnection is bad enough.

If the fiber is firmly connected, you may need the help of the computer technician to diagnose the health of your LC/LED screen, and maybe try out other screens. This should not be done at home unless you know what you are doing and have corresponding spare LCDs/LEDs in the house.

Another component that is prone to failure is the graphics processing unit (GPU) chip. This chip which is located close to the microprocessor and controls screen display can fail due to overheating. The infamous nVidia graphics chip from AMD is known to fail especially after a few years of heavy graphics use.

In spite of GPU failure, you can sometimes view information on the LCD/LED or external screen albeit garbled images.

Most times, however, a faulty GPU will not allow you to view information on either screen. You will know this when everything else, including Windows, seem to be running smoothly in the background.

The infamous nVIDIA GPU heats up over time and the laptop screen may fail to display as a result

The infamous nVIDIA GPU heats up over time and the laptop screen may fail to display as a result

Fixing the graphics chip is a tricky business because it involves blowing hot air onto the faulty chip using a heat-gun. This kind of repair does not guarantee permanent chip repair. You will actually get less than just a few months after the repair.

If all the above solution does not yield results, either the motherboard or microprocessor in your laptop could be at fault. At this stage, motherboard or microprocessor replacement maybe the best solution and can be done by the tech guy next door.

If however, you have a compatible microprocessor at home and know what you are doing, try swapping it and see the results.

On the hand, motherboard replacement is a long shot and unless the laptop means a lot to you, it could be time to purchase a new computer.

2. Laptop Display is Dim

The dim display means the laptop is fine except it receives insufficient light to fire up the LCD/LED screen. A dim display is symptomatic of:

  • Faulty display inverter
  • Faulty backlight lamps
  • Brightness set too low

In case of dim display on the laptop screen, either the inverter or backlight lamp failure is to blame, but usually, the inverter has failed.

Backlight lamp failure rarely happens and when it does, complete replacement of the LCD/LED screen is the only option.

Replacement of backlight lamp inside the LCD can be a nasty experience since it involves ripping the LCD screen apart and toying around with tiny, delicate lamps.

A six inch long inverter board. Its failure will manifest in a faint/dim display on the laptop screen

A six inch long inverter board. Its failure will manifest in a faint/dim display on the laptop screen

On the other hand, replacement of the inverter for the LCD screen is more sensible than repairing it. It requires meticulous repair procedures which should not be done at home.

Lastly, make sure the brightness of your laptop is not set too low, especially if your laptop has adjustment knobs or buttons for brightness. A simple tap on a button can bring the screen back to normal.

The power light signal in an HP laptop. Missing HDD light signal at boot up should indicate some power up problem

The power light signal in an HP laptop. Missing HDD light signal at boot up should indicate some power up problem

3. A Broken LCD/LED Screen

Your laptop can also fall to the floor and leave the LCD/LED screen broken.

While some breakages may not be evident in a laptop that is turned off, the cracks on the screen will show the minute it is powered up.

Fortunately, LCD and LED repair should not be as complicated if you know how to open and thereafter assemble the LCD/LED back into the laptop lid.

An LCD screen is attached to the laptop motherboard through a video cable (fiber) which should only be disconnected at the top during replacement. At the base of the LCD screen is a twin power cable which is connected to the inverter, which is located just below the LCD.

An LED meanwhile uses only the video cable to connect to the motherboard and does not use the traditional inverter.

How To Replace The laptop Video Cable

© 2015 Alfred Amuno

Related Articles