Screen shows strange colors

posted in: Screen, Troubleshooting | 101

The screen started showing strange or wrong colors. What could be wrong? I’ve been asked this question many times and today I’m addressing the issue.



In this post I explain some basic troubleshooting techniques in case if your screen started showing strange or incorrect colors.
You have to know how to disassemble your computer in order to use following troubleshooting techniques.

TEST WITH EXTERNAL MONITOR

The main troubleshooting step is testing the video output on an external monitor (or TV). You can connect your laptop to an external monitor using VGA cable, DVI cable, HDMI cable or S-Video cable, it depends on a type of connector you have.

Most models have a VGA connector, so it would be the most common way to connect.

Some laptops detect external monitor automatically and start showing image on both screens right from startup.
Other models can detect the monitor but display image only on one screen (internal or external). In this case you’ll have to switch video between internal and external using the Fn key and one of the F* keys in the top row of the keyboard. This combination varies for different brands, for example it’s Fn+F5 for Toshiba, Fn+F4 for HP, Fn+F8 for Dell, Fn+F7 Lenovo etc…

WHAT VIDEO ON EXTERNAL MONITOR CAN TELL?

If both, the internal screen and external monitor (or TV) show strange or incorrect colors or any other image distortion, this is the graphics card failure.

If only the internal screen shows bad video but external image appears to be normal (as in my example), the problem is somewhere inside the laptop display. This could be bad connection, bad LCD cable or bad LCD screen.

Let’s narrow down the problem one by one.

TRY RESEATING LCD CABLE CONNECTOR ON MOTHERBOARD

The screen receives data signal from the motherboard via LCD cable. If the LCD cable not making good connection with the motherboard, it might cause image or color distortion on the screen. Try reseating the LCD cable connector and see if it fixes the problem. Make sure the LCD cable connector plugged correctly.

In most laptops the LCD cable connector located under the keyboard bezel (aka keyboard cover). If it’s not there, most likely you’ll find it somewhere under the keyboard.

WIGGLE THE LCD CABLE

The LCD cable runs inside the display panel, under the screen. For this test it’s necessary to disassemble the display, so you can access the cable.

A pinched or damaged wire inside the cable also can cause color distortion.

Wiggle the cable while the laptop is running. If moving the cable affects image on the screen in any way (it starts shown different colors, lines, or image clears to normal, etc…) most likely the cable is defective and has to be replaced. Try replacing the cable.

On the other hand, if moving the cable doesn’t affect image at all, most likely the cable is good and you have a failed screen. In this case you’ll have to it with a new one.

APPLY SOME PRESSURE TO THE DISPLAY

Try applying some reasonable pressure to the top part of the display assembly. Squeeze it with your fingers.

If the screen starts showing different colors, lines, or clears to normal when you squeeze the top part of the display panel, most likely this is screen failure. In this case you’ll have to replace the screen.

Also, you might be interested in the following posts:

Troubleshooting backlight failure.
How to test screen inverter.
Bad video on the screen. What is wrong?
Fix video problems.



101 Responses

  1. I tried APPLYING PRESSURE ON THE TOP OF THE DISPLAY (exactly as the picture above) and IT WORKED! Thanks for this! :D

Leave a Reply