How to fix vertical lines on a screen of a Dell notebook
Complete Dell Inspiron 9300 laptop disassembly. Are lines on the screen fixable?
I recently tried to troubleshoot a Dell Inspiron 9300 that has white vertical lines on the display. But before I opened up the machine, I tried to make sure that the vertical lines is only present in the lcd screen monitor and not on an external monitor. The purpose of this test is to determine whether the GPU or graphical processor unit is functioning normally. I say this because, basing from my experience, most display issues such a white display, all-black display, pixelated or distorted display can be contributed to a defective video chip or GPU. So I connected the machine to an external 19″ lcd monitor and learned that those white vertical lines do not show on the external screen. But since the external monitor did not have any lines on it, then I can say that the video chip or GPU is working properly.
So at this point, I presume the lcd screen is defective. But as I knew it, there are other components in between the lcd screen and the system board or motherboard that interconnect to each other and that can cause incorrect display on the monitor. One can be the video connector. The other can be the inverter board. I went ahead and opened the bezel by the front plastic cover of the lcd assembly by removing the 8 caps and screws, that secure the bezel to the back lid using a Philips screwdriver. Then I removed the screws on each side-brackets; and I carefully laid the lcd screen face down on top of the keyboard. I can now see the video connector and the inverter board. I removed the tape that holds the video connector and the sockat and then disconnect the video connector and immediately reset to the socket. After that, I powered the machine. At this time the display still has white vertical lines. I’m pretty sure that the inverter board does not have anything to do with a vertical line issue. Because all it does is to power the light bulb or CCFL (cold cathod flourescent lamp) inside the lcd screen. So now I’m down to just one component, which is the lcd screen itself. But what would cause it to have vertical lines on it. As I tried to tap the back upper portion where the electronic board is located, while the machine is one, I noticed the 2 or 3 of the lines are disappearing. Meaning some loose connection is present on the back of the screen. So I can now conclude and tell my customer that she has to change her lcd screen with model and p/n Philips LP171U1 17″ WUXGA.
The following video is the actual work I did with the Dell Inspiron 9300 with white vertical lines on the screen. ( later on in the video, I decided to open the whole machine so that I can show off how to remove and replace the other parts of a Dell Inspiron 9300 including the chassis (top and bottom), optical drive, wireless card, cpu and cpu fan; until I get to the motherboard)
Now, let’s go farther as to why the lcd screen has those white vertical lines. The quick answer is the tab connection failure. A tab is that flat connector that is attached or that is connected to the transparent electrode layer of the video driver circuit board of an lcd screen. (Please see the following illustrator I copied from a website www.acffilm.com
That was the reason why the white vertical lines on the screen disappeared when I put pressure on the back of the lcd screen where the tabs where located. But you may ask, can this be fix? – Yes, it can, but it can only be performed by qualified tab bonding specialist or company. It is done using a tabbing machine. Usually, for tab bonding, they use heat to remove the tab from the transparent layer, then they apply a conductive paste before reattaching or bonding the tab by heating the area connected to the electrode layer.
In my experience, I resorted to buy a new lcd screen than sending it to the tab bonding companies, because it may cost more to fix it that to buy a new screen. I usually get one or two from the machines that I fixed. And I find it impractical to send back and forth to those companies. Well, if you are in the business of lcd repair, where you have several lcd screens to be repaired with display issues, then a tab bonding company service can be a good solution, or better yet to buy a tabbing machine.