Diagnosing common LCD problems
If you have a laptop or an external flatpanel monitor, chances are you’ve run into some problems with the LCD. If you haven’t yet, you probably will. LCD problems are some of the most common laptop complaints next to hard drive crashes and loose power connectors. Cracked LCDs, lines on LCDs, plasma effect, dim LCDs, dead pixels, backlight problems, and flickering LCDs are quite common.

Here are some simple tests to determine what’s wrong with your display and estimate the cost and difficulty involved in fixing it. This is not meant to be repair advice, so do not attempt to service your laptop if you don’t know what you’re doing… and if you’re reading this, you probably don’t. Do not disassemble your laptop if the battery is in or it is plugged into a power source.

Cracked LCD
Not much to test here, you’re going to need to replace your LCD. Either that, or buy an external flatpanel.

Lines on LCD
This is generally due to a broken LCD or internal LCD video cable. Sometimes if you drop your laptop hard, it can damage the LCD (and the hard drive if it’s on). Plug the laptop into an external monitor or LCD tv. Does the picture have lines? If not, you either have an LCD cable or LCD problem. If you see lines on the external monitor (assuming the external works fine), you most likely have a graphics card problem.

Plasma, oozing, octopus ink, growing plume
More than likely, your LCD is damaged and needs to be replaced. This is usually caused by a physical malfunction of the glass sandwich inside the LCD. As with the above test, check to see whether or not you get a clean picture on an external monitor. If you do, it’s time for a new LCD.

Dead, stuck, hot, or otherwise funky-looking pixels
These can be caused by manufacturing defects which cause transistors to die or stop responding inside your LCD. Sometimes you can fix a dead pixel, but you can also make the problem worse if you’re not careful. A safe bet is to try to fix the problem with software. Programs such as UDPixel and JScreenFix can try to diagnose dead, hot, or stuck pixels and even attempt to fix them. If these don’t work, as a last resort, you can try to gently press the affected area with an eraser to try to coax oil into or out of the pixel layers. Again, this is not guaranteed to work, and might make the problem worse, so be careful here.

Dim display
This could be due to two common problems: inverter or backlight failure. An inverter conditions power for the LCD, and generally sits near the laptop hinges under the LCD case. Inverters are dangerous because they generally run between 4-7 amps of current. 1 amp will easily kill you so don’t mess with these if you don’t know what you’re doing. If the screen is ever bright, chances are your inverter is fine. Backlights are difficult and dangerous to replace, so don’t try unless you know how. Most backlights are fragile and contain mercury, which is a carcinogen.

No display
If you get no display at all, check it with a flashlight. Hold it at different angles to the screen. If you really can’t see anything, try to plug it into an external monitor. If you get a clean picture, a bunch of things could be wrong. You could have a loose cable if you drop your laptop a lot. The cable could be pinched in the hinges and severed. Rarely do you get a complete failure of the LCD, but it’s possible.

Display works while booting, but stops working at some point
You’ve probably got a software issue. Time to check the drivers and check for viruses.

Display scrambles over time
This is generally caused by an memory problems or an overheating video chip. If memory is the problem, you can try to remove one or two modules of RAM from the bottom of the laptop, usually behind a panel. If this fixes the problem, time for a new stick of RAM. If heat is the problem, there are usually two causes. Either the video processor is overheating, or the entire laptop is overheating. You will need to have the laptop taken apart to clean out dust, test all the fans, and check the thermal compound under the heat sinks.

Need more help? Send us an email at help@pcxmedics.com, or use our contact form.