Before you rush off to replace a malfunctioning LCD TV, it pays to check the inverter board. Replacing an inverter board costs significantly less than replacing the entire television and the process requires minimal technical expertise. Inverters put out a fairly high level of voltage to power and light up your LCD screen, with most inverters outputting in the 500- to 700-volt range. A faulty or damaged inverter board can cause image distortion, dim your screen or prevent it from turning on.
Turn your television on and shine a flashlight on the screen to look for an image. If you can see an image, then you likely have a bad inverter that needs replacement. The inverter board keeps the backlight of the television on.
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Turn off your television and remove the power supply from the wall. Once you unplug the television, wait until the back of the television cools down and no longer feels warm to the touch.
Place the anti-static wrist band on your wrist and remove the back panel on the television. On some televisions, you may find the panel on the front of the television. Use a Philips screwdriver to remove the screws and then use a flat-head screwdriver to gently remove the panel to access the electronics.
Look for a rectangular metal casing. LCD TVs have two inverter boards -- a slave and a master. You can find the boards on either side of the metal casing. You can access the boards without having to remove the metal casing, but you should remove them to make testing easier. Use a Philips screwdriver to remove the screws and pull the casing off the board.
Set your multimeter to "DC Mode" and locate the first pin for one of the LCD inverters. Place the red probe on Pin 1 and place the black probe on any metal screw inside the casing to ground the multimeter and prevent shorting the inverter.
Power on your television. You can have someone else help you with this process so that you don't lose contact with the pin and the screw on the inverter board. Take note of the reading from the multimeter.
Power off the television and test the other inverter using the same process. Compare the results of the two inverters. If you get no readings, you need to replace both inverters. If you get significantly different readings, replace the inverter with the lower value. If both the readings come back with similar values, you may need to replace the backlight on your television.
Things You'll Need
Anti-static wrist band
The multimeter must have a frequency detection rating of at least 50 Khz to test your LCD Inverter.
LCD inverter boards can provide a significant amount of power. Consider wearing plastic gloves to reduce the possibility of electrocuting yourself. If you don't have experience working with electronics, take your television into a repair shop for a professional evaluation.