So, your computer monitor is really dark or faint, and changing the brightness (using the ‘Fn’ key, for example) isn’t working. Now what to do? Simple. If you have a multimeter with a KHz option, use that to test the inverter. A cheap multimeter will register the KHz differently; if your multimeter KHz option only goes up to 20KHz, you may get a ’1′ as the result. This means the reading was ‘off the charts’…too high for the cheap multimeter to register the proper KHz. If you are looking for a good multimeter, consider the Fluke 110 true RMS meter, as its KHz rating goes up to 50KHz. The reason we want to test the inverter first is because the cost of inverters is low, so we can rule the inverter defective or not before moving on to the pricey LCD or backlight repair.

Take your multimeter, and set it to the KHz notch on the dial. Now, with the computer on, put the multimeter tips close to where the inverter would be (usually towards the bottom of the LCD housing), about a half-inch apart.