LCD Monitor Inverter Board | Input-Output Voltage for the CCFL Backlight Bulb

CCFL stands for Cold Cathode Fluorescent Lamp. Its function is to light up the LCD monitor screen when a high-frequency current is passed through it.

The power circuits of this lamp are present in the monitor's inverter board, also called the SMPS board. It is called the inverter because it converts low-voltage DC input to high-voltage AC output.

To light up the backlight, you need a 12V DC input. The SMPS board then converts it to a high-voltage AC output in the range of 800-1000 volts. This in turn powers the backlight bulb.

Source Website

SMPS Electronics - A to Z Inverter Board Circuits

SMPS Board with No Power - Short Circuit and Voltage Surge Can Cause SMPS Failure

SMPS stands for Switched Mode Power Supply. It is the essential power supply unit (PSU) in electronic devices ranging from laptops to printers, LCD monitors to camcorders and plasma televisions.

When you get a SMPS board with no power, check the fuse on the board. If it has blown to a dark color then clearly, there's no power flowing through it.

A direct short circuit or power surge can cause SMPS failure. In fact, it is one of the most common reasons for failure. Sometimes, you might also hear an audible whine with low output voltage when this happens.

To fix this problem, first glance through the rest of the components on the board to see if a simple fuse replacement will do the job. Sometimes, the varistor and other components may have been shorted too, so it is better to use an ohmmeter for testing.

Source Website

Switched Mode Power Supply Repair - Electronic Techniques & SMPS Repair Manuals