How to protect and repair LCD backlight (Part 2)

When the voltage of the lamp current feedback terminal IS is lower than 0.4V, the comparator in the chip will consider the lamp to be open (the positive and negative gates are reversed) and enter the lamp open protection. When this pin is higher than 2V, the internal comparator of the chip will think that the lamp tube current is too large and the high-voltage transformer winding is short-circuited, and the over-current protection is entered. When the lamp high voltage feedback terminal VS is higher than 1.2V, it will be considered that the high voltage is too high and enter the overvoltage protection. For mobile phone LCD TVs, the lamp will turn off when it is turned on, or it will be turned off after flashing 3 times. Repair ideas-there may be a defective lamp; the high-voltage transformer of the backlight board is short-circuited; the lamp is overvoltage, overcurrent, or lamp Defective open circuit detection circuit; Defective backlight chip oscillation circuit, etc. At this time, first check the secondary line package of the high-voltage transformer, compare it with other line packages (resistance value), and find the bad high-voltage transformer. If it is normal, check the lamp when the lamp starts to flash after the screen is turned on, whether the lamp is not bright, the lamp is dark red, the two ends of the lamp are seriously black, and the lamp holder is virtually connected. If the lamp is normal, check the lamp Check whether there is any abnormality in the over-current and over-voltage detection circuit. If it is normal, it is necessary to detect abnormalities in the RC and transistors on the periphery of the backlight chip.
In the present growing world of emerging technology, the has demanding operation in various sectors like lcd screen factory, wholesale lcd screens, mobile touch screen spare parts and many other industries at cell phone lcd wholesale levels of manufacturing and designing.
Now you can enjoy mobile phone lcd screen wholesale with Kimeery (HK) Industrial Limited's latest collection of custom lcd screen mobile phone lcd display products. Do visit now, at Kimeery Phone LCD.
Many business owners and professionals use services like Kimeery (HK) Industrial Limited to stay on top of manufacturing industry, monitor products’ quality and keep an eye on competitors.
lcd screen factory mobile phone lcd display with wholesale lcd screens are used extensively in mobile touch screen spare parts.