LAPTOP Inverter Fault Detection Method

LCD panel for high voltage power supply to the lamp power supply, it will transform the high-frequency DC low-voltage power supply high voltage power supply to light the lamp, belonging to power conversion devices, easy to heat, it is easier bad. There are many customer's screen dark, and incredibly anxious, thinking that bad screen, or the host goes wrong, drugs everywhere, grasping side asked did not know that that is a small high-pressure plate is broken!


In fact, the high-pressure plate is a switching power supply, except in relation to the ordinary switching power supply, it's less post-rectification filtering part of the class, while the focus on high-frequency high-voltage transformation. It's low-voltage DC on the motherboard (in general, is more than V, or 5V) through the switch into a high-frequency alternating current chopper, and then high-frequency step-up transformer in order to achieve light lamp voltage.

Inverter power and signal from the motherboard, generally there are so Jigen line connected to the motherboard: power V +, the power to G, switch signal S, luminance signal F (and some not). When the computer starts, the power supply, switching signal S to start switching oscillator circuit, switch to work, transformer voltage boost lit lamp.

Visible, high-pressure board a bad device is just a few easy: oscillation circuit, switch, transformer.

However, in the maintenance process, we found that many screen dark phenomenon is not due to pressure plate itself, but others are due to damage to the motherboard connection, some motherboard itself is bad, can not give high-voltage power supply board.

Example:

1, Toshiba 3000 computer screen light when the dark. Lamp power and high-pressure plate does not match the high-voltage plate power is too small, start heating over-current protection.

2, Purple computer (there is a Twinhead, are the same manufacturer OEM), they can not machine, the computer thought it was a bad motherboard, and after testing, the final result for the high-pressure plate is broken. Replacement of high-pressure plate, over a period of time, failure to reproduce the high-pressure board has burned. Was originally due to high-voltage plate power is too small!

Therefore, high-pressure section of the LCD screen lamp failure and are closely linked, it may be caused by high-pressure lamp of the damage, is also possible that high-pressure section of the PWM, or ignition coil damage.