Phenomenon: white view on full screen after turning on LCD.
Analysis: it may be caused by drive IC of panel, power supplying circuit of panel, bad connection between screen and wire, control IC of main board, etc. White screen also shows that the back light and high pressure circuit work well and the panel can’t get drive signal. High pressure circuit is out of control, i.e., switch signal is out of control. Switch signal sent from microprocessor of main board is usually controlled by several triodes, thus it’s much possible that the triodes are destroyed.
- Take apart the LCD shell, check if the connection between screen and wire is loosening or break/disconnection. Result: good.
- Turn on power supply. Use multimeter to check if the power supply voltage works well. If ok, go directly to step 5. If not, check the thermo-sensitive resistor and inductance beside the output terminal of screen and wire. If it’s a open circuit or damage, change a good one.
- If the thermo-sensitive resistor and inductance works well, check if the output terminal voltage is good. The voltage of DC-DC voltage conversion circuit supplies power to LCD display. If the voltage is abnormal, check the thermo-sensitive resistor, PWM controller, switching, inductance coil and filter capacitor and change the damaged componenet.
- If the output terminal voltage is good, that will be much possible that there’s a damaged capacitor between DC-DC circuit terminal and display & wire connection. Change a good component.
- If the voltage of display & wire connection is good, check if the time series signal and driving signal (driving circuit) is good. If not, check separately the output terminal signal, input terminal signal and power supply voltage of relative chips. All these are for checking if the chip is good.
Of course the best way is to ask professional man for help.