What is a white screen? It may not be well understood by many people.LCD liquid crystal screenAfter booting, the LCD screen becomes all white (white screen) fault, this is the boot LCD white screen fault phenomenon. LCD LCD screen white screen failure is generally LCD screen failure, the following to see the failure of the LCD screen white screen as well as repair ideas.
Failure causes of LCD white screen:
a. Wrong principle, wrong layout. wrong connection of IM0, IM3, left and right connections reversed, one of the leads wrong, wrong connection of power cord, ground wire not connected, etc.100% bad
b. Test rack connection error. IM0, IM3 connection error, data cable connection error, power cable connection error, ground cable not connected, etc. 100% bad.
c. Program error. 8 to 16 selection error, high, low 8 bit selection error (P0, P2 ports), initialization code error, insufficient time for program reset, function not called.100% is not good.
d. Poor contact with gold finger. Soldering, with tin clips, virtual soldering
e. Poor connector contact.
F.Soldering FPC, gold finger breakage
g. Virtual soldering of components on FPC (virtual soldering of voltage doubling capacitors, virtual soldering of crystal resistors), component damage (diode breakage) crystal resistor is too small.
h. Insertion and removal of connectors, metal breakage of wire at reinforcement (partial breakage of wire can be observed under a microscope).
i.Poor FPC compression joints. Foreign matter somewhere in the small gold finger, ACF conductive particles, crimping temperature, pressure during crimping, etc. Causes one or more gold fingers to break or contact resistance to be too high.
j. Poor IC crimping performance. Abnormal contamination on the IC pads, conductive particles on the ACF, crimping temperature, pressure, etc. result in poor contact (open circuit) or excessive contact resistance on one or more of the key pads.
LCD white screen repair ideas
1, first disassemble the LCD screen shell, and then check whether the screen line interface is loose or not connected. After checking the screen line connection is normal.
2, then open the LCD LCD power switch, and then use a multimeter to measure the screen line interface supply voltage is normal. If the supply voltage is normal, go to step 5; if not normal, then check the screen line output near the insurance resistor or insurance inductor is open or damaged. If damaged, replace the damaged components.
3, if the screen line output near the insurance resistor or insurance inductor is normal, and then check the power supply for the LCD LCD DC-DC voltage conversion circuit output voltage is normal. If the output voltage is not normal, check the power supply circuit of the insurance resistor, PWM controller, switching tube, inductor coil, filter capacitors and other components, and then replace the damaged components.
If the output voltage of the DC-DC voltage conversion circuit is normal, there are damaged components such as capacitors between the output of the DC-DC voltage conversion circuit and the interface of the screen cable, check and replace the damaged components.
5, if the screen line interface supply voltage is normal, then check the LCD panel driver circuit in the timing signal, drive signal is normal. If not normal, respectively, check the output signal of the chip that generates this signal, the input signal and supply voltage, so as to determine whether the driver chip is damaged. If damaged, replace it.
Through the above understanding, the LCD LCD screen white screen fault causes and repair ideas is not a preliminary understanding, LCD screen on white screen repair up is not as easy as the LCD screen black screen, you need to master some of the knowledge about the circuit of the LCD LCD screen, the most insured method is to ask a professional to help you, find out the cause of the solution. So in the purchase of LCD LCD screen is not only look at the appearance, to find a quality LCD screen manufacturers, such as: ICP DAS - more than 10 years focus on LCD, touch screen, is your trustworthy LCD manufacturers.