Urgent!! For LCD display maintenance technical information, lectures with. Answer well, add 100 points. Do not add is dog!!!
Author:Lu Chanjuan Time:2021-07-21 11:23 Browse(917)
Two pieces of LCD maintenance
Two pieces of LCD maintenance.
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LCD for the majority of players is no longer as unattainable as before.

Urgent!! For LCD display maintenance technical information, lectures with. Answer well, add 100 points. Do not add is dog!!!

its price has been basically acceptable.
you have seen a lot of troubleshooting of CRT.
here, the author introduces the maintenance examples of "noble" LCD.
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example 1: a second-hand nec15 inch LCD
the fault phenomenon of the display is that the power indicator is on, but there is no display on the screen.
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fault analysis.
the power indicator of the LCD is on.
at least it indicates that the power supply of the display is good.
but there is no display on the screen.
the most common situation is between the LCD control module and the segment electrode of the LCD panel, There is a fault of poor contact.
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troubleshooting.
disassemble the shell of the display.
you can see the circuit boards of the control circuit and the power circuit.
after removing the circuit board, the X and Y electrodes of the display panel are exposed to lead out the data lines (X electrode is referred to as back electrode.
Y electrode is referred to as segment electrode), The detection can be started.
we know that the segment electrode of LCD and the output driving electrode of display module are connected by conductive rubber.
this is different from our common calculators The connection mode of the stroke display screen of the electronic watch is the same.
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the simple way to check the display screen is to use an ordinary wire.
peel off a small part of the insulating skin at one end of one of the wires, and then wind the other end of the wire around the power line of the desk lamp (other household appliances can also), so that a weak AC voltage will be induced in the wire, Although the internal resistance of the induced voltage is very large,And it only has 50 Hz AC induced electromotive force, which has no effect on general household appliances, but it is just suitable for driving LCD devices.
hold the back electrode lead of LCD panel with your left hand or touch it with metal probe (the back electrodes of each row of pixels are connected together).
then hold the wire with induced voltage with your right hand, Contact each section of electrode (i.e. Y electrode) with bare wire ends respectively. As long as the pixel corresponding to each section of electrode reacts, it can be judged that the display screen is good.
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the author found that.
when the wire contacts each section of electrode, The liquid crystal displays all react.
it is concluded that the fault occurred on the conductive rubber.
it may be caused by poor contact.
the author cleaned the conductive rubber with high-purity anhydrous alcohol and put it back in place.
then the components were restored, and the power on test display can display normally, Troubleshooting.
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maintenance summary.
why not use the resistance block of the multimeter to provide the driving voltage of the segment electrode? Because the resistance block of the multimeter provides 9V ~ 15V DC voltage.
the electrode of the probe contact section for a long time will damage the LCD panel, and the method mentioned above provides weak AC current, which is relatively safe (this depends on the nature of the LCD panel, However, it should be noted that when using this method to test.
it is possible that the pixels corresponding to the electrodes in the section where the wire probe does not contact on the panel also react, which is caused by the induced voltage on the suspended electrode, which belongs to the normal situation.
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the components of the LCD are relatively fragile.
be careful when disassembling, and pay attention to anti-static, At the same time, it should be noted that there is also high voltage in the LCD display.
the LCD display has high voltageIn addition, the removal of LCD display is only limited to the removal of circuit board.
if you remove the LCD panel, the display will be scrapped, This point must be paid attention to.
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example 2: a 15 inch LCD screen is disordered and unstable.
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fault analysis.
refer to the method in the above example and test after processing.
the fault is still found.
but when I accidentally move a bass speaker on the computer desk.
I found that the display on the LCD screen also changes, The author immediately cut off the power supply of the speaker, and removed the speaker from the computer. At this time, the display suddenly returned to normal display, and the fault was cured.
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maintenance summary.
some users mistakenly believe that the LCD is not afraid of magnetic field interference because of shadow mask and electromagnetic deflection system, as CRT, In fact, if the LCD often works in the magnetic field, it will also affect its normal operation (take apart the LCD, you will know that a good LCD control circuit board has a layer of metal magnetic shield).
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in fact, the LCD often works in the magnetic field, which will also affect its normal operation
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