Have you ever experience that the laptop screen is so dark you can barely see anything. It will now be fine if you attach to the desktop monitor, but the laptop screen stays dark? The way to sove it?
What's the meaning of laptop LCD screen brightness is not enough? We call this phenomenon as 'dark screen' means how the ignition coil failed provide electricity to the lamp on the LCD lcd monitor.
People who use laptop regularly knows that genuine effort . a small lamp for bright to LCD screen, so people mistakenly belief that the lamp burned when the screen become dark. Let's have a detailed reason for screen dark failure.
Points caused screen dark failure is four:
1, Fluorescent tubes disconnected (Generally, laptop lamp won't be destroyed by the high-voltage in the normal use, the reason of lamp off is mainly due to laptop fell to the ground and lamp strikes grave.)
2, Ignition coil no power supply to the lamp (The motherboard with 3-4 group of voltage for the ignition coil, ignition coil through the chip for the transformer to the lamp post, chip aging or over-current burn without electricity production.)
3, Motherboard no strength to the ignition coil (There are 3-4 voltages group in the motherboard to the ignition coil, and two groups-chip output voltage to high voltage board, chip aging or over-current burn without electricity output)
4, Cable disconnect (There is an attached cable between the motherboard and the ignition coil, in a long time moving LCD screen cable disconnected, resulting in no main electricity supply to the ignition coil.)
These four points are the major reasons caused by the dark screen one three are more emerged, the fourth point of the opportunities arise is relatively small, because rest and memory connect line is also included with a special involving shield is engrossed in it and a small number appear to get in touch line disconnected phenomena. Professional maintenance staff for the detection of each process are essential.
The following is often a special case in the testing process:
The problem descrition: People rebooted laptop computer after laptop standby, and the laptop screen became dark, entered WINDOWS must depend on the shining lights previously outdoors, then suspected to have no electricity to supply of high-voltage lamp. The very thing to do is connecting the external PC monitor to see are going to can enter WINDOWS properly. This step is very vital that determine whether you'll find other problems of hardware and tools. Generally, professional maintenance center will test hardware and software to ensure the phase-side will not really conflict of benefit.
After the failure was determined, we are able to start to dismantle the screen frame, in general, round the screen are 4-6 screws hidden, so that we must remove the screws first, and laid the back frame out. The frame will obtain a serious crack if ever the screws stay. When possible find that there is a white plastic insulation, the above is written note: CAUTION: HIGH Voltage.
This is a high-voltage plate, could find the high-voltage structure while demolition of plastic insulation. The motherboard has four cable to connect high-voltage plate and along with chip distributing voltage to the coil, then light the lamp brighter.
First, we use the substitution to test lamp is disconnected, remove the lamp from the high-voltage plate and graded at a pre-prepared pontoon. If no reflection after boot, rule out the reason of lamp. The we test the motherboard supply the 3-4 group high voltage to the board, connect motherboard to the high voltage board and split to be able to use multimeter to run a test voltage.
We can see that the motherboard will finally be just using 5V voltage for the high-pressure plate, generally if the motherboard has problems, it may lead some consequences not good, so the steps of associated with testing each one are necessary.
There are two holes at guidelines of the host, it can crop up with a hard object, then the connector links motherboard and high voltage board come in our eyes. We still use the multimerer to test by means of port location of power supply is normal, strange things happened at this time, the interface of motherboard voltage id normal but the other side with the voltage is already gone. Is it the problem of cable. We take out the axis which covered the screen observe the location of line has been turning roll up into a ball, initially suspected for due to a hard swing-screen product line disconnected. We split the cable contrary to the motherboard out of measurements at each side to see connected or not.
After finding really don't . and then we recruited three cables to disconnect part of the extension of welding well, and employ shielded wire to wrap in then boot. Fluorescent tubes and displays finally normal, although implies of detection along with the process sequence spend a lot of time of engineers. Essentially the most suffering is consumer if the unprofessional maintenance center neglected to get cable while on the test part belonging to the chaotic demolition motherboard testing, and set up with more questions if not the attached anti-static equipment.