Failure phenomenon: the beginning of the year a friend replaced a 15-inch LCD display, model is AOC LM-500, has been using the normal. But just six months, this LCD

Indicator that a fault occurs, specific performance: as long as the computer is started or restarted, it will approximate "Huaping failure phenomenon, gives the impression as if the high-frequency electromagnetic

Interference, as the writing on the screen is very blurry and jagged. Into Win98SE system occasionally this failure phenomenon but the duration is very short and does not

Too obvious, most of the time the screen display is normal.
 
Failure check: I first replace a graphics card and still find fault. Followed by a working 17-inch CRT flat screen monitors replace exclusion test and no

Similar failure.
 
LCD display fault principle: Digital Interface (DVI) was the best interface for LCD display. But the graphics card manufacturers because of cost considerations, the graphics on the general did not

A digital interface, and VGA interface is connected through the internal digital / analog converter circuit and graphics. This form of connection, although it solved the the signal matching problem, but are also with

Come susceptible to interference and distortion. The reason, mainly because the liquid crystal display clock frequency is difficult and the input analog signal of the clock frequency is maintained

Synchronization, especially in the analog synchronizing signal frequency changing, if the synchronizing circuit of a liquid crystal display, or with the graphics synchronizing signal connection

The transmission line short-circuit, poor contact and other issues, unable to adjust to the follow-up in order to maintain the necessary synchronization between, there will be the start encountered

Abnormalities, and enter the system and then display the normal strange fault phenomenon.
 
Accordingly, I determine the point of failure is likely in the liquid crystal display internal synchronization circuit, or the connection interface pins as well as the top of the transmission cable.
 
Troubleshooting: LCD monitors taking into account the internal synchronization control circuit are generally set within an integrated circuit, and is extremely unlikely IC damaged. In

I will check the focus on the adjustable connector pins, transmission cables, as well as synchronization circuit components above.
 
LCD display enclosure apart, exposing the internal connection cable, turned on and off with a digital multimeter check buzzer block-by-check the connection pins with the corresponding cable guide

Through the case, did not find any open circuit, short-circuit and physical connection issues. Next, along the line direction of the cable connection, the input control circuit of the printed circuit board unit found found

Two miniature semi-adjustable potentiometer is mounted on the side of the circuit block of the 14-pin package, a printed circuit board is marked as WR604 other is WR1201. Author

Preliminary judgment according to previous maintenance experience in CRT monitors, two miniature semi-adjustable potentiometer, is probably used to synchronize the fine-tuning, but in the end what a problem it?

In order to secure and reduce the the number of disassembly LCD shell, I use anhydrous alcohol to two-and-a-half adjustable potentiometer all the cleaning, wipe it again until the alcohol all volatile

After the LCD monitor housing recovery power test machine and found that although the fault has been reduced, but several times in a row during the boot process fault sometimes be repeated. Helpless and then a

The times apart the casing of the LCD display, using a mini-Phillips screwdriver WR604-clockwise to adjust a little shell, followed by recovery and once again energized test, the liquid crystal display

The display showed normal this point, troubleshooting.
 
Little adjustment can make the Custom LCD monitor to temporarily resume normal work, but with the use of time, I believe that the failure likely will be repeated. Therefore, the author

Consider the fundamental solution, or replacement of a semi-adjustable potentiometer. Unfortunately, this is a big deal than mung bean how many semi-adjustable potentiometer in ordinary electronic market is difficult

Buy, I also have not succeeded.