Automation is the trend of industrial development now, and the application of liquid crystal displays can be seen everywhere, such as automatic printing machines, reflow soldering with computers, etc. However, the more applications, the more problems. Although the internal and external environments are different, the reasons for the problems may be similar.
The following collected articles are for reference, and I hope to help netizens with similar problems.
Breakdown phenomenon: At the beginning of the year, my friend replaced a 15-inch LCD monitor, the model is AOCLM-500, and it has been used normally. But just half a year later, this LCD display has malfunctioned. The specific performance is as follows: as long as the computer is started or restarted, a failure phenomenon similar to "flower screen" will appear, giving people the feeling of high-frequency electromagnetic interference. The writing on the screen is very blurry and jagged. After entering the Win98SE system, this kind of failure phenomenon will occasionally occur, but the duration is very short and not obvious, most of the time the screen display is normal.
Fault check: I first replaced a graphics card and found that the fault is still there. Then, a working 17-inch CRT flat-screen monitor was used as a replacement and exclusion test, and no similar failure occurred.
Analysis of LCD monitor failure principle: Digital interface (DVI) was originally the best interface for LCD display, but graphics card manufacturers generally do not have a digital interface on the graphics card due to cost considerations, and through the internal digital / analog conversion circuit and the VGA interface of the graphics card Connected. Although this type of connection solves the problem of signal matching, it also brings the problem of distortion due to interference. The reason is mainly because the clock frequency of the LCD display is difficult to maintain 100% synchronization with the clock frequency of the input analog signal, especially when the frequency of the analog synchronization signal is constantly changing. If the LCD synchronization circuit at this time, or If the transmission line connected to the synchronization signal of the graphics card has short circuit or poor contact, and the follow-up cannot be adjusted in time to maintain the necessary synchronization relationship, the startup display exception encountered in this article will appear, and it will display normal after entering the system. Strange phenomenon.
Based on this, the author judges that the fault point is probably the synchronization circuit inside the LCD, or the connection interface pin and the transmission cable.
Fault resolution: Considering that the internal synchronization control circuit of the liquid crystal display is generally set inside an integrated circuit, and the possibility of damage to the integrated circuit is minimal. So the author put the focus of the inspection on the adjustable pins of the interface pins, transmission cables and synchronization circuits.
First, disassemble the LCD display case to expose the internal connecting cables, check the buzzer block with the digital multimeter on and off, and check the continuity between the connecting pin and the corresponding cable one by one, and no physical connection such as open circuit or short circuit is found. Sexual issues. Then follow the direction of the cable connection line, find the input control circuit unit on the printed circuit board, and find that two miniature semi-adjustable potentiometers are installed on the side of the 14-pin packaged integrated circuit block, one is marked as on the printed circuit board. WR604, the other is WR1201. Based on my previous experience in repairing CRT monitors, I preliminarily judged that these two miniature semi-adjustable potentiometers are probably used for synchronous fine-tuning, but which one has a problem? In order to stabilize and reduce the number of times to disassemble the LCD display case, the author cleaned and wiped the two semi-adjustable potentiometers with anhydrous alcohol. After all the alcohol volatilized, the LCD display case was restored and energized to test the machine. It has been alleviated, but sometimes the fault will be repeated during several consecutive startups. Frustrated to disassemble the LCD display case again, use a micro-cross screwdriver to adjust the WR604 clockwise a little, and then restore the case and power on again to test, the LCD display shows normal, so the fault has been eliminated. Although a few adjustments can make the LCD display temporarily return to normal work, but with the use of longer time, the author believes that the failure is likely to repeat. Therefore, the author considers that the fundamental solution is to replace a semi-adjustable potentiometer. It is a pity that this kind of semi-adjustable potentiometer, which is not much larger than mung bean grains, is difficult to buy in the ordinary electronic market, and the author has never been as expected.
We provide round, square, rectangle, irregular shape Flower Boxes, goods in stock, also provide custom logo flower boxes.
Kinds of flower wrapping papers.
Flower Boxes,Wrapping Paper,Custom Flower Boxes,Florist Bouquet Boxes,Bouquet Wrapping Paper
Zenghui Paper Package Industry and Trading Company , http://www.zhpaperpackage.com