Character LCD Display Simple Failure

- May 26, 2017 -

Character LCD Display This is a very simple fault that should be said, the general liquid crystal display in the extension of power and external power supply two, the machine outside the common some. Regardless of that kind of power supply, its structure is much simpler than CRT display power supply, easy to damage is usually some small components, like insurance tube, Rectifier bridge. Character LCD Display 300V filter capacitor, power switch tube, power management IC, rectifier output diode, filter capacitor and so on. Power board commonly used Ic 6841 203d, Character LCD Display these commonly used PMW chips in my professional LCD accessories store can be bought.

Drive plate burning insurance or voltage regulator chip failure, some of the machine is the switching power supply built-in, the output of two sets of power supply, Character LCD Display one group is 5V, for signal processing, the other is 12V to provide high voltage plate point backlight, if the switching power supply part of the circuit failure will likely lead to two sets of power supply is not output. Check the 12V voltage Normal No, followed by 5V voltage Normal No, because A/D drive plate MCU chip operating voltage is 5V, Character LCD Display so look for failure to open the machine, First use a multimeter to measure 5V voltage, if there is no 5V voltage or 5V voltage becomes very low, then one may be the power supply circuit input level problems, that is, 12V conversion to 5V power part of the problem, this kind of fault is very common, check 5-end regulator block (common model 8050s, etc.).

Another possibility is that the load of 5V is aggravated, the 5V voltage is pulled very low, another way of saying is that the signal processing circuit of the latter stage is out of order, some of the circuit is damaged, and the load is increased to pull the 5V voltage is very low, Character LCD Display one after another to troubleshoot the components of the problem, replace the faulty components, 5V can return to normal, the fault is generally resolved, also often encountered 5V voltage return to normal after the normal boot, this situation also has a variety of reasons, On the one hand, MCU program is washed away may lead to no boot, there is the MCU itself damage, such as MCU I/O mouth damage, so that MCU can not scan the button, encountered this caused by MCU fault, Character LCD Display the problem of finding hardware is no use, even if you change MCU also can not solve the problem, because MCU is required to program and write code, in no way to find the original AD Drive Board replacement, we can only use a common A/d drive plate substitution such as: 151D or 161B.

The squint liquid crystal screen has the display image, belongs to the high voltage plate power supply circuit question. Focus on checking 12V power supply (fuse f) and 3V or 5V switch voltage is normal. If the MCU problem caused no output switch control voltage, can be directly extracted 3-end regulator block (AIC1084) 3.3V instead. The idea of repairing the high pressure board (power fuse------------------power management Ic-------------- (Energy storage inductance, rectifier tube) Jean-Leck boost Circuit (step-up transformer, Character LCD Display step-up capacitor)-------------------tube

The light line fault is usually connected with the LCD body's line out of the problem or a row and column driver IC damage.

The dark line is usually the main body of the screen leakage, or tab flexible plate wiring open. The above two kinds of problem basically is to the machine to sentence the death penalty, does not have the maintenance value,Character LCD Display because the price of a screen is too high. Character LCD Display (Guangzhou has a special replacement of the code, very high fees, rate also high).

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