The situation of light leakage is very good to solve, directly call the official customer service after-sales service to let the after-sales service personnel directly fill the glue can be.
But if it's a problem with the motherboard, then the motherboard should be repaired or replaced.
1, the monitor machine without power
(1) power supply failure: This is a should be said to be very simple failure, the general LCD monitor power supply and power supply two kinds of machine, outside the common some. Regardless of the kind of power supply, its structure is much simpler than the crt monitor power supply, fragile is generally a number of small components, such as fuse, rectifier bridge. Power supply board commonly used ic: 6841203d06, these commonly used pmw chip in my professional LCD parts store can buy. (2) drive board failure: drive board burn insurance or voltage regulator chip failure, some of the machine is the switching power supply built-in, the output of two power supply, one of which is 5V, for signal processing, the other is 12V to provide high-voltage board point backlighting, if the switching power supply part of the circuit failure may lead to the two power supply are not output.
First check the 12V voltage is normal or not, followed by checking the 5V voltage is normal or not, because the A/D driver board MCU chip operating voltage is 5V, so find the fault of the machine, first use a multimeter to measure the 5V voltage, if there is no 5V voltage or 5V voltage has become very low, then one may be the power supply circuit input stage problems, that is, 12V to 5V conversion, the power supply part of a problem. The power supply part of the problem, this failure is very common, check the 5-terminal voltage regulator block (common model 8050SD-LM2596-AIC15-01, etc.).
Another possibility is that the 5V load is aggravated, the 5V voltage is very low, another way of saying is that the signal processing circuitry at the back stage of the problem, part of the circuit is damaged, causing load aggravation, the 5V voltage is very low, one by one to check the back stage of the problem components, to replace the faulty components, the 5V can be restored to normal, the problem is generally solved, but also often encountered! 5V voltage back to normal, but also can not be normal power on, this situation also has a variety of reasons, on the one hand, the MCU program is flushed out may lead to not power on, there is also the MCU itself is damaged, such as the MCU I/O port damage, so that the MCU can not scan the keys, encountered this kind of failure caused by the MCU to look for the hardware problem is useless, even if you change the MCU can not solve the problem, because MCU is the need to program and replace the components that fail. Because the MCU is required to program and write the code, in the absence of a way to find the original AD driver board replacement, we can only use the general A/D driver board replacement, such as: 151D or 161B, etc. 2, the display is lit for a while on the light, but the power indicator green light is always on This problem is generally caused by high-voltage anomalies, is the action of the protection circuitry, in this case, the general LCD screen is a display, see the method is "oblique". The way to see is to "squint".
3, the display black screen, no backlight, the power lamp green light is always on squinting at the LCD screen has a display image, more belong to the high-voltage board power supply circuit problems. Focus on checking the 12V power supply (fuse F) and 3V or 5V switching voltage is normal. If the MCU problem caused by the lack of output switching control voltage, you can directly extract the 3-terminal voltage regulator block (AIC1084) 3.3V instead.
Repair of high-voltage board ideas (power fuse - switching control tube - power management IC - push-pull tube - power switching tube - DA conversion circuit (storage inductor, rectifier) - LC boost circuit (step-up transformer, step-up capacitor) - coupling capacitor - lamp.
4, the screen bright line, bright band or dark line This problem, generally LCD screen failure. Bright line failure is generally connected to the LCD screen body wiring problems or a row and column of the driver IC damage. Dark line is generally the body of the screen has a leakage, or TAB flexible board connection open circuit. The above two problems is basically a death sentence to the machine, there is no repair value, because the price of a screen is too high.
5, off-color failure can generally enter the factory adjustment mode to adjust. If there is no such mode, maintenance ideas: replace the screen line and adapter board - rewrite the driver - driver board is bad (uncommon) - screen backplane control IC is bad (uncommon) - unplug the screen line to observe the backlight color (backlight flat for the aging of the lamp) - change the lamp.
6, character virtual or trailing Check the VGA signal line, focus on whether the RGB three-color line ground connection is normal - replace the screen cable or adapter board - rewrite the driver - change the driver board - LCD screen backplane signal interface IC is bad - LCD screen backplane contrast potentiometer adjustments - LCD screen guide plate misalignment - polarizer misalignment.
7, LCD screen internal stains wipe or replace the protective film - disassemble the screen body to clean the outer polarizer and plexiglass (with cotton balls, pure water treatment) - air blower blow dry.
8, LCD screen bright spot one or two large bright spots, you can try to gently press the bright spot with your fingertips, can disappear, indicating that more than one of this pixel switching tube and electrode false connection. Small black dots and gray dots may be internal light guide plate or polarizer dust, can be cleaned and processed.
9, LCD screen brightness is low check the high-voltage board ADJ brightness adjustment circuit - change the lamp - change the high-voltage board - adjust or replace the light guide plate.
10, error message "out of frequency range" Check the signal line - rewrite the MCU driver - replace the EPROM - rewrite the EPROM program - change the driver board.
11, not press the switch button after power on the white screen appears backlight, after pressing the key image can be displayed normally High pressure board interface switch signal and ADJ signal reverse caused by some of the MCU belonging to the driver board switch signal output is not normal, you can rewrite the MCU program to repair the change of the MCU.
Two, Switching Power Supply Failure:
1. Fuse fuse For fuse fuse failure, usually check the main power rectifier filter circuit in the filter capacitors, rectifier bridge diodes and other components. Of course, the anti-interference circuit failure, can also cause the fuse fuse and black. It must be noted that by the switching tube breakdown caused by the fuse blown is usually accompanied by overcurrent detection resistors and power control integrated circuit damage at the same time. Negative temperature coefficient thermistor is also easier to burn with the fuse, maintenance should also pay attention to their inspection.
2. No voltage output, but the fuse is not blown There is no voltage output, but the fuse is not blown failure, indicating that the switching power supply circuit does not work, or work after the protection state. Repair, first measure the power control integrated circuit start pin whether the start voltage.
(1) If there is no startup voltage or the startup voltage is too low, then check whether the startup resistor and the external components of the pin have leakage.
(2) If there is a startup voltage, then measure whether the output of the power supply control IC has a high or low jump level signal at the moment of power-on. -If there is no jump, the power control IC itself or its peripheral oscillation circuit components or protection circuit failure, you can first replace the power control guillotine IC, after checking the peripheral components of the method to find the fault. If there is a jump, generally more for the switching tube itself is bad or damaged, should focus on its inspection.
3. The output voltage is too low The cause of the switching power supply output voltage is too low failure, in addition to the voltage regulator control circuit is abnormal, there are usually the following three reasons:
(1) switching tube performance degradation. This situation will cause the switching tube can not be normal conduction, so that the power supply's internal resistance value becomes larger, the ability to carry the load becomes worse.
(2) Failure of the rectifier diode and filter capacitor at the output. This situation can be determined by substitution to determine whether they are damaged.
(3) The load of the switching power supply has a short-circuit failure. Especially DC/DC converter short circuit or poor performance. In this regard, you can use the method of disconnecting all the load of the switching power supply circuit to distinguish between the switching power supply circuit is bad or the fault of the load circuit. When disconnecting the load circuit, the output voltage returns to normal, then it means that the load is too heavy; if it still can not return to normal, the switching power supply circuit is faulty.
4. The output voltage is too high The output voltage is too high phenomenon, most of the failures in the switching power supply voltage regulator sampling and voltage regulator control circuit. Should be by the sampling resistor, error sampling amplifier, photocoupler, power control integrated circuits, such as the composition of the feedback loop components to check. The incidence of deterioration of the sampling resistor, damage to the precision regulator amplifier or opto-coupler is usually high. For switching power supply with over-voltage protection circuit of the phenomenon of excessive voltage, you can first disconnect the over-voltage protection circuit, and then quickly measure the voltage on the main output of the power supply at the moment of power-on.
If the measured voltage is still higher than normal (generally as long as it is higher than 1V or more, are overvoltage fault), it should be overhauled according to the above overvoltage fault.