1. 1 basic structure of lcd television
The internal structure of lcd tv is shown in figure 1-1. Figure 1-1 (a) is the internal structure of regular large-screen lcd television, figure 1-1 (b) is the internal structure of regular small-screen lcd television, and figure 1-1 (c) is the internal structure of the led super thin lcd television。
As can be seen from the graph, power panels are connected to other components through plugs and line lines and can be replaced with computers。
As shown in figure 1-1 (a), the internal structure of regular large-screen lcd television consists of power panels, master plates, high-pressure plates (all known as background light-source high-voltage drives), logical plates, liquid crystal screen components (background light tubes), horns, etc. The power panels are responsible only for the supply of electricity to the main plate, the high voltage plate, the logical panel and the screen component circuits are supplied from the main plate (open/stand-by circuit, provided by the main plate input +12v or +5v control voltage); the work of the high pressure lamp tubes in the screen is from the high voltage plate。
The internal structure of regular small screen lcd television, including power + high pressure plate, main panel, logical panel, liquid crystal screen component, as shown in figure 1-1 (b)。
The internal structure of the led superline crystal television, including power + led light drive, main plate, logical board, liquid crystal screen components, etc., as shown in figure 1-1 (c). Power + pressure plate is provided directly to the main plate, to the high pressure lamp tube within the screen. The supply of electricity from the main panel for the logical panels and screen components is as shown in figure 1-1 (a)。
Figure 1-1 internal structure of lcd television
(1) lcd tv components with high failure rate board
The lcd television was problematic, 70 per cent of which was caused by electric panels and background light-source high voltage panels. The 30-inch (1 inch = 2. 54 cm) and the following small screens, the regular lcd television, mostly combines power circuits and background light-based high voltage circuits on one circuit board. New types of led-backlight ultra-lique-crystal televisions, because of their relatively small power, typically use the power panel circuit and led-back-light drive as a circuit board。
In summary, the power panels are the highest failure points for lcd television. The power panels are also the components of the lcd television that are most easily maintained and are maintained in a manner similar to that of the crt colour switch。
(2) characteristics of power panels
The power plate is a voltage converter responsible for converting 220vac to the voltage required for other components in the lcd television. Once the 220v power is connected, it enters the operational status of the stand-by, starts the output of the +5vs standby power, provides the cpu control system on the main panel, starts the operation of the cpu control system, provides the power source plate for the output of the high-altitude opener control signal when it is received from the panel or from the command input of the remote control, activates the power plate into the full working state, output of the +12v etc., provides the main panel, background light source high voltage panel, initiates the work of the lcd television, and displays colour images and acoustics after processing the received television signal。
Source plates for lcd tv are shown in figures 1-2. It is responsible for the power supply and output of the whole machine, which is the highest failure point for lcd, and for the electrical component (i. E., voltage flow and conversion between 220 vac and load power), which works in a “three-high” (high voltage, high current, high temperature) state, which is large and is a high failure zone. Of which:
Figure 1-2 lcd panels
1 high voltage can easily result in bulk electrolytic convulsions, large power transistor tubes (including bridge integers, power blocks, switch tubes, voltage output piping) fixed on the radiator plate。
2 high currents can easily cause the break-up of insurance tubes and larger insurance electrical blocks。
Three high temperatures, easily induced devices, welding, burning, electric decomposition nearby。
Experience
Three heights of equipment were damaged, some accompanied by external manifestations such as drum packs, burns, cracks, etc。
It is easy to deal with the above-mentioned issues for those who maintain the crt colours or have some knowledge of electricians, so repairing the lcd panels is not difficult, even simpler than repairing the crt colours。
