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Segment code LCD damage phenomenon and repair judgment method

09.25.2023

1. Liquid Leakage from the LCD Screen

Analysis and maintenance: LCD leakage is mostly caused by external squeezing, collision, falling from height, etc. on the surface of the screen, most of them are in the middle of the screen, you can see the obvious glass cracks, with hand pressure leakage part, you can see the trajectory of the liquid crystal force movement is along the direction of the crack. In addition, the seal is damaged, mainly in the four edges of the screen location, such as drinks, juice, tea and other acidic and alkaline liquids in the process of use, if accidentally from the outside into the edge of the screen infiltration, the sealant will be damaged, the liquid crystal inside will leak, a few screens used in the production of sealant will also have some problems, this will also happen. Repair method: need to replace the OPEN, CELL LCD panel, belongs to the professional repair, the general repair is to replace the screen.

2. The Screen has a Vertical Dark Line, Dark Band or Horizontal Dark Line, Dark Band

Analysis and maintenance: this is most likely the screen COF [grain soft film structure] line is damaged or COF, Bongding liquid crystal friction caused by poor jointing. Maintenance method: need to replace the COF line or re-Bongding liquid crystal sassafras welding. General maintenance and multi-screen replacement processing.

3. The Screen has a Vertical Bright Line, Horizontal Bright Line

Analysis and maintenance: this phenomenon is the screen TFT internal circuit problems, maintenance methods: OPEN, CELL needs to be replaced. General maintenance requires replacement of the screen processing.

4. The Backlight does not Light, but can be opened

Analysis and maintenance: this is mostly caused by the backlight torso or backlight bar problems. At this point, use a flashlight to shine light from the side, you can see the image. Maintenance method: need to replace or repair the backlight board or light bar.

5. White Screen

Analysis and maintenance: this screen does not have a central control board, most of the PC board U3 and U4 defects caused by the maintenance, as long as the six pins of U3, U4 are less than 300 ohms and less than 200 ohms, respectively, you can determine the U3 or U4 defective, replace the fault can be removed.

6. Irregular Splash Screen

Analysis and maintenance: no screen after the power on, after the warm-up screen, but touch the center board with your hand, the image is back to normal, the image clearly appears when the hand shaking the center board screen. Disassemble the center board to check the screen and the center board of the line is a little loose, trimmed to remove the fault.

7. Image Abnormalities

Analysis and maintenance: just turn on the monochrome screen defective area image from large to small, back to normal. After investigation, the fault is the glass substrate fracture. In this type of screen there are many similar adverse phenomena, some of which are accompanied by a horizontal line at the top, most of which are caused by damage to the glass substrate. Usually need to replace the screen to deal with.