Tips for repairing t-con board

 The typical failure of the logic board is: no image, intermittent color lines in the vertical direction of the screen, and no characters (this is very important). Can test the screen voltage, 5V or 12V depending on the screen model. Then test the voltage on the LVDS output interface to see whether there are changes in the static and dynamic conditions. If it does not change, it can basically be judged that there is a fault on the logic board. 1.2V or so), if possible, it is most reliable to replace it with a same logic board. As long as the format is the same as the upper screen voltage, it can be replaced, so that we can find and confirm the fault point. The LVDS lines from the main board to the logic board have a certain pattern. The red line on the side is the positive pole of the power supply, and the black line is generally the negative pole of the power supply. The LVDS signal lines are twisted together (4 pairs—single 6 bits; 5 pairs— Single 8-bit; 8 pairs-double 6-bit; 10 pairs-double 8-bit), now some logic boards and screens are connected together, called X+C integrated type, generally the screen below 32 inches, 32 Screens larger than inches are generally composed of X+C separation type (small screens are mainly considered by cost). Due to technical and precise characteristics, they are generally not easy to repair. If the principles are thoroughly understood and the welding technology is excellent, repairing the logic board is not a myth! Damage to the logic board will cause the screen to not display images normally, and of course there is no menu display, but the buttons and remote control work (remember this). There are many small color dots in the middle of the screen with poor connection between the logic board and the screen. You can plug and unplug the cable to confirm; both the logic board and the screen can cause the image to get screened, but the screen on the logic board is different from the screen. , The blurry screen of the logic board is shown as a regular blurry screen from top to bottom. We can change the signal source or change the 4:3 mode to confirm.

Logic board maintenance summary (maintenance ideas)

1. Visual inspection to see if there is obvious blackout or abnormal color of vulnerable components such as main chip power supply IC, filter capacitor, etc.;

2. Test the resistance to test whether the short circuit resistance of each power supply test point becomes smaller, and whether the insurance is open or not;

3. Voltage measurement to test whether the power of each power supply measurement point is normal (①Power supply Vcc5V/12V, ②Main chip 3.3V; 2.5V; 1.8V, 1.2V, etc., ③VAA14V, VGH20V, VGL-5.5V, ④VREF13V, VCOM 6V) ；

4. Measure the resistance of the IC signal line to ground, whether the data exchange between the LVDS DDR and the main chip is defective;

5. Check whether there is poor contact between the power strips of each connection line and the logic board, and the power strips between the logic board and the screen.