Take a TCL--L32W3212 LCD TV and turn it on with a black screen. Measure the constant current drive board 24V power supply normal, the output terminal rises to more than 40 volts and drops to 24V at the instant of power on, and the 1K resistor is connected to both ends of C808 to cancel the protection boot, the screen is bright and black screen, and the output filter is replaced by 250V22UF capacitor. The chip capacitor failure does not change. (The above two methods are from the forum query.) The forum queryed the machine lamp beads is easy to break, decided to open the screen to change the lamp beads. Insulated Copper Tube Terminals Insulated Copper Tube Terminals,High quality insulated terminal,copper tube terminal Taixing Longyi Terminals Co.,Ltd. , https://www.longyicopperlugs.com
Disassemble the rear cover fixing screws, the TV screen is facing up, the rear cover is placed flat on the table, and the front case is removed. Remember not to put the screen down, which will easily damage the screen. Carefully remove the LCD screen and put it in a safe place. Then remove the light board to expose the LED light bar. This machine has 7 light bars. Careful measurement found that the above 6 individual light beads are not bright but not broken down, the bottom one has several light beads in a breakdown state, decided to replace the lamp beads.
Because the first replacement of this kind of lamp bead, it took a lot of twists and turns, write to the peers for reference: first use two soldering iron to remove the lamp beads, it is not easy to remove, the plastic cover on the lamp bead is removed, the lamp The beads are thrown there and welded there. When they are loaded, they are not easy to get. They are blown with a wind gun. It is very easy to disassemble. When loading, take the light bar in one hand and the air gun in one hand. The lamp beads cannot be put up. Then use the old-fashioned electric iron, heat it and put it on the table. Hold the light bar in one hand and hold the lamp with a pair of dice. Gently raise it up, the lamp bead is taken down, and all the bad lamp beads are taken. Next, there is no same lamp bead. Find the light bar that was cut off before the display and remove the lamp bead. The length of this lamp is the same as that on the TV. It is a bit wider, so it can be used.
After all the replacement, the installed machine experiment. Then measure the voltage of the LED power supply terminal has reached about 65V. The test machine image also returned to normal. In addition, because the white strip is attached to the light strip, it was originally intended to be removed when the lamp was taken, but it was revealed when it was exposed. Later, several pieces were simply uncovered, and the parts placed on the iron were burnt and deformed. When it comes to time, it shouldn't have much impact, so I don't care about it. Attach a picture for reference: