About a month ago, a customer called to say that the TV suddenly flashed brightly and the sound was always normal. Check that the Power Supply board model is JCL35D-2MC, the PFC has 390v, the power output has two sets of motherboard 12V and light bar 70V. The test group 2 sets the voltage is completely normal, and the LED power supply needs to be boosted to 124v or more [3 groups * 12 pcs / Group *3.3V=118.8V], but the power board rises to 124v and immediately falls and resumes the cycle. The problem of the external light bar is unchanged, the backlight management of the power board is out of order, the management chip PF7001 is replaced, the resistor. Capacitance. Disassemble the machine. Go to the glue, no problem is found, it is necessary to replace the new power board backlight. The bad board brings back the data review after repeated investigations. Starting from the detection and protection, the 6 feet of the PF7001 are: overvoltage protection setting feet, set to 2.5V in this scheme, RL32 is external 10K to ground resistance, technical transformation After 8.2K, the LED output voltage will be stable at 124V-152V, no backlight protection flashing, in fact, the voltage drop on the light bar is only 120-130V. Guangzhou Lufeng Electronic Technology Co. , Ltd. , https://www.lufengelectronics.com
After the compensation, I can only honestly explain to the user slowly. The cracks on the screen are not known when the screen is not bright, or the two of us have just changed the light bar. The sheets on the coffee table are flat and neat. I also agreed that we are very careful, there is no place where it is wrong. Since the incident has already happened, this TV has a new price of 2,300 yuan. I can only compensate you for 1,000 yuan. I put in the light bar 200 material. For a long time, everyone only saw the thief eating meat, and did not see the thief beaten. This is the risk, it is not easy to earn some money.
Changhong LCD TV LED55C2000I repair lost money experience - appliance repair - Database & Sql Blog Articles
The light bar is bad, but just a few days ago, I called the TV set and it didn't work. This time the screen didn't light up or there was a sound. I explained that if it was a problem, we were responsible for the free replacement, and this time we measured the PFC. 390V, 12V, 70V normal, LED voltage to 150v fall protection, it seems that you have to open the screen to change the Lamp beads, anyway, often more familiar. The trepidation work was carried out on the user's oversized coffee table and dining table, all with thin sheets and flowers. Because the TV is too big, I cooperate with the user. Carefully put the screen [without the front frame] on the coffee table. The machine can be separated by a plastic buckle, and it is not necessary to remove the screen from the front. Bigger]. Screen splitting to check the lamp bead short circuit. The open circuit is broken and a total of 28 pieces are recorded. Only the light bar can be replaced. The store has improved type [the original machine has 3 * 12 lights and two groups, and the improved type 3 * 14 lights two groups and 】 When we changed the light bar very well, the screen was reset, and when the power was tested, we found a thin crack on the screen. At that time, the user did not find it. I pointed out that there is [you can look carefully. 】.