Yesterday, a female customer brought in a Changhong H21K59 TV for repair. The issue was that the power-on indicator was on, but there was no picture or sound. I turned it off, removed the back cover, and took out the main board for inspection. Upon close examination, I noticed several desoldered points around the power output section and the high-voltage package. I carefully re-soldered each of them, even re-welding the TB1238 chip. After powering it back on, I measured a voltage of over 70V on the +B line. When I pressed the "program +" button, the voltage increased to 120V. The AC voltage on the wire was measured at 5.5V, and the three cathode voltages of RGB were all around 190V. The acceleration voltage was also present. However, the screen remained completely black. When I increased the acceleration voltage, I could see the retrace line on the screen. Further testing showed that the voltages on pins 18, 19, and 20 of the TB1238 were all 0V. Based on this, I concluded that the TB1238 chip was faulty.
I explained the situation to the customer, who agreed to proceed with the repair. I informed her that I would get the TV back to her the same day. Today, I went to the wholesale market and purchased a used TB1238AN chip. After installing it and testing the TV, everything worked properly. The screen lit up normally, and the audio function was restored. It was a bit of a tricky repair, but the customer was happy with the result. I took a photo of the new chip and the working TV for documentation.
Vision SE is our specialist vision solution offering a wide range of classification services. Through advanced image processing, we realize professional-level visual technology, which is suitable for medical image processing, scientific research and other fields. We focus on performance optimization to make it an industrial-grade solution that is widely used in factory automation and high-demand application scenarios. At the same time, we pay attention to data security and privacy protection, ensuring that the highest standards are met when processing images and data. Vision SE's classified services exceed expectations, providing high-performance and professional-grade vision solutions to various industries.
vision services,vision sensor,vision sense,vision se,vision se review
Ningbo Autrends International Trade Co., Ltd. , http://www.visionsemr.com