Yesterday, I worked on a Changhong 2539A TV and found that the image was extremely dark when it started up. I tried adjusting both brightness and contrast to their maximum settings, but there was no improvement. I checked several key voltages: the cover light measured 4.2V, the acceleration voltage was 340V, and the RGB lines were at around 175V, which all seemed normal. Next, I checked the reverse input pin 34 of the large IC TDA9373, which should have a pulse signal. However, it read only 0.5V, indicating no signal. But even without a pulse signal, it wouldn't usually cause the screen to be completely dark or black. I then moved on to check the black current detection terminal, pin 50, which had a voltage of 5.5V—this was normal. The issue likely lay in the ABL (Automatic Brightness Limitation) circuit. I looked at pin 49, which is the ABL input. Its voltage was only 1.6V, which was lower than expected. When I temporarily pulled up this pin, the voltage rose to 3.8V, and the picture brightness improved significantly. This confirmed that the problem was in the ABL circuit. Further inspection revealed that diode VD485 had abnormal resistance values and showed signs of leakage. When I tested resistor R485 during the test, it measured over 700kΩ, which was much higher than the typical 100kΩ. Upon removing it for measurement, it turned out to be open. I replaced the diode and installed a new 100kΩ resistor. After reassembly, the voltage at pin 49 increased to 3.6V, and the TV worked properly again. The repair was successful.
AD8 standard floating Solar Cable is a kind of equipment used for floating photovoltaic power generation. It consists of photovoltaic cells that convert solar energy into electricity. The device is designed to float on the water, while it can be fixed to the water by a buoy and anchorage device to prevent drifting.
AD8 standard floating solar cable has the following characteristics:
1. Efficient use of solar energy: photovoltaic cells can convert solar energy into electricity to achieve efficient power generation.
2. Environmentally friendly: photovoltaic power generation does not produce pollutants and greenhouse gases and is environmentally friendly.
3. Save land resources: Floating solar cable can use the space on the water surface, saving the use of land resources.
4. Strong wind and wave resistance: floating solar cable adopts stable design, has strong wind and wave resistance, and can operate normally in bad weather conditions.
5. Easy installation and maintenance: Floating optical cables are relatively simple to install and maintain, and can be quickly deployed and adjusted.
AD8 standard floating solar cable is suitable for a variety of water environment, such as lakes, reservoirs, rivers, etc. It can be used in power stations, farmland irrigation, drinking water treatment and other fields to provide local clean energy and power supply.
AD8 Floating Solar Cable,Solar Adapter Cable,Waterproof Solar Cable,DC Cable
Suzhou Yonghao Cable Co.,Ltd. , https://www.yonghaocable.com