A friend of mine owns a Changhong PF2139 color TV that frequently blows the 3.15A fuse when turning on. Once it starts, it works fine and can be watched normally. This issue has persisted for almost a year. Several technicians tried to fix it, but the problem still occurs occasionally. One day, he came to me with his frustration. He didn’t have the tools at the time, so he brought the TV back later.
I decided to take a closer look at the power supply, which is commonly known as A3. I thought the problem might not be too serious, but why haven't many people fixed it? After checking, I noticed the fuse was blown, but not in a typical blackened way. There was some white smoke on the glass tube, suggesting a less severe overcurrent situation. I wasn’t sure if it was a faulty fuse or a problem with the power supply components. I then took out the circuit board and found that the power supply had been heavily modified, indicating previous attempts by others.
There were no obvious shorted components, so I tested it again with a 3.15A fuse, and it blew again. I disconnected the C pole and removed the degaussing coil before trying the fuse again. Then I removed the three-terminal degaussing resistor and checked the four diodes—no short circuits were found. I replaced the fuse with a regular 2A one, and it burned again. At this point, my suspicion fell on the 400V filter capacitor.
I removed the capacitor and tested its charge and discharge. It was a 470uF/450V capacitor, which should have been replaced by the previous technician. I tried replacing it with a 100uF/400V filter capacitor instead. When I powered it on, the voltage across the capacitor was 300V, which was normal. I reassembled the circuit and turned it on. The screen displayed a blue image without any issues.
To further verify, I used the removed 470uF/450V electrolytic capacitor in a 29-inch color TV power supply. It worked perfectly, with no problems even after multiple startups. This confirmed that the original 21-inch TV had a large-capacity filter capacitor.
The reason behind this issue is likely due to the larger capacitance causing a higher inrush current during a cold start. This excessive current can blow the fuse. If the fuse were upgraded, it could cause more damage to the rectifier bridge. Therefore, the power supply’s filter capacitor shouldn’t be oversized—it needs to be just right for the system.
The EI 41 Transformer is a specific transformer model,
Key Features
EI-type Core: Known for their good heat dissipation and reduced electromagnetic interference (EMI).
Potential Power Range: Although specific power ratings vary, EI transformers are commonly used in medium-power applications. The EI 41 model might be suitable for power ranges from several tens to hundreds of watts, depending on the design and intended application.
Efficiency and Losses: Modern EI transformers aim for high efficiency and low losses, employing advanced materials and design techniques to minimize energy waste.
Customization: Depending on the manufacturer, the EI 41 Transformer may offer customization options such as different voltage ratios, insulation classes, and mounting configurations.
Applications
Electronics: As a power conversion or isolation component in a wide range of electronic devices.
Audio: In audio amplifiers, loudspeakers, and other audio equipment, where stable power and signal isolation are crucial for optimal sound quality.
Industrial Automation: In control systems and power distribution networks within industrial environments.
Lighting: In LED, fluorescent, and other types of lighting systems, converting line voltage to suitable levels for the lamps.
Ei 41 Transformer,Ei41 Line Transformer,B11416 Transformer,Ei Type Transformer,transformer manufacturers
Guang Er Zhong(Zhaoqing)Electronics Co., Ltd , https://www.geztransformer.com