Repair of switching power supplies. Capacitor instead of lamp. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Chargers, batteries, galvanic cells
Comments on the article
When repairing switching power supplies, both television, monitor, and computer, it is recommended to turn on a 220 V incandescent lamp in the break of the network wire [1, 2]. However, there is another safe method that has been proven over the years (but maybe not so well known) when a non-polar capacitor is connected to the break in the network wire.
It is convenient to solder the capacitor to the legs of the fuse holder on the board, removing the latter. It must be remembered that the power supply unit (PSU), as in the case of a lamp, must be disconnected from the main load, otherwise it simply will not turn on. Where the PSU is not made as a separate unit, in monitors and imported TVs, you should turn off the most loaded circuits - the power supply for horizontal and vertical scanning.
When connecting to the network, you should first make sure that there is a voltage of 300 V (or slightly lower) on the capacitor of the diode bridge. If it is absent (all voltage will drop on the capacitor, I repeat - this is the essence of protection) or less than 200 V, the power supply is faulty.
As in the case of the lamp power, it is possible to control the load current to some extent by varying the value of the capacitance of the connected capacitor - in practice, within 2 ... package" of 8 ... 3 capacitors of 5 μF type K1-73). The operating voltage of the capacitor must be at least 17 V.
Attention! A dangerous charge can be stored on the capacitor. To reduce the likelihood of electric shock, it can be recommended to connect a discharge resistor with a resistance of 100 ... 300 kOhm in parallel with the capacitor.
The lamp can still come in handy when looking for all sorts of short circuits in horizontal scanning. To do this, include it in the break of the secondary power circuit (B +) or in the monitor instead of the "chopper" (secondary power supply made on a MOSFET transistor). Now it is possible to examine with an oscilloscope the reverse pulses (ROI) on the collector of the transistor, which was previously impossible without a specific, and, moreover, expensive high-voltage divider.
Literature:
- Silaev A. On the repair of power modules. - Radio amateur, 1996, No. 9, p. 5.
- Color TVs "Horizon" 2USCT-51-61. Repair manual. - Minsk, "Polymya", 1987 (for specialists of repair enterprises).
Author: Anatoly Kutovoy Visaginas, Lithuania; Publication: radioradar.net
See other articles Section Chargers, batteries, galvanic cells.
Read and write useful comments on this article.
<< Back
Latest news of science and technology, new electronics:
Machine for thinning flowers in gardens
02.05.2024
In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers.
... >>
Advanced Infrared Microscope
02.05.2024
Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>
Air trap for insects
01.05.2024
Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>
| Random news from the Archive eVTOL electric flying car
06.01.2023
Aska unveiled the eVTOL electric flying car with a range of 400 km.
The Aska A5 is about the size of a typical SUV and has been described as the first four-seat electric vehicle that can travel on the road and up to 250 miles (402 km) in the air on a single charge. Although the A5 looks more like an airplane/helicopter than a traditional car, it has wings and propellers that can be folded down when it needs to be used as a car.
The vehicle is powered by a proprietary system combining lithium-ion batteries with a gasoline engine acting as an onboard range extender. It's unclear how much power the A5 has, but Aska notes that it has four electric motors in the wheels that provide all-wheel drive traction while also improving aerodynamics and maximizing interior space.
Although the A5 can take off like a helicopter, or use a runway like a traditional plane. During flight, the wings and six rotors deploy. Asuka notes that the wing has been optimized for "glide, smooth landings and energy efficiency."
"Our unveiling at CES represents something that has never been achieved in the world, but what people have been dreaming of for decades: a fully functional, full-scale prototype of the Drive&Fly electric VTOL, a true flying car," described co-founder and CEO Guy Kaplinsky.
"We are making history out of ASKA and defining the next 100 years of transportation. ASKA is positioned as a next-generation vehicle that combines the convenience of a car with the ease and efficiency of VTOL and STOL flight. ASKA is a vehicle not only for consumers, it also has significant business - potential for use in emergency response, military, and shared mobility services on demand."
In addition to private sales of the A5, Aska plans to launch a ride-to-order service in 2026 with a fleet of its eVTOLs.
|
Other interesting news:
▪ MEMS microphones from Akustica: a new word in sound processing
▪ 6Gbps Wireless Platform
▪ Optimists are not afraid of a heart attack
▪ The main cause of cancer has been identified
▪ A new way to repel ice
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ section of the site House, household plots, hobbies. Article selection
▪ article by Aphra Ben. Famous aphorisms
▪ article When is Pi Day celebrated? Detailed answer
▪ article The razor drills. home workshop
▪ article Remote probe - frequency divider by 10 for frequency counter FC250. Encyclopedia of radio electronics and electrical engineering
▪ article Magic gum. Focus Secret
Leave your comment on this article:
All languages of this page
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese