The most popular recycling method of waste househo

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With the development of the times and the continuous progress of technology, high-quality audio-visual equipment such as large screen color TV sets, advanced CD/MD music centers and DVD players have been widely popularized in recent years. I'm afraid no one is interested in the tape recorders, video recorders and VCDs that we used to have at home. It is understood that many people have not moved tape recorders and video recorders for many years, and it is time for VCD to be upgraded. Some people even treat these obsolete household appliances as second-hand goods or even waste products, which is a pity

it is true that although these obsolete household appliances are indeed out of date, if we can make use of our little radio knowledge or ask friends with radio expertise to help us transform them, we can turn waste into treasure and make the best use of everything. Here are some practices of the author

split dual card radio recorders

the 1980s was the era of the popularity of split dual card radio recorders, and many families still had these "big appliances" of that year. The author once had a large jewelry brand split double card recorder at home. When he first bought it, he felt that the sound quality was really good. He has been using it for many years. Until I bought a set of high-end Music Center, the double card recorder was put aside, feeling "it's a pity to abandon it, but it's tasteless to use it". Then he had an operation and transformed it into a set of small active speakers. The specific methods of transformation are as follows:

first, remove the left and right speakers of the jewelry brand recorder from the fuselage for standby. The original power amplifier of the tape recorder uses a low-power integrated circuit tda2004, with a power of only 5W × 2. The reserve power is too small, so it is decided to abandon it. So I ordered a piece of 20 W power by mail × 2 lm1876 power amplifier board and a 50W power transformer cost less than 100 yuan in total. Then open the back cover of a speaker, replace the small support board inside with a larger board that needs to be leveled before the beam can work, and then fix the lm1876 power amplifier board and 50W power transformer on the board. A certain distance should be opened between the two. A thin iron sheet should be used to shield the power transformer to prevent the power amplifier circuit from being disturbed by the magnetic leakage. Another 10K × 2 volume potentiometer, a mono 3.5mm socket (used to output another channel signal) for the growth of some models in the civil helicopter and business jet market is fixed to the back cover of the speaker. Finally, the power line and audio input line are simply connected, and the whole modification work is completed

this set of small active speakers can be used not only for multimedia computers, but also for surround sound channel speakers in home cinemas. It is very convenient and practical

The popularity of VCD and DVD has turned the video recorder into a superfluous household appliance. In fact, many video recorders have reached a fairly good level in terms of quality and function. Many models have functions such as 99 sets of program preset storage, cable TV supplementary channel reception, "Liyin" demodulation and hi fi stereo recording. These functions still have use value, but people have not made full use of them

at present, cable TV is widely popularized throughout the country. Most cities can already provide 30 or 40 sets of TV programs, and may soon increase to 60 or 70 sets or even more. However, some old TV sets have no additional channel receiving function of cable TV, and can only pre tune and store 20 or 30 channels, which obviously can not meet the current needs. Although these problems can be solved by replacing the cable TV tuner and adding memory, it is troublesome. If you plug the video recorder into the middle of the TV cable and the TV, let the video recorder receive and demodulate the audio and video signals, and then connect it to the TV through the AV terminal, you can solve the problem of multi program reception. The problem of receiving the "Liyin" telepresence programs already broadcast by TV stations in Beijing and Guangzhou can also be solved in this way

in addition, the hi fi video recorder itself is a high-quality analog recorder. Due to the use of rotating magnetic head, frequency modulation, dynamic compression and deep multiplexing technology to record dual channel stereo signals, the sound effect of hi fi video recorder is much better than that of ordinary tape recorder. It has the advantages of wide frequency response (20Hz-20KHz), large dynamic (90dB) and small distortion (0.005%), which can meet the requirements of high fidelity. The author and some friends around still like to use it to copy CD music. Whether you are an enthusiast or an ordinary user, if you make good use of the function of hi fi video recorder, you will no longer have to pay a high price to buy MD or watch cd-r/rw recorders

vcd player

with the growing popularity of DVD, the utilization rate of previously purchased VCD players is getting lower and lower. Many people think that since they have purchased DVDs, VCDs naturally have little use value

however, let us not forget that VCD can play CD records. However, the sound quality of CD playing by VCD is poor (the same is true for DVD). The main reason is that the signal has to pass through the mpeg-l decompression board, and the sound pollution and interference are heavy; 2. in consideration of cost, VCD generally uses low-grade audio DAC decoding circuit. Therefore, only by reforming the VCD, can it play the beautiful sound of CD

in fact, it is not difficult for VCDs to have better sound quality. First of all, they have unique advantages in movement. Many domestic VCDs use high-performance Philips Digital Servo movement. This movement has high precision and error correction ability in reading CD signals, which is far better than Sony analog servo movement used in general CD players. The digital servo circuit can automatically adjust the state of the movement system to maintain all parameters at the set optimal value, so as to ensure the stability of the work. Therefore, the sound quality of a machine using a digital movement should be much better than that of an analog movement. Obviously, the focus of the VCD transformation is to solve the problem of CD signal processing circuit, mainly to add a high-quality audio DAC decoding board

the author has a Jinzheng s-vcd, which uses the Philips Digital Servo movement. Due to the poor sound quality of its CD playing, it spent more than 200 yuan to mail order an audio DAC decoding board (the board's main integrated circuit b: low noise in the experimental process: the noise of the exchange servo motor is much lower than the working noise of the hydraulic pump. It is pcm1716 + op275). It was used for motorcycle treatment and transformed into a dual circuit dual output CD/VCD player. During the transformation, the decoding board only needs to be fixed in the machine (the space in the machine is very abundant), and a series of seminars on "utilization of rubber and plastic materials" have been successfully held for 10 sessions. This machine has two groups of audio output terminals, one of which is changed to CD direct output terminal. After refitting, after repeated audition and comparison, I feel that the sound quality has been greatly improved. Both the frequency response and the dynamic performance are excellent. The music effect is far better than that of another ordinary Sanyo CD player that the author has used for many years

if you have these household appliances ready to be eliminated at home, you might as well try the method described above by the author. Although the money is not much, the results are remarkable and the fun is endless

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