Why do CRT TVs have high frequency sound?

You belong to one of the few who can hear 15 k-20 kHz high-frequency sound. If you're an adult, you're one of the lucky ones among humans, because a search will reveal that many people are worried about the upper limit of the hearing frequency of 12 kHz, or even 10 kHz or 7 kHz.

The imaging principle of CRT CRT is to use a set of coils to control the electron beam to scan quickly, the line frequency of interlacing = field frequency * vertical resolution, at this time, because of the change of electromagnetic field, the coil itself will be deformed by electromagnetic force, resulting in mechanical vibration, emitting a sound of 15 kHz. (PS: This is also the reason for the inductance acoustic noise of some computer parts, but the frequency is much lower).

Although the human hearing threshold is about 20 Hz - 20 kHz, there are significant individual and age differences. At an early age, some humans have an upper limit of auditory frequencies of 20 kHz or slightly more, <>

And as we age, our high-frequency hearing will continue to decay, and this part of the population will gradually lose this ability. Therefore, most people do not hear this frequency. Women seem to hear a little more often than men.

The day before yesterday in the supermarket, a mechanical part under the refrigerated shelves kept making a harsh high-frequency sound, and I was very uncomfortable, and I quickly ran away, but my husband, other customers around me, and the supermarket salesperson didn't feel it at all.

In reality, the high-frequency sound of the image tube night vision device is generated by the electronic bombardment of the display, and the principle is the same as that of an old CRT monitor or TV. However, the sound of the night vision device with qualified design and manufacturing quality should be very small and not affect normal use.

However, when the camera equipment is connected, the electronic rays of the picture tube can interfere with the equipment, and the recorded noise will be very obvious, especially on some products with poor electromagnetic protection. In the same way, as with the high-voted answers, headphones may also be interfered with by electronic rays to make noise. The principle of digital night vision is completely different, and the LCD LED display is generally used, which theoretically does not emit that kind of noise.

The same goes for thermal imaging cameras.

This is the sound of the high-voltage power generation circuit of the picture tube TV, an extremely slight screeching sound. The frequency is about 10,000 hertz, and above 20,000 hertz is ultrasound, which no one can hear, and whether the sound close to 20,000 hertz can be heard varies greatly between different individuals, and the proportion of children heard is higher than that of adults.

The [line output] circuit of an older CRT CRT TV set operates at 15625Hz.

Because high-frequency sound is also a part of the sound that makes up TV.

Because high-frequency sound is one of the most important ones.

Because TVs also need a lot of flat sounds.

TV because it needs a lot of channels of sound.

Because the voltage inside may be too high.

It could be a matter of voltage or current.

It is the sound of the picture tube television high-voltage circuit.

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5. Check the "Desktop Right-click Display Properties Settings Advanced Troubleshooter Hunger", adjust the "Hardware Acceleration" to "Disable DirectDraw and Direct3D", and then restart.

6. Use Windows Optimizer to clean up the registration list and solve it. Or it can be solved after reinstalling the system.

There are several cases;

1. After the IE patch is played, the flash is not updated.

2. Right-click on the desktop Properties - Settings - Advanced - Troubleshooting; There is a hardware acceleration, see if your computer hardware is accelerated, if not, tune to the next **decoding, install it.

3. Click IE Tools - Internet Options - Security - Remove the "Tick" in front of Enable Protection Mode, and enter Internet Options - Advanced Tab - Use software to accelerate graphics without using the GPU front checkmark.

4. Update flash

Liquid dust stupid crystal TV is different from traditional guess bad TV.

In this case, the display panel should be damaged, or the backlight is damaged.

If there is no image at all, there is a high chance that the power supply will be damaged.

It's better to find a professional maintenance person to repair it.

I don't have the ability to repair.

Yes, it's basically the CRT, and now it's a problem with the display.

If there is a fault, please take it to the repair shop and repair it.

Summary. My dear, if after turning on the TV, there is only some noise and no image, this situation is likely to be a problem with the high-frequency head, the middle release. According to the working principle of the TV, this reason leads to sound and no image, and the picture tube can display the machine setting menu, with sound, **interface, and can **external sound** signal.

The second situation is that there is a normal sound on a TV show, but there is no picture. This shows that the high-frequency, mid-frequency and accompanying sound circuits are in normal working condition, and there is no line output circuit without short-circuit faults.

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My dear, if after turning on the TV, there is only some noise and no image, this situation is likely to be a problem with the high-frequency head noisy sails and mid-release. According to the working principle of the TV, this reason leads to sound and no image, and the picture tube can display the machine setting menu, with sound, **interface, and can **external sound** signal. The second situation is that there is a normal TV festival of the sound of the hail in Shengzhou, but there is no picture.

This shows that the high-frequency, medium-frequency and sound circuits are in normal working condition, and there is no short-circuit fault in the output circuit.

The second case: there is a normal TV program sound, but there is no picture. This acre shows that the high-frequency, medium-frequency and sound circuits are in normal working condition, and there is no line output circuit without short-circuit faults.

If the screen can display the TV settings menu, then this kind of problem is likely to be stupid because the number of companions is separated from the video amp.

There is also a situation where the sound is normal, but there is no on-screen menu. In this way, you can turn on the brightness and contrast of the TV, pay attention to the condition of the screen, and then turn off the TV. If you see a flash of bright light on the screen at the moment of turning it off, and there is a slight discharge sound of the filial piety car, you can be sure that the picture tube is fine.

At this time, it is necessary to see whether the CRT filament is lit.

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Summary. CRT: The CRT should transmit the signal to the TV, and then through technical processing on the screen, and the CRT is the key equipment responsible for displaying the image, if it is broken, there will be no image, and the CRT needs to be replaced.

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CRT: The CRT should transmit the signal to the TV, and then put the broadcast cover on the screen through Zaofeng technology processing, and the CRT is the key equipment responsible for displaying the image.

Screen power switch:Now many smart TVs are the same as computer screens,You can turn off the screen separately,See if the screen is turned off through the power supply,Lead talk stool can be opened again。

Check whether the signal source of the TV is connected normally and stably; For example, if the TV is connected to the cable TV signal, check whether there is a problem with the cable, if the connection line is closed, there is no problem, you can switch to other channels through the car Kaiheng** Try to solve the problem;

The failure of the TV hardware causes the banquet problem, mainly because the display system of the TV has pure silver problems, such as circuit switch failure, high-voltage board failure, insufficient power supply, display screen failure, motherboard circuit, capacitor failure, and other parts may lead to no display screen.

Kiss the above traces are the picture tube TV has no image and sound reasons and treatment methods. It is recommended to contact the after-sales service of Duan Jian TV to conduct a comprehensive inspection and warranty of the TV.

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Have a great day!

General Causes and Solutions:

1. Check whether the signal source of the TV is connected normally and stably; For example, if the TV is connected to a cable TV signal, check whether there is a problem with the cable, and if the cable is fine, you can try to solve it by switching to other channels**; If the TV is connected to the *** machine or digital TV set-top box, it is important to check whether the connection line is in good contact, and the loose travel search phone can be fixed to solve it, and you can also switch channels or pictures to eliminate the problem of program sources;

2. The problem is caused by the failure of the TV hardware, mainly due to the problems of the TV's display system, such as circuit switch failure, high-voltage board failure, insufficient imitation first power, display screen failure, motherboard circuit, capacitor failure, and other component failures may lead to no display of the picture, it is recommended to contact the after-sales service of the TV for a comprehensive inspection and repair of the TV.

As soon as the machine is turned on, the screen is black, and it takes a long time to see clearly, "the stool should be cautious, the fault of this phenomenon is caused by moisture, after the picture tube base is damp, the printed circuit board is simply disturbed and conducted, so that the voltage that should be added to the second anode, sub-brightness, focusing, acceleration pole and other voltages are directly turned on (although the resistance value is very large) into the ground, and the filament is gradually heated to dispel the moisture of the tube seat and resume work. Solution: Temporary - Seat jujube to remove moisture.

Thoroughly - change the tube holder.

Hello. If there is no sound on the TV,There is no image,Then it means that it is a problem with the power supply,Check that the TV is delayed and there is a fuse next to the transformer。 It should be that the fuse is broken, so that this situation will occur.

1.If the TV has no sound or image, the screen is black, and the power indicator light is not on, it means that the TV is not powered on or the internal combustion code part is not working, you can check the external power supply, plug socket and wiring. Check the power strip inside.

2.If the TV has no sound and no image, but the blue screen or black and white snowflake noise is displayed, it means that the TV has no signal or the signal is interrupted, you can check the wiring and plug of the signal source, or re-select another source.

Change the picture tube seat, hand to the disease.

There is an image on the receiver of the picture tube TV, and the sound is not clearSolution:

First, check whether the settings are correct. First, check to see if you have pressed the mute button on the remote control. Second, check if the volume is set to the 0 position.

Again, check the signal source, the wired signal can check whether the remote control accompaniment system is in the D K system (Shen Mao Yingzhen users are in the I system); Set the set-top box or satellite receiver to turn the channel button to the left channel and check that the audio cable is connected correctly.

Second, listen to the noise. If the noise is loud due to the shift of the mid-frequency of the accompanying sound, you can change the mid-frequency of the accompaniment or fine-tune the mid-frequency of the accompaniment to restore the sound. If the noise is very small, it is not a fault of the accompanying sound intermediate frequency, check the accompanying power amplifier part, and check whether the power amplifier block or peripheral original stuffy oak can be worsened.

This fault may be caused by a deterioration in the thermal stability of a component of the circuit.

First of all, when the norm fails, measure whether the 300V voltage after rectification filtering is normal.

Measure whether the voltage of each pin of the switching power supply voltage regulation oscillation thick mode chip to the ground is normal, and whether the components around the chip are also normal.

If the inspection is normal, and the power-on test machine is not good, then focus on the measurement, high-frequency tuner circuit, and image small signal processing circuit and so on.

It is not necessarily a good thing to be able to hear the sound of electricity, some people should not be happy because they can hear the so-called "sound of electricity", this situation mostly appears in younger groups (watching TV and listening to the radio when I was a child), like us adults who wear headphones to listen to songs all year round, hearing has been damaged to varying degrees, it is best to go to the hospital to determine whether you have neurological tinnitus.

If you don't want to go to the hospital, go for a frequency hearing test (there are a lot of apps online) to see if you can hear a frequency range that the average person can't, or if you have tinnitus yourself. But be careful that your test is likely to be inaccurate, and you still have to go to the hospital.

If you are sick, hurry up and go **, don't delay your body, tinnitus is not a good sign. <>