Please check the signal cable when the digital TV appears, and the frequency lock is not successful.

It is estimated that a certain joint of the digital TV line (the most common is the connection line between the TV and the TV box on the wall) is not in good contact, which causes some abnormal frequency indicators, and the bit error rate of the set-top box is too high to be analyzed.

Workaround: Turn on the TV and set-top box:

1. If the TV screen shows the image of the set-top box and then prompts "no signal", this phenomenon proves that the audio line (red, yellow, white) connection between your set-top box and the TV is basically fine.

The TV RF input signal cable (note: not the red, yellow and white) is not connected to the RF input port of the set-top box.

The TV RF input signal cable is not connected to the terminal box on the wall.

Other places where the circuit is broken.

2. If the TV screen does not appear as the opening image of the set-top box, and then it is only a blue screen without any text prompt, it means that there is a problem with the channel setting of the TV.

3. Check the power light in front of the set-top box first, if it is not on, check whether the power plug of the set-top box is plugged in (make sure the socket is powered) or check whether the switch of the set-top box is open.

Generally, it is caused by poor antenna contact or poor signal of the antenna; Call your local cable TV operator for repair, and they will come to your door for free to repair the drops.

The reason for the failure of the digital TV signal locking is the weak TV signal.

Whether the ** cable of the TV is not connected well or plugged in the wrong position, it is recommended to reconnect it correctly according to the wiring instructions; Whether it is the ** input source of the TV is not correct, switch the signal source in the remote control, such as connecting to cable TV, switch to cable TV (or radio frequency signal) input, if it is connected to a set-top box or digital TV, you can use an HDMI cable to connect and adjust the TV input signal to HDMI.

If the power indicator of the TV is off, it may be that there is a problem with the power connection of the TV, resulting in a sudden power failure without an image, such as the power plug is loose, the power source line is faulty, etc., you can check the problem one by one and deal with it accordingly.

If the power indicator of the TV is on, it may be that the standby button of the remote control has been pressed by mistake, so that the TV enters the standby state, and there is no image displayed, you only need to press the standby button of the remote control again, and the TV can be woken up and the normal screen display can be restored. Check that the network cable is not connected, connect the network cable to the WAN port of the video terminal, check whether the service network is faulty, and contact the corresponding Yunzhi operator for verification.

I guess the TV signal strength can't reach the minimum strength of the signal received by the set-top box, you can look up the menu, look at the page of a certain channel version information. Look at the signal strength and quality display,Compared with another set-top box for TV,Is it a little worse。

If the signal strength is weak, (this TV effect is worse than the other when the analog signal is analog), try to distribute the incoming signal with a power divider or room amplifier, rather than simply using a tee or something like that. Increase signal strength.

I have not tried these methods of power, just guessed according to theory, for reference only, please let the professionals handle it with caution. Or there may be other reasons, throw bricks and bricks here, please point out.

Generally, different models of digital TV set-top boxes have different unlocking passwords; You can try to unlock it as follows:

1. Check the instruction manual of the set-top box first, there is generally an unlocking method, and you can unlock it according to the method in the manual;

2. If there is no manual, try to enter 0000 or 1234 in the unlock password input box to unlock, which is the default unlock password of most set-top boxes;

3. If it still can't be unlocked, you can try to restore the set-top box to factory settings to unlock it: press the menu button to find the system settings, find the system restore after entering, and press the confirm button to restore the system of the set-top box to the factory settings state to restore it to normal;

4. If none of the above methods can be unlocked after trying, it is recommended to contact the customer service of the set-top box in time and unlock it according to the unlocking method told by the customer service; Or the customer service arranges a professional to come to the door to operate and unlock.

With the increase of the screen in the display device, the transmission line will not only grow accordingly, but also bend in many places, which makes the consistency of the transmission line itself worse, resulting in a large attenuation of the signal in the transmission process, that is, the eye diagram corresponding to the signal.

Variation, including eye width narrowing and eye height becoming low, and then make the display screen driver chip 200 unable to identify this signal because of the received signal probabilistic error, causes signal transmission to lose lock, and the phenomenon that the display equipment works abnormally.

The user increases the amplitude of the output signal of the front-end motherboard chip 100 in advance, so that the eye height corresponding to the signal is higher, and increases the strength of the high-frequency component of the output signal of the front-end motherboard chip 100 in advance, and makes it maintain a large margin, so that the eye width corresponding to the signal is wider.

Generally, there are two lights on the front panel of the cable TV set-top box, one is the power light, and the other is the signal lock light, the power light is on after the power is turned on, the lock light flashes, and the lock light is on after the light signal is locked. If the lock is lost, contact their customer service and install the master to deal with it.

1. The main reason is that the TV signal connected to the digital TV is not good or the signal is interfered with by the outside world, resulting in the failure to lock the frequency.

2. Solution: Replug the signal input cable, remove the interference sources around the set-top box or TV, such as induction cooker, refrigerator, electric fan and other electrical equipment, and then restart the set-top box. If the problem persists, it may be caused by a problem with the signal transmission link or server of the TV service provider, and you can contact the service provider for troubleshooting and repair.

The signal at that frequency is not good, or there is interference.

For example, the 379 frequency point cannot be locked, and there may be a signal on the adjacent analog channel frequency.

Possible reasons why the digital TV set-top box is locked and the signal light does not light up:

1. The signal cable connecting to the set-top box has been dropped.

Solution: You need to reconnect the signal cable to restore the signal.

2. The signal demodulator of the set-top box is broken.

Solution: Ask a professional to replace the signal demodulator.

3. The front-end of radio and television will suspend and adjust individual programs, so that the programs that appear cannot be watched.

Solution: Wait for the radio and television to complete the modification.

There are two lights on the front panel of the cable TV set-top box, one is the power light, and the other is the signal lock light, and the power light is on when the power is turned on, and the lock light flashes. After the light signal is locked, the locking light will stay on, and if it is unlocked, the locking light will not be on.

General Causes and Solutions for Cable TV Suddenly Showing No Signal:

1. If the connection line between the cable TV set-top box and the TV is loose and the contact is poor, resulting in the loss of signal, you can check the connection line, reconnect it correctly, fix it, and be cautious.

2. The user misoperates, switches the signal source of the TV to other modes, resulting in no signal display, you can press the signal source key of the TV to switch the signal source mode one by one, until the picture of the cable TV is restored.

3. The signal is lost due to the failure of the external cable TV signal transmission line or the server failure of the service provider, and it is necessary to wait for the service provider to repair before it can be restored to normal.

4. The hardware failure of the set-top box or TV causes a sudden loss of signal, which needs to be repaired by contacting the corresponding after-sales service to solve it.

With the increase of the screen in the display trapped equipment, the transmission line will not only grow accordingly, but also will appear in many bends, which makes the consistency of the transmission line itself deteriorate, causes the signal to produce a large attenuation in the transmission process, that is, the eye diagram corresponding to the signal becomes poor, comprises the narrowing of the eye width and the eye height becomes low, and then the display screen driver chip 200 cannot identify the signal because of the probability error of the received signal, causes the signal transmission to lose lock, and the phenomenon that the display equipment works abnormally.

The user increases the amplitude of the output signal of the front-end motherboard chip 100 in advance so that the eye height corresponding to the signal is higher, and increases the strength of the high-frequency component in the output signal of the front-end motherboard chip 100 in advance, and makes it maintain a large margin, so that the eye width corresponding to the ear of the signal is wider.