Shulou(Shulou.com)05/31 Report--

Hello everyone, Lin Fei to answer the above questions, Nokia 1680c how to set lock screen time, Nokia 1680c battery many people do not know, now let's take a look!

1. Nowadays, most people can't do without their mobile phones. Not to mention a day, many people can't do it in an hour. And it is commonly used not only by young people, but also by children and old people. Although mobile phones are widely used, people's understanding of mobile phones is not deep enough, and many problems can not be solved by themselves. For example, many people are very anxious when their cell phones are not turned on, but they don't know what to do. Today, Bian Shaw will introduce to you the possible reasons and solutions for the failure to turn on the Nokia 1680c.

2. Why didn't Nokia 1680c start up

3. First, the boot line is not normal. Under normal circumstances, when the boot key is pressed, the trigger voltage of the boot key should change significantly. If there is no change, it is usually due to poor start-up key contact or broken boot line, and components are welded or damaged. During maintenance, use an external power supply to observe the changes of the ammeter. If the ammeter does not respond, it is usually the starting circuit or the starting key that is broken.

4. Second, if the mobile phone does not turn on due to abnormal power supply ic, it should work normally, and the power supply circuit should output normal voltage to supply power to the load circuit. In the power supply circuit, the circuit ic is its core circuit, different types and types of mobile phones have different power supply modes. Some power circuits are powered by several voltage regulators, while others are directly powered by a power module, such as Motorola phones and Nokia phones. However, if the power supply ic is not working properly, the phone may not be able to power on.

5. Third, the battery and part of the power supply circuit are not turned on. For most mobile phones, the power supply voltage is directly added to the power supply ic after adding a battery or an external power supply. If the power supply voltage is not added to the power supply, it must be converted by an electronic switch and then added to the power supply ic. In other words, there are two ways for mobile phone power supply: one is battery, and the other is external interface power supply (when the mobile phone charging base is powered on). When two power supplies are supplied at the same time, the external interface power supply is preferred. The switching of the two power supplies is controlled by electronic switches, which mainly protect the current of the whole machine and prevent the internal ic of the mobile phone from being damaged by short circuit or leakage. However, if the electronic switch is damaged, the module may not get the power supply voltage of the battery, causing the phone to fail to start. For the mobile phone powered by this kind of electronic switch, it can be triggered by battery, powered by external power interface, or powered by external power supply. During maintenance, different power supply modes can also be used to distinguish the fault range and judge whether the electronic switch is normal or not.

6. 4. The system clock and the system clock which is not opened because of abnormal reset is one of the conditions for the normal operation of cpu. The mobile phone system usually uses 13mhz. The 13mhz clock is abnormal, the logic circuit does not work, and the phone cannot be turned on. The 3mhz clock signal should reach a certain amplitude to stabilize the vibration of the 13mhz clock circuit. After that, it is necessary to ensure that the 13mhz clock signal can be input to the cpu pin through the resistor, capacitor and amplifier circuit. Test the cpu clock input pin. If not, check whether the resistors, capacitors and amplifiers in the circuit are underwelded or have no power supply or damage. Resrt signal is also one of the working conditions of cpu. The symbol is rst, abbreviated as RST, and is represented by purx in Nokia phones. Reset is generally directly from the power supply ic to cpu or the use of a special reset small integrated circuit, the reset exists at the moment of startup.

7 、 5. Due to the abnormal logic circuit, the logic circuit is not open. The focus of the logic circuit is to overhaul the cpu chip selection signal ce and the allowable signal oe for each memory. These signals are important, but the key is to find them. As more and more mobile phone circuits use bga encapsulated integrated circuits, it is necessary to find these signals and their measurement points. The chip selection signal is a pulse signal that beats up and down. The mobile phone often causes the board to deform when it is in use. Some chips will be soldered due to external forces such as buttons and bumps. In general, repairing or resoldering these chips will solve most of the problems. When the normal chip cannot be turned on by re-soldering or replacement, the reading

8. VI. The software is not normal. When the phone is turned on, if there is something wrong with the software, it will not turn on. The software error is mainly due to abnormal memory data. If the line is not obviously disconnected, you can first replace the normal chip, version, or rewrite the software. Some on-chip circuits can be damaged, but the software cannot rewrite them. When rewriting the software, the original data should be saved for emergency repair.

Nine, seven. There are many reasons for the unsuccessful startup of the mobile phone due to other reasons, such as poor LCD screen and short circuit of components (especially power amplifiers), which may cause the mobile phone to fail to boot. Some models must use 32. The real-time clock of 768khz is used as chip clock signal and dormant clock signal. If 32. An abnormal real-time clock in 768khz may also cause the phone to fail to power on. Reference 32. The main abnormal factors of 768khz clock are clock, backup battery short circuit, 32. The 768khz clock is broken and so on. Therefore, when the mobile phone is not turned on for maintenance, it is necessary to analyze the specific circuit. As long as the principle of the mobile phone is understood correctly and the train of thought is clear, the fault that does not turn on can be eliminated generally.

10. Nokia 1680c non-boot solution

For us users, all we can do is to check whether the reason for not turning on is because of a power outage. If the phone has power but is not turned on, it should be sent to the repair shop for repair. Of course, if many people can operate on their own, they can also solve the problem according to the above reasons. For mobile phone maintenance personnel, some common faults of fixed circuits need to be analyzed and recorded. After all, nothing will change, and we can calmly deal with different models of machines with the same circuit in the future.

12. The above is what Bian Xiao introduced to you today, the reasons why Nokia 1680c does not turn on and its solutions. I believe you should know what to do after reading it. In real life, many people are used to slapping because it is useless to touch their mobile phones, and some people even clap hard to see if they can get back to normal, which is harmful to mobile phones. Therefore, in the future, if the Nokia 1680c is not turned on again, it will still be sent to the repair shop. If it is still under warranty, it can be sent back to the manufacturer for maintenance.

At the end of this article, I hope it will be helpful to you.

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