Tips on cell phone malfunctions

1. Tips for mobile phone maintenance

1. Use a mobile phone leather case. A leather case is like adding an extra coat to your mobile phone. Firstly, it can reduce the wear and tear of the mobile phone shell. Secondly, it can reduce the damage to the mobile phone when it falls or encounters water. Of course, this does not mean that the phone will be invulnerable after adding a leather case. You must still be careful when using and placing it to avoid damage to the phone. It is best to use the original matching leather case. If not, you need to choose carefully to prevent the deviation of the two shapes from affecting the use of the mobile phone.

2. Pay attention to the environment in which mobile phones are used. There are slits or holes on mobile phones, and water vapor can easily penetrate and cause the circuit board to be corroded, so do not use the phone in the rain or in the bathroom. At the same time, be sure not to place your phone in an air-conditioning outlet, as the water vapor condensed in the phone will corrode the machine board invisibly. Moreover, the erosion of circuit boards by water vapor increases over time. It may not seem to have any impact at first, but by the time a fault occurs, it may be too late.

3. Pay attention to how you carry it. Everyone carries their mobile phone in a different way. Good carrying habits can prolong the life of the mobile phone, while some bad carrying methods will greatly increase the chance of damage to the mobile phone. For example, some friends are accustomed to putting their mobile phones in the pockets next to their pants or in the back. If they are accidentally pressed while sitting, or their mobile phones are squeezed and dropped to the ground while walking, the mobile phones will be damaged.

4. Keep your phone away from magnets. The mobile phone speaker itself is magnetic, so do not let the mobile phone frequently come into contact with iron powder to prevent excessive iron powder from being absorbed into the sound hole of the mobile phone speaker and attached to the speaker film, causing the sound from the mobile phone receiver to become smaller or even inaudible.

5. Do not use mobile phone antennas casually. Unless necessary, do not pull out the mobile phone antenna or play with it like a toy to avoid affecting the reception effect.

6. Battery maintenance. With the increase in consumer demand for communication and the emergence of various new functions of mobile phones, the power consumption of mobile phone batteries has also increased significantly. How to use and maintain mobile phone batteries has become particularly important.

(1) Master the charging time of new batteries

In the first 3 to 5 times of use, it is best to charge for 8 hours at a time, especially lithium-ion batteries, because they have strong Inertia, only after sufficient activation can the best performance be achieved.

(2) Choose the charger carefully

It is best to choose a product from the same manufacturer as the battery. When charging the battery, try to avoid sharing the same socket with other household appliances and use a dedicated socket whenever possible.

(3) Do not charge frequently.

It is best to fully discharge the battery until it is shut down before charging, and then charge the battery once. The longer the charging time, the better. When choosing a battery and charger, be sure to ask the dealer about its characteristics. For batteries without protection circuits, charging should be stopped after they are full to extend the battery life.

(4) Do not rush to charge

If the battery has been accidentally dropped or hit by heavy objects, be sure to check whether there are cracks or leaks in the battery casing to avoid ** incident occurs; if the battery has been exposed to rain or water, it must be wiped dry with a dry cloth first and placed in a ventilated place to dry by itself. Do not put it into the mobile phone for use or charging after wiping it casually to avoid short circuiting the mobile phone or battery failure* *.

Frequently asked questions about mobile phones 1. Can’t turn on the phone. During the booting process of the mobile phone, there will be a relatively complicated processing process inside it. Therefore, the reason why the machine cannot be started must be specifically checked and dealt with by the maintenance point.

2. Automatically shut down. This may be due to many reasons. For example, the battery contacts cannot be energized normally or the motherboard is abnormal. In addition, excessive static electricity can also cause the mobile phone to automatically shut down, especially in dry winter.

3. The phone freezes. If you operate the mobile phone improperly, it will also cause the mobile phone to crash. Especially when we are sending text messages, if we press the buttons too fast or are bombarded by short messages continuously in a short period of time, the CPU load of the mobile phone will be too large, and the heat generated by the CPU cannot be dissipated in a short period of time, which will cause the mobile phone to malfunction. crash.

Therefore, when we use mobile phones, we must pay attention to the operation; and try not to disclose our mobile phone numbers to avoid being bombarded by short messages. Of course, if it is for other reasons, it is better to send it to a specialized maintenance center in time.

4. It can be turned on and off, but cannot be registered to the network in geographical areas where the base station signal strength is sufficient. This fault is also one of the common faults. It involves more modular units. This type of failure will occur when there are problems with the reception, transmission, frequency synthesizer, CPU, software, etc.

Maintenance is important, but after using it for a long time, your mobile phone will inevitably have problems of one kind or another. Here, we have summarized some common mobile phone problems for everyone’s understanding.

2. Is there any basic knowledge for repairing mobile phones?

Let me categorize it.

There are basically eighteen tips for repairing mobile phones. Hope this helps! The first move: Thousand-Hand Guanyin - specializes in treating button failures 1. Failure of individual buttons: Because the buttons adopt a coordinate system, the failure of individual buttons is mainly due to surface contamination or conductive powder falling off of individual buttons, causing high and low voltage levels on the buttons. The two flat contacts cannot be connected, causing no instructions to be sent to the CPU.

Just clean the buttons or replace the conductive film on the buttons. For example: Nokia 8210, after repairing the radio frequency fault, it was found that keys 3 and 7 were malfunctioning during installation. After disassembling the phone, use a cotton swab dipped in alcohol to wash away the rosin on keys 3 and 7, and the installation was OK.

2. All buttons fail: The CPU cannot accept instructions from two buttons at the same time, so as long as one button is in a conductive state, the other buttons will no longer work. Treatment: ① Clean the buttons; ② Check and adjust the side buttons and other buttons that are easy to press.

In addition, in mobile phones such as Xiaxin A8, a varistor is connected in parallel to the high-voltage end of the button. If a certain varistor deteriorates, it will cause all the buttons to malfunction. Example: On a Shoulixin T66 mobile phone, all the keys failed, and it could not even be turned off. After disassembly and inspection, it was found that the conductive film powder on the "C" key fell on the key, causing the "C" key to "depress". Use alcohol cotton to OK after cleaning.

Tip: This type of failure mostly occurs in models with conductive film. If you have replaced the casing, pay more attention to the side buttons.

It is also necessary to correctly distinguish between a crash fault and a button failure fault. Generally speaking, if the button fails, the call can be made (can be connected but cannot be answered), but if the button crashes, the call cannot be made. 3. Row or column button failure: normal communication between the failed row or column and the CPU cannot occur.

① Check the connection between the failed row or column and the CPU. ② Solder the CPU (there should be no glue under the CPU).

Tip: Many mobile phones that use an inline socket or a cable to connect the front panel are prone to this fault. The second trick: Double thunder inertia - specializes in treating earpiece failures. Judgment: Pull out "112" and measure whether there is a jump voltage on the earpiece contacts.

① There is a jump voltage: the fault is in the earpiece or poor contact. You can clean and adjust the earpiece contacts and replace the earpiece. ② There is a jump voltage at one end and no jump voltage at the other end: it is mostly caused by a disconnection between the earpiece and the audio IC.

3. There is no jump voltage at both ends: mostly the audio IC is soldered or damaged. 4. If there is noise in the earpiece, it is mostly caused by the deterioration of the small filter capacitor on the receiving line. It can be improved by connecting a capacitor between the two poles of the earpiece.

In addition, earpiece damage and microphone failure can also cause earpiece noise, and audio IC failures can also cause earpiece noise. Tip: Many mobile phones have the audio circuit inside the power IC.

For devices with a jump voltage on one end and no jump voltage on the other, the end without a jump voltage can be grounded. The third step: pulling out the teeth from the tiger's mouth - special treatment for no transmission failure: Dial "112" and measure whether there is a voltage of about 2V at one contact of the transmitter.

① There is voltage: Most of the faults are in the microphone or poor contact. You can clean and adjust the contacts and replace the microphone. ② No voltage: The fault is mostly caused by disconnection between the audio IC and the microphone or damage to the audio IC.

You can try pulling a 2V voltage to the positive terminal of the microphone first, which can also solve some of the faults.

3. Some mobile phones have a special control tube responsible for headphone switching. If this tube is soldered or damaged, it can easily cause no call delivery.

4. The transmission noise failure is mostly caused by the deterioration of the filter capacitor, and the deteriorated capacitor can be replaced. It can also be improved by adding a capacitor between the two poles of the microphone.

Tips: There are often articles talking about how to change hands-free to solve the problem of sending and receiving calls. It is a very practical technology. The fourth trick, sharp eyes - specializes in treating display faults: Display faults have many manifestations: 1. Display missing lines - usually caused by damage to the display screen and must be replaced.

2. Sometimes the display is on and off, the screen is inverted, or the screen is blurry - for those with cables, the cables should generally be checked and replaced first; for those without cables, it is usually due to the aging of the conductive glue or the display interface. Caused by false soldering. 3. The display is black or faded - mostly caused by the deterioration of the resistors and capacitors on the display circuit. This can be improved by replacing the deteriorated capacitors and changing the contrast adjustment resistor value.

4. No display - You can use the replacement method to determine whether the fault is on the motherboard. By analyzing the cause of the fault, you can also basically determine the fault point. If you have information, you can judge by measuring whether the display voltage is normal. Tip: The display circuit is directly related to the CPU except for individual operating voltages.

Generally speaking, if the appearance of the display screen is not damaged, the possibility of damage to the display screen is very small. The fifth trick: The Glory of the Sun and the Moon - Specialized in treating no background light failure. There are two types of background lights: LED light-emitting diodes and light-emitting paper lights. The background lights of current color-screen mobile phones are also made of light-emitting diodes (white light), which are generally composed of three lights. There are more in series, and the power supply voltage is provided by the boost circuit).

For light-emitting diodes, follow the following methods for maintenance: ① If individual lights do not light up, it is mostly because the light is broken and can be replaced. ② Check whether the power supply of the background light is normal. It is usually connected to the battery voltage. If there is no flying wire.

Test the connection between the control tube and the background light. ③Add welding or replace the background light and keyboard light control tubes.

Luminous paper generally requires an AC voltage of about 150V to work properly, so it has a supporting boost conversion circuit, which consists of a boost coil, a boost conversion IC and an energy storage capacitor. The maintenance process is as follows : Use a multimeter to check whether there is an AC voltage of about 150V at both ends of the light-emitting chip. If there is, the light-emitting chip is damaged and can be replaced. If not, check whether there is an AC voltage output of 150V and an input of about 3V on the boost IC. , whether the boost inductor is damaged and whether the control signal is sent. Find the fault point by following the clues one by one.

Tip: Luminous paper is fragile. Damage to the flip phone's cable can easily cause a backlight failure, which can be solved by flying the cable or replacing it.

Failure to install a layer of reflective paper behind the color screen mobile phone display will cause the background light to be dark. (The color screen is equipped with reflective paper and light guide plates, which will affect the brightness of the backlight.)

The sixth trick: Create something out of nothing - specially designed to solve the problem of not reading the card. The SIM card or UIM card holder has six pins. First, Use the buzzer setting of the multimeter to check the counter-ground pin of the SIM card or UIM card holder. Opposite the counter-ground pin is the power supply pin, and then rotate it clockwise, which is the reset pin, clock pin, data pin, and online programming pin. ①The power supply pin generally has a 3V power supply.

In the case of disconnection, you can find a 3V voltage flying wire to force power supply. ② If the three lines of reset, clock and data are measured with a multimeter, an unstable voltage of less than 1V can be seen (can be measured with an oscilloscope if conditions permit).

If there is no one, you need to find the corresponding route and follow the clues. For GSM mobile phones, the above measurements must be taken when the mobile phone is turned on because.

3. What are the common problems and faults of smart phones? Introduction to common problems of smart phones

1. Causes of mobile phone faults GSM mobile phones do not have high voltage and high current like other household appliances. Normally Under normal circumstances, it is not easily damaged, but during maintenance, it was found that many mobile phones were sent for repair. So, what exactly caused the damage to the mobile phone? Taken together, it mainly consists of the following aspects.

1. The particularity of the surface welding technology of mobile phones. Because the installation form of mobile phone components all adopts surface mount technology, the mobile phone circuit board uses high-density composite boards, with components on both sides, and all components Mounted on both sides of the circuit board, the circuit board is fixed by the pulling force generated by the solder and the components, and the integrated chip pins of the mounted components are numerous and very dense, and there is very little solder. In this way, if you accidentally drop it or the mobile phone gets wet, the components can easily be damaged. Faulty soldering or poor contact between components and circuit boards can cause various malfunctions in mobile phones. 2. Mobility of mobile phones Mobile phones are personal consumer goods. They need to move with the change of the user's position, which requires the mobile phone to adapt to different environments. Although designers have specially designed the adaptability of mobile phones, they still cannot avoid the problem. Various malfunctions of the mobile phone may occur due to prolonged use or improper ambient temperature.

Its main manifestations are: first, water and moisture enter, causing components to be corroded, the insulation level to decrease, and the control circuit to lose control, causing the logic system to work disorderly, the software program to work abnormally, and in severe cases, the mobile phone will not turn on. . Second, it is affected by external forces, which manifests as desoldering, falling off, and poor contact of components.

3. Improper user operation It is very common for mobile phones to lock up and cause functional disorders due to improper user operations. For example, if the mobile phone menu is operated randomly and some functions are turned off, the mobile phone cannot be used normally; After incorrectly entering the password causes the phone and SIM card to be locked, blind attempts will result in locking the phone and SIM card. In addition, improper menu settings can also cause some "inexplicable" failures. For example, if there is no response to incoming calls, it may be that the owner has set the call forwarding function; if the phone cannot make a call, it may be that the outgoing call restriction function has been set.

This requires maintenance personnel to be familiar with the various functions of GSM mobile phones and the operation and use of the mobile phones to be repaired. 4. Improper maintenance by the repairer. A considerable number of mobile phone failures are caused by improper operation, random disassembly, and random welding by the repairer.

If you are not careful when blow-soldering integrated circuits, the surrounding small components will be blown away. Excessive force may cause cracks and deformation of mobile phone components. Nowadays, some new mobile phones mostly use BGA packaged integrated circuits. Some repairers with low welding skills and irresponsible people always want to "practice their skills" here. The consequences can be imagined.

In addition, when some mobile phone repairmen repair mobile phone software faults, they only look at the mobile phone model and not the mobile phone version. As a result, they enter the wrong software, causing more complex faults. For example, the Siemens 2588 mobile phone is more likely to have a lock failure, but the same 2588 mobile phone has many versions. Different versions have different unlocking software and methods. If the maintenance personnel do not check the version before unlocking, the consequences will be would be "catastrophic".

5. Improper use and maintenance. When using the keyboard of a mobile phone, touching the keys with the tips of fingernails will cause the keyboard to become bald or even fall off. Charging with an inferior charger will damage the charging circuit inside the mobile phone and even cause an accident. Mobile phones are very sophisticated high-tech electronic products. When using them, you should pay attention to using and storing them in a dry and temperature-friendly environment.

Otherwise, it is very easy to cause failure. 6. Congenital defects: Some parallel-imported mobile phones are assembled and modified and are of low quality.

Although some mobile phones are also digital mobile phones, they do not comply with GSM specifications and are therefore prone to malfunctions. 2. Repair steps and procedures for mobile phone faults (1) Fault classification Without disassembling the mobile phone, the faults can only be seen from the appearance of the mobile phone, which can be divided into three major types: 1. The first type is that it cannot work at all, including the inability to turn on the phone. , nothing happens when pressing the power switch of the phone after connecting it to the power source.

The second type is that the phone cannot be turned on completely. After pressing the power switch of the phone, the current can be detected, but there is no normal boot message: such as the button lighting and display lighting are all on, and there is character information on the display. It shows that the ringer has a tone indicating that the self-test has passed after powering on. The third type is that it can be turned on normally, but some functions are malfunctioning, such as the buttons are not working, the display is abnormal (character prompts are wrong, the screen is black, the characters are unclear), there is no sound, and the call cannot be sent, etc.

2. Disassemble the mobile phone and look at the faults from the mobile phone movement. It can also be divided into three major types: namely, power supply, charging and power supply failure, software failure and transceiver path failure. These three types of faults are inextricably linked. For example, mobile phone software faults affect the power supply part, the phase-locked loop circuit of the transceiver path, the transmit power level control, the time-sharing synchronization of the transceiver path, etc., and the reference of the transceiver path The crystal oscillator also provides the running clock signal for the mobile phone software to work.

3. According to the nature of the fault, it can be divided into the following five types: no boot fault, no network access fault, no card recognition fault, no display fault and other faults. 2) Basic maintenance environment 1. The first thing you need is a quiet environment, do not perform maintenance in a noisy place; 2. Spread a thick black rubber sheet for insulation on the workbench; 3. Prepare a small The component rack of the drawer can be used to store corresponding accessories and parts during the disassembly process. Prepare a work desk lamp, magnifying glass or microscope, soldering iron, multimeter, voltage regulator and oscilloscope; 4. Be sure to connect the ground wires of all instruments. together to prevent static electricity from damaging the CMOS circuit of the mobile phone; 5. Every time before disassembling the machine, touch the ground wire twice to discharge the static electricity on the human body. Pay attention to your clothing and do not wear chemical fiber and other clothing that easily generates static electricity for repairs. ; 6. Do not burn the soldering iron in the air for a long time. This will aggravate the oxidation of the soldering iron tip and make it difficult to use the soldering iron.

When using a soldering iron to solder integrated circuits, you should use the residual heat of the soldering iron to solder. That is, after heating, unplug the soldering iron and solder again. 3) Precautions before repairing Before repairing a mobile phone, you should pay attention to the following matters: 1. A mobile phone is a microelectronic product of integrated circuits. Integrated circuits are precision and are developed through advanced technology. Maintenance personnel must understand each The performance of chips and components, understanding the logical connection of the circuit, conducting circuit analysis, careful inspection, correct judgment, fast and accurate operation, to avoid misjudgment, causing.

Man-made failures cause economic losses. Ask the user if it has been repaired before, and if so, ask.

4. Tips for mobile phone maintenance

1. Use a mobile phone holster.

A leather case is like adding an extra coat to a mobile phone. Firstly, it can reduce the wear and tear of the mobile phone shell. Secondly, it can reduce the damage to the mobile phone when it falls or encounters water. Of course, this does not mean that the phone will be invulnerable after adding a leather case. You must still be careful when using and placing it to avoid damage to the phone.

It is best to use the original matching leather case. If not, you need to choose carefully to prevent the deviation of the two shapes from affecting the use of the mobile phone. 2. Pay attention to the environment in which mobile phones are used.

There are slits or holes on mobile phones, and water vapor can easily penetrate and cause corrosion of the circuit board, so do not use the phone in the rain or in the bathroom. At the same time, be sure not to place your phone in an air-conditioning outlet, as the water vapor condensed in the phone will corrode the machine board invisibly.

Moreover, the erosion of circuit boards by water vapor increases over time. It may not seem to have any impact at first, but by the time a fault occurs, it may be too late. 3. Pay attention to how you carry it.

Everyone carries their mobile phone in a different way. Good carrying habits can extend the life of the mobile phone, while some bad carrying methods will greatly increase the chance of damage to the mobile phone. For example, some friends are accustomed to putting their mobile phones next to their pants or in their back pockets. If they are accidentally pressed while sitting, or their mobile phones are squeezed and dropped to the ground while walking, it will cause damage to the mobile phones.

4. Keep your phone away from magnets. The mobile phone speaker itself is magnetic, so do not let the mobile phone frequently come into contact with iron powder to prevent excessive iron powder from being absorbed into the sound hole of the mobile phone speaker and attached to the speaker film, causing the sound from the mobile phone receiver to become smaller or even inaudible.

5. Do not use mobile phone antennas casually. Unless necessary, do not pull out the mobile phone antenna or play with it like a toy to avoid affecting the reception effect.

6. Battery maintenance.

With the increase in consumer demand for communication and the emergence of various new functions of mobile phones, the power consumption of mobile phone batteries has also increased significantly. How to use and maintain mobile phone batteries has become particularly important.

(1) Master the charging time of the new battery. It is best to ensure that it charges for 8 hours in the first 3 to 5 times of use. Especially for lithium-ion batteries, because they are very inert, they can only be charged for 8 hours. Only after activation can the best performance be achieved. (2) Choose the charger carefully. It is best to choose a product from the same manufacturer as the battery.

When charging the battery, try to avoid sharing the same socket with other household appliances and use dedicated sockets whenever possible. (3) Do not charge frequently. It is best to fully discharge the battery until it is shut down before each charge, and charge it fully at one time.

The longer the charging time, the better. When choosing a battery and charger, be sure to ask the dealer about its characteristics. For batteries without protection circuits, charging should be stopped after they are fully charged to extend the service life of the battery. . (4) Do not rush to recharge the battery. If the battery has been accidentally dropped or hit by heavy objects, be sure to check the battery shell for cracks or leaks to avoid accidents; if the battery has been exposed to rain or water, Be sure to dry it with a dry cloth first and place it in a ventilated place to dry by itself. Do not put it into the mobile phone for use or charging after wiping it casually to avoid short circuiting the mobile phone or damaging the battery.

Frequently asked questions about mobile phones 1. Can’t turn on the phone. During the booting process of the mobile phone, there will be a relatively complicated processing process inside it.

Therefore, the reason why the machine cannot be turned on must be specifically checked and dealt with by the maintenance point. 2. Automatic shutdown.

This may be caused by many reasons. For example, the battery contacts cannot be energized normally or the motherboard is abnormal.

In addition, excessive static electricity can also cause the mobile phone to automatically shut down, especially in dry winter. 3. The phone freezes.

If you operate the mobile phone improperly, it will also cause the mobile phone to crash. Especially when we are sending text messages, if we press the buttons too fast or are bombarded by short messages continuously in a short period of time, the CPU load of the mobile phone will be too large, and the heat generated by the CPU cannot be dissipated in a short period of time, which will cause the mobile phone to malfunction. crash.

Therefore, when we use mobile phones, we must pay attention to the operation; and try not to disclose our mobile phone numbers to avoid being bombarded by short messages. Of course, if it is for other reasons, it is better to send it to a specialized maintenance center in time.

4. It can be turned on and off, but cannot be registered to the network in geographical areas where the base station signal strength is sufficient. This fault is also one of the common faults.

It involves more modular units. This type of failure will occur when there are problems with the reception, transmission, frequency synthesizer, CPU, software, etc.

Maintenance is important, but after using it for a long time, your mobile phone will inevitably have problems of one kind or another. Here, we have summarized some common mobile phone problems for everyone’s understanding.

5. What basic knowledge you need to know about mobile phone maintenance

Section 1 Measuring instruments 1.1, identification and use of multimeters 1.2, measurement and use of DC regulated power supply 1.3. How to use analog oscilloscope 1.4. Identification and use of spectrum test analyzer Section 2 Use of maintenance tools Instruments use hot air guns, soldering stations, maintenance power supplies, software maintenance tools, tin planting plates, solder paste, scrapers and tweezers , Tips on using screwdrivers of various specifications in mobile phone repair.

Use various tools flexibly and skillfully to complete the repair with the simplest tools and the least operations. Section 3: Mobile phone desoldering skills 3.1, small component desoldering skills 3.2, QFP flat package desoldering skills 3.3, BGA desoldering skills 3.4, sealing Glue IC desoldering skills 3.5, BGA foot disconnection and flying wire skills 3.6, how to deal with circuit board bubbling Section 4 Computer operating knowledge 4.1, various operating precautions on the computer 4.2, installation and installation of various mobile phone repair software Application 4.3, operations of flashing, modifying, unlocking, etc. Section 5 Mobile Phone Software Maintenance 5.1, Overview of Maintenance Instruments 5.2, Selection of Mobile Phone Software Maintenance Instruments 5.3, Application of Programmers in Mobile Phone Maintenance Practice 5.4, Various Mobile Phone Software Maintenance Thoughts Section 6 Featured Operations 6.1. Chip maintenance: Exclusive three-level chip maintenance in Southwest China; disassembly and assembly skills for Nokia, Sony Ericsson, Motorola and other chips 6.2. Mobile phone radio frequency (no network and no signal) maintenance methods provide powerful technology for opening a store Support, Competitive Advantage Section 7 Specific Practice 7.1, Waveguide Star King Series Mobile Phone Circuit Principle 7.2, Ericsson Series Mobile Phone Practical Operation 7.3, Nokia Series Circuit Analysis, Practical Operation, Welding Operation and Various Practical Troubleshooting and Fault Summary 7.4, Samsung /Philips series circuit analysis, practical operation and troubleshooting 7.5, Siemens/Panasonic series circuit analysis, practical operation and summary 7.6, Motorola series circuit analysis, case analysis, practical operation, welding practice and various troubleshooting 7.7, Sony Ericsson/Waveguide Series of troubleshooting 7.8, practical operations of various maintenance techniques such as flashing, upgrading, jailbreaking, and cracking of iPhones and troubleshooting of various problems 7.9, circuit analysis, practical operations and troubleshooting of 3G mobile phones 7.10, various other common models and brands of mobile phones Learning maintenance technology

7.11. Learning the maintenance technology of various other domestic mobile phones and copycat mobile phones. 7.12. Practicing the disassembly and assembly of various clamshell machines, candy bar machines, slide machines, PDAs, and handheld computers. 7.13. Practicing various When welding electronic components, we must be proficient in welding, with no false soldering, no blown electronic components 7.14, no dropped points, no disconnection, use the simplest tools and operations to remove glue 7.15, and practice welding and replacing cables. Skills 7.16. Practice various flying line skills. 7.17. Operate various instruments with your own hands to complete maintenance work, be proficient in using them, and use the most ingenious methods and the simplest instruments to achieve the best results. 7.18. Computer operation, use the computer to flash the mobile phone. , software installation, unlocking and a series of tasks 7.19. Able to accurately and quickly identify mobile phone faults 7.20. Personally receive customers who come to your door, complete a series of operations from order taking to maintenance, master various business skills, and achieve the ability to open a store independently.

You can check here for more details

6. What are the analysis and solutions to common mobile phone faults

First, prevent water from entering the mobile phone. Once the mobile phone is flooded, you should remove the battery first and do not turn it on to test whether it can be used, because more serious damage will be caused after powering on the phone.

The casing should be wiped with a dry cloth, and the fine cracks in the panel should be dried with a hair dryer, and sent for repair as soon as possible. Second, if you are not familiar with the password setting function of your mobile phone, do not set passwords at will. Some password settings cannot even be opened by repairmen and operators. Moreover, entering the wrong password multiple times may cause the phone card to be destroyed. Even if the card number is Even if you buy it back, the information on the original card cannot be restored.

Third, the mobile phone screen is also very important. Its value accounts for more than one-fifth of the total value of the mobile phone. Especially for mobile phones with touch screen, handwriting and other functions, do not rub the screen with your hands frequently, because the screen has a very thin sensing coating, and if it is damaged by friction, it will affect the handwriting function.

There are also some men who are accustomed to using hard-shell mobile phone cases, but be careful not to point the phone screen towards the buttons of the mobile phone case, because the metal buttons can easily break the screen. In addition, there are some so-called malfunctions caused by users not understanding the functions of their mobile phones and mistakenly setting certain functions.

For example, if you cannot hear the other party's voice, you may have turned off the receiver sound; if you cannot answer the call, you may have turned on the reject all incoming calls function; if your phone automatically shuts down at a certain time, it may be The user has set a scheduled shutdown, etc.

7. What are the common problems and troubleshooting methods of Android mobile phones?

Common problems and troubleshooting methods of Android mobile phones: Fault 1: The mobile phone cannot be turned on. Solution: Some people’s new mobile phones After upgrading or restoring factory settings, put in the battery and turn on the phone for the first time. The phone needs to be initialized and the boot time is relatively long. At this time, people will mistakenly think that their phone cannot be turned on. If the phone does not turn on due to excessive battery discharge, remove the battery. , connect the mobile phone to the charger to see if it can be turned on. If it can be turned on, put the battery in and charge it for more than 30 minutes before it can be turned on normally.

Fault 2: The mobile phone is placed in the pocket, and the touch screen is in contact with the body. At this time, when a call comes, there is a probability that the touch screen cannot be swiped to answer the call. Solution: To keep the mobile phone screen clean and dry, click twice to turn on the phone. button (lock screen button) to allow the touch screen to recalibrate itself; Fault 3: Oil or water on your hands or touch screen causes the touch screen to malfunction. Solution: Wipe the surface of the phone dry with a dry cloth, and press the power button (lock screen button) twice. ) to allow the touch screen to recalibrate itself; Fault 4: The mobile phone touch screen fails when the mobile phone charger is plugged in. The noise signal of the charger has the same frequency as the signal frequency of the capacitive touch screen, resulting in TP failure. Solution: 1. Unplug the charger; 2. Press twice Press the power button; 3. Unplug the charger, remove the battery, and use Huawei's standard charger; Fault 5: The phone restarts or automatically shuts down when some unstable software is installed on the phone. Solution: Smartphones are the same as ordinary ones. The biggest difference between feature phones is that they have their own systems. Some third-party software installed on the phone may cause the phone to restart or crash, restore factory settings or uninstall software that is incompatible with the phone; Fault 6: During charging or use How to deal with hot mobile phones: It is normal for this situation to occur. After all, Android phones have so many functions and everyone spends more time on their mobile phones. This is a normal phenomenon, but it also depends on personal use. For example, avoid charging or using for a long time in an environment exposed to direct sunlight, close unused background programs, and it is best not to play games or make phone calls while charging.

Fault 7: It feels like the phone’s standby time is short. Solution: How to extend the standby time has always been a common problem for Android phone users. For example, fully charge before going out, turn on the power saving mode of the phone, and use WLAN or Bluetooth when not in use. , GPS or data services, please turn off the corresponding functions and turn off unused software (Settings - Applications - Running services, turn them off).