Disassemble mobile phone and place it on a PCB holder. Using a multimeter, check track and find the fault or the missing track that need jumper. Apply liquid soldering flux to the points where you need to solder jumper wire.
Cut jumper wire to desired length and remove its lamination using blade cutter. Hold one end of the jumper wire and solder it to one point of the faulty circuit track. Use a good quality tweezers to hold the wire and good quality of soldering iron and solder wire to solder. Now hold the other end of the jumper wire and solder to the other point of the track 7. Using a multimeter check the jumper.
In this example, the jumper is the white block covering two of the three gold pins. Also, next to the pins is a silkscreen description of what the pins do, in this case when pins are jumped the computer is operating normal, when are jumped it is set into configuration mode, and when open the computer will be in recovery mode. Figure Jumper Setting You now know the skills that you need in order to diagnose and repair a mobile phone.
Let us now learn how to diagnose and repair mobile phones. Mobile Phone Diagnosis There are two methods that you can use to find out faulty or damaged components in a mobile phone. During cold testing do not power the phone from any equipment. Use the diode range and beep sound from the multimeter to find fault in the mobile phone.
During the fault-finding and repairing process of each part, component or section, you should receive the following correct values: 1. Battery Connector Tip Sense : above. Display Connector Supply Pins:.
Display Connector Signal Pins:. Camera Connector Supply Pins:. Camera Connector Signal Pins:. Key Tip Row and Column :. Charger Connector Tip:. Vibrator Motor Connector:. Micro Card Connector Pin 1,2,3,5,7, The fault is found by powering the mobile phone with a battery which has a DC power supply. During hot testing, the voltage of different part or sections should be as follows all values in Volt : 1.
Display Connector Supply Pins: 1. Display Connector Signal Pins when working:. Camera Connector Supply Pins: 1. Camera Connector Signal Pins when working:. Charger Connector Tip: 5 to 6 Vibrator Motor Connector Tip when Working: 1. Micro Card Connector Pin 1,2,3,5,7,8: 0 to 2. The following statements describe either the cold testing or hot testing methods used for diagnosing mobile phone problems.
Write the correct diagnosis method against the statement that best describes it. Description of diagnosis method Name of Diagnosis method 1. Checks the value of resistance using a multimeter to diagnose a problem 2. Checks the voltage of damaged part by giving power to the mobile phone using a batter of DC power. The phone is not powered during testing 4.
Fault is found by powering the mobile phone with a battery Compare your answer with what you read in the following section. You now know how to diagnose a fault in a mobile phone using the hot and cold testing method.
In the next section we shall learn about the common mobile phone faults. A fault is a defect a failure in a circuit or an electronic device. What causes faults or failures in mobile phones? Solutions to Battery charging faults 1. Change the charger and check. The voltage must be between 5 and 7 Volts. Clean, resold or change the charger Connector. If the problem is not solved then change the battery and check again 5. Check the voltage of the battery connector using a Multimeter.
The voltage should be between 1. If there is no voltage in the connector check the track of the charging section. Refer to the diagram of the particular model of the mobile phone. If the problem still persists, check the fuse, coil and regulator one by one and change the faulty part. If the problem is still not solved then heat or change the charging IC.
Finally heat, re-ball or change the Power IC. Check the battery connector and charger plug to see if there is any problem. Check if there is any dust or corrosion in the connector or any broken pin. Clean the points using IPA or cleaning swabs. Check the Interface Connector to see if there is any dust. If there is dust clean or replace the interface connector. If the battery problem is not solved then upgrade the software or operating system to latest version 5.
Check for any short circuit. If there is serious problem at the board level then it is better to replace the whole Logic Board of the Mobile Cell Phone. Solutions to Network fault 1. Manually search for the network. Repair or replace it. If the network resumes after manual search but the home network cannot be selected, then there is a problem with the PFO.
Repair or change the PFO. If the Network gets disconnected during phone calls then you should repair or change the Network IC. Clean the antenna tips and point.
If the network problem persists, heat or change the 26MHz Crystal Oscillator. If the problem is still not solved then heat or change the Antenna Switch. You can also jumper if the Antenna Switch is not available.
Heat, re-ball or change the Network IC. Heat, re-ball or change the Power IC. Heat, re-ball or change the CPU. Take Note: If the problem is not solved by hardware interventions, then reload the PM File in the mobile phone using the software box.
Check the SIM Card. Alternatively, try to insert another SIM card inside the mobile phone that has the network problem. If the problem is caused by the SIM card, then you should change or replace it.
If the problem is still not resolved then upgrade the operating system to the latest version. If the problem is not solved then you may have to change the mobile phone. Mobile Phone Overheating A mobile phone may overheat either inside or on the body.
To solve this problem you should proceed as follows: 1. Check if the mobile phone overheats when a particular application is running or if the overheating happens all the time.
Upgrade the mobile phone software operating system to the latest version. This may solve the overheating problem. Close all the applications and try to run 1 application at a time 4. If overheating persists, then there is some internal hardware problem.
Earpiece or Ear Speaker Problem The Earpiece or speaker is the electronic component or part that helps us to listen to sound during a phone call. See Figure 27 for a picture of an ear speaker. How to Solve Earpiece or Speaker Fault 1. Check the speaker volume during a phone call. If speaker volume is fine, then check the earpiece by keeping the multimeter in buzzer mode.
If the problem is not solved then check the Circuit Track of the earpiece section. Do jumper wherever required. If the problem is still not solved then heat, reball or change the CPU. Take Note: If the sound is low or not clear during a phone call, then you should change the speaker.
Ringer Problem A Ringer is any type of electronic component that rings or plays a loud sound. It is also called the I. F Speaker, buzzer, melody, etc. Figure 28 shows a picture of a ringer. Check the ringer settings in the mobile phone. Check Ringer volume and silent mode. If the problem is not solved then open the mobile phone and clean the ringer point and ringer connector.
If the problem is not solved then check the ringer by keeping the multimeter in buzzer mode. If the problem is not solved then check the track of ringer section. If the problem is not solved then check the Ringer IC. Heat or change the IC.
Vibration Problem The vibrator is an electronic device that generates vibrations. How to solve Mobile Vibrator faults 1.
Check the Vibrator settings in the mobile phone. If the problem is not solved then open the mobile cell phone and clean the vibrator tips and connector. If the problem is not solved then check the vibrator with the multimeter in Buzzer Mode. If the problem is not solved then check the track of the vibrator section.
Microphone Problem The Microphone is an electronic component that helps to transmit sound during phone call. How to Solve Microphone Fault 1. Check the Microphone settings. Figure Jumper Setting For Microphone 2. If all the settings are normal, then check and clean the Microphone tips and connector. If the problem is not solved then check the Microphone with the multimeter in Buzzer Mode. If the value is not in between that range, then change the Microphone.
Note that only one side will give a value. If the problem is not solved then check the track of the Microphone section. Do Jumper wherever required. If the problem is not solved then heat or change the Microphone IC. It is controlled by the CPU. Clean the display tips and display connector. Resold the display connector 3. Change the display 4. Check the display Track. Resold or change the display IC. Heat, reball or change the CPU. Change the track to solve the problem.
Figure 36 shows a diagram of series and parallel connections. Check the light settings. If the settings are normal then resold all the LED.
If the problem is not solved then change the display or the screen. Next check all the LEDs with the multimeter on Buzzer mode. If the LED is good then it will glow. If the LED is faulty then it will not glow.
Change the LED or jumper if required. If the problem is not solved then check the Track of the light section of the PCB and jumper if required. This subsystem includes two elements which are discussed below. This controller manages the resources of radio to control different items like handover in the collection of BTSs, assigns channels. It converses with the Base Transceiver Stations over Abis interface. The subsystem element in the base station of the GSM network uses the radio allowable technology to allow a number of operators to right to use the system concurrently.
Every channel supports up to 8 operators by allowing a base station to include different channels; a huge number of operators could be accommodated through every base station. These are located carefully through the provider of the network to allow whole area coverage. This area can be enclosed with a base station that is often being called a cell. Because it is not achievable to stop the signals from overlapping into the nearby cells and channels which are used in single-cell are not utilized in the next.
It is the mobile phone which consists of the transceiver, the display, and the processor and is controlled by a SIM card operating over the network. At present, their dimension has reduced radically whereas the functionality level has very much increased.
And one more benefit is that the time among charges has drastically enlarged. The mobile station includes a number called the IMEI. It is accessed by the network during registration to check whether the equipment has been reported as stolen. It should be noted down that when the number of BS enhances through the subscriber population scaling then some of the preservation tasks are moved to the base transceiver stations so that the ownership cost of the system can be reduced.
The GSM network architecture of 2G mainly follows a logical technique of operation. This is very simple as compared with present architectures of mobile phone network which utilize software-defined units to allow extremely supple operation. When the GSM system is digital, then the network is a data network. The security strategies standardized for the GSM system make it the most secure telecommunications standard currently accessible.
Although the confidentiality of a call and secrecy of the GSM subscriber is just ensured on the radio channel, this is a major step in achieving end-to-end security. A GSM modem is a device that can be either a mobile phone or a modem device that can be used to make a computer or any other processor communicate over a network.
It can be connected to a computer through serial, USB, or Bluetooth connection. The GSM modem has a wide range of applications in transaction terminals, supply chain management, security applications, weather stations, and GPRS mode remote data logging. These days, the GSM mobile terminal has become one of the items that are constantly with us. The requirement for a person to be reachable or to call anyone at any time is very appealing.
This project, as the name says the project is based on GSM network technology for transmission of SMS from sender to receiver. SMS sending and receiving is used for ubiquitous access to appliances and allowing breach control at home. The system proposes two sub-systems.
The appliance control subsystem enables the user to control home appliances remotely and the security alert subsystem gives automatic security monitoring. The second aspect is that of security alert which is achieved in a way that on the detection of intrusion, the system allows automatic generation of SMS thus alerting the user against security risk.
GSM technology will allow communication anywhere, anytime, and with anyone. The functional architecture of GSM employing intelligent networking principles, and its ideology, which provides the development of GSM is the first step towards a true personal communication system that enough standardization to ensure compatibility.
In both situations, the only way which can provide a solution is by using the mobile communication system. The doctor simply monitors the patient details and gives back the instructions to the person in the 1 st case so that he can at least take some precautions before finally reaching the hospital and in the 2 nd case monitors the test results of the patient and in case of any abnormalities, takes the next step for further treatment. If you liked it then please share it or if you want to ask anything then please hit comment button.
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