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 MOBILE FOULT TRACING SECTION

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PostSubject: MOBILE FOULT TRACING SECTION   2/2/2008, 6:09 am

Dead Set Repairing
We are going to discuss here some techniques and steps to repair dead condition in mobile phones irrespectively of brands
First of all let us now about the main functions to power on a mobile phone you can consult our previous lesson

1.



Key Componentsand funtions:
Battery
Power Switch
battery terminal
Power IC
Oscilator
Frequency divider
CPU
Flash (ROM / EEPROM)
.
Battery:
A battery is used to provide power supply to our mother board unit so if this battery or on of its funtions fails the whole mobile phone fails to power on. So battery must be in good condition to make a mobile phone power on. Some times the third Pin used in battery which is called "BSI" is not working correctly but voltage can be found in " + " and " - " terminals, in this situation mobile phone cannot turn on.
Power Switch:
A power switch is used in a mobile phone to turn on and off mobile phones if it is faulty the whole unit cannot power on so keep checking its terminals wether they are connected with the power IC of not if not then you can make a jumpwer and connect it.
Battery terminal:
battery terminals connect battery to mobile phone component unit if its points are dry soldered of unsoldered or bended then you can change and fix this problem which is alwways in the result of no power on. so if battery terminals are working correctly you need to proceed further.
Power IC:
A power IC distributes current among all the components actually a power IC works as " voltage regulator" and " power on funtion" so if a power on funtion is faulty the whole unit will not power on. but there are some problems with ICs that we cannot check them wether they are working right or not rather we can only assume that they are faulty if the other functions are correct.
Oscilator:
An oscilator makes low frequency which is called clock frequency. this frequency is used to run digital components if this frequency is not available digital components fail to work and the result is power on failure. the out put frequency is used in mobile phone's CPU and Memory chips and UEM Ic if used.
Frequency divider:
Frequency dividing is a funtion which is used in mobile phones to divide clocke frequency to get accurate frequency to run digital components so if divider is failed power on fault mat occur. this frequency dividing funtion is built in radio ICs commonly like hagar IC or Mojoelner in Nokia mobile phones.
CPU
A CPU (central processing unit) is like a brain in mobile phones which controls the major parts of mobile phones so its funtionality is very necessory in mobile phones while testing in boot process but its functionality is assosiated with Memory chips used in mobile phone specially Flash chip.
Flash Chip ( EEPROM)
A flash chip holds booting information in it self it has instructions stored in itself for the CPU to control other components so if flash chip or its software is damaged it mean the set do not power on. in case of damaged software the phone should be treated in flashing process
* The word flashing denotes in mobile phones that some software installation.



Steps to Repair Dead Set

Note Some steps which cannot be take in an average mobile phone lab are avoided to be explained becaues oscilator and divider's functionality can be cehecked by Osciloscope which is not available in an common mobile phone lab.

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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 6:11 am

Charging Faults

charging faults are mainly of three types
No charging
Not charging
Auto charging
No charging:
in this fault a mobile phone does not charge at all when charging pin is inserted nothing happens it is always due to damaged fuse. or broken charging supply track if we repair fuse or jumper broken tracks we can set this fault off.
but on the first step I am telling you how to check no charging fault.
Check Your battery if it is not connected properly no charging fault occurs.
check continuity between charging pins it should be nor full nor high resistance.
if it is showing full continuity then there may be some problem in your charging IC may it is totally short you can re hot /replace this IC.
if there is no continuity in charging pins 90% fuse is damaged. you can replace fuse or jumper it. if a fuse shows full continuity in multi meter then it is working correctly if it is not so it is damaged.
if fuse is not damaged you can check tracks if broken.
if fuse, battery and tracks are ok then charging IC would be damaged.


Not charging:
in this fault a mobile phone shows a message "Not charging" on the screen when ever it is connected with charging pins. this type of fault is not a mere hardware fault it is 90% software fault. this fault is present only in nokia and I personally experienced a problem with a nokia 3100 it was showing "Not charging" i tried hardware solutions but totally in vain so I upgraded my software now every thing was ok. . and this is the same case in many types of nokia brands you can check this up.
Only nokia 1100 when "Not charging" fault comes it is very hard to remove this fault in nokia 1100 I only repaired a little number of nokia 1100 displaying this message there was a problem in charge connector diode next to charging fuse. but often it can be solved by repairing software or upgrading it.
Auto Charging:
In auto charging a phone continues showing charging despite of removing charging pin from phone.
in this type of fault the "BSI" pin of mobile phone is very important because it is used to tell the phone what is the state of mobile phone charging now so if this pin is not ok this fault occurs.
there are some cases in wich a mobile phone battery is ok but auto charging is present you can check transistors if used in charging section and if faulty replace it because this transistor is used in some mobilephones to cut off charging from phone automatically. in
In some cases a resistance in charging section is responsible for that which is marked as "R22" in charging section so you can check "+" supply connection with this

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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 6:12 am

Filters .antenna Switch .. What Are They?

Antenna Switches are used in Mobile Phones extensively at the very first stage of the point of entry of the signal (called the received signal Rx) into the mobile phone which also eventually becomes the point of exit for the outgoing signal or the transmitted signal Tx.

ANTENNA SWITCH .. FILTERS .WHAT ARE THEY?

ANTENNA SWITCHES OR DIPLEXERS ARE DEVICES WHICH transmit and receive on the same antenna at the same time, reject unwanted signals and feed two different signals to the same antenna.

(ANTENNA SWITCH IS ALSO KNOWN AS A DIPLEXER ! )

The common application for a diplexer is to connect a dual band mobile radio's two antenna connections to a common feed line and antenna. A diplexer is a simple high and low pass filter connected together. The filters are explained in detail below.

Diplexers are three-terminal frequency-dependent devices that can be used as a separator or a combiner of signals. It can have more than three terminals also. The device consists of two fixed tuned bandpass filters sharing a common port. The common port and the output of the two filters (RX and TX) form the three terminals of the diplexer. Signals applied to common port are separated in accordance with their passband frequencies of the filters. Signals applied to either uncommon port are isolated from the other uncommon port and are combined at the common port.

Picture of a DIPLEXER


If u can't find the PICTURE HERE, please download the attached file for viewing it.

As is common knowledge, a FILTER is a device which removes unwanted items from a mix and provides us with a finished product which is a pure final product of our requirement.

Electronic filters are electronic circuits which carry out the signal processing functions, specifically intended to enhance wanted signal components and/or remove unwanted ones.

SAW (surface acoustic wave) filters are electromechanical devices commonly used in radio frequency applications. Electrical signals are converted to a mechanical wave in a piezoelectric crystal; this wave is delayed as it propagates across the crystal, before being converted back to an electrical signal by further electrodes. The delayed outputs are recombined to produce a direct analog implementation of a finite impulse response filter. This hybrid filtering technique is also found in an analog sampled filter.

Passive filters :The simplest electronic linear filters are based on combinations of resistors, inductors and capacitors. These filters exist in so-called RC,LC,RL, and RLC varieties. All these types are collectively known as passive filters, because they do not depend upon an external power supply. Inductors block high-frequency signals and conduct low-frequency signals, while capacitors do the reverse. A filter in which the signal passes through an inductor, or in which a capacitor provides a path to earth, therefore presents less attenuation to low-frequency signals than high-frequency signals and is a low-pass filter. If the signal passes through a capacitor, or has a path to ground through an inductor, then the filter presents less attenuation to high-frequency signals than low-frequency signals and is a high-pass filter. Resistors on their own have no frequency-selective properties, but are added to inductors and capacitors to determine the time-constants of the circuit, and therefore the frequencies to which it responds.
At very high frequencies (above about 100 megahertz or megacycles.), sometimes the inductors consist of single loops or strips of sheet metal, and the capacitors consist of adjacent strips of metal. These are called stubs.
Active filters: Active filters are made up by using a combination of passive and active (amplifying) components. Amplifiers are frequently used in active filter designs. These can have high selectivity, and achieve the desired selectivity without the use of inductors. However, their upper frequency limit is limited by the bandwidth of the amplifiers used.
Generally, each family of filters can be assigned a particular order. The higher the order, the more the filter will approach the "perfect" filter of complete transmission in the pass band, and complete attenuation in the stop band.
Each family can be used to specify a particular pass band in which frequencies are transmitted, while frequencies outside the pass band are more or less attenuated.
Low-pass filter - Low frequencies are passed, high frequencies are attenuated.
High-pass filter - High frequencies are passed, Low frequencies are attenuated.
Band-pass filter- Only frequencies in a frequency band are passed.
Band-stop filter - Only frequencies in a frequency band are attenuated.
All-pass filter - All frequencies are passed, but the phase of the output is modified.
An analogue filter handles analogue signals or continuous-time signals, whether electric potential, sound waves, or mechanical motion directly. This is opposed to a digital filter that operates on discrete-time signals. Older analog filters (newer filters are digital filters) work entirely in the analog realm and must rely on physical networks of electronic components (such as resistors, capacitors, transistors, etc.) to achieve a desired filtering effect.
Passive filter: A passive component is an electronic component that does not require a source of energy to perform its intended function. Examples of passive components include resistors, capacitors, and inductors.
A passive filter is an electronic filter made entirely from passive components.
Active filter: An Active filter is the one which involves active component that make use of a semi-conductor device like a transistor, an electronic device that requires a source of energy to perform its intended function.
A active component is one that can be used to provide gain or an amolification of the signal in an electronic circuit. It contains mainly semiconductor devices like diodes and transistors.

Digital filter : A digital filter is any electronic filter that works by performing digital math operations on an intermediate form of a signal.
Digital filters can easily achieve performance metrics far beyond what is (even theoretically) possible with analog filters. It is not particularly difficult, for example, to create a 1000Hz low-pass filter which can achieve near-perfect transmission of a 999Hz input while entirely blocking a 1001Hz signal. Analog filters cannot split apart such closely spaced signals.
Also, for complex multi-stage filtering operations, digital filters have the potential to attain much better signal to noise ratios (more of desired signal in comparision to unwanted signals) than analog filters. This is because whereas at each intermediate stage the analog filter adds more noise to the signal, the digital filter performs noiseless math operations at each intermediate step in the transform. The primary source of noise in a digital filter is found in the initial analog to digital conversion step, where in addition to any circuit noise introduced, the signal is subject to an unavoidable selectivity error due to the finite resolution of the digital representation of the signal.
Digital filters can achieve virtually any filtering effect that can be expressed as a mathematical algorithm. The two primary limitations of digital filters are their speed (the filter can't operate any faster than the computer at the heart of the filter), and their cost. However as the cost of integrated circuits have continued to drop over time, digital filters have become increasingly commonplace and are now an essential element of many everyday objects such as radios, cellphones, and stereo receivers. Digital filters can easily achieve performance levels far more than what is (even theoretically) possible with analog filters. It is not particularly difficult, for example, to create a 1KHz low-pass filter which can achieve near-perfect transmission of a 0.999KHz input while entirely blocking a 1.001KHz signal. Analog filters cannot split apart such closely spaced signals.
Mobile Phones make use of Filters called Dual Band-pass filters because they need to allow two frequencies of signals most commonly 900MHz and 1800MHz in the dual band mobile phones. Also Antenna Switches are used in Mobile Phones expensively at the very first stage of the point of entry of the signal (called the received signal Rx) into the mobile phone which also eventually becomes the point of exit for the outgoing signal or the transmitted signal Tx. The newer models of the Mobile Phones like a Nokia 6600 makes use of an active Antenna Switch which also has a built-in amplifier circuit inside it to immediately boost the Rx signal.

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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 6:15 am

Common Faults In Mobile Phones


A typical mobile phone has various types of faults which can be distributed in two main kinds of faults
Hardware faults
Software faults
Setting Faults
Hardware Faults:
Hardware faults in mobile phones are related to mother boards of mobile phone, batteries and any physical fault will be amount to hardware faults. I have pointed out as much hardware faults as much i remeber this time but if you have a fault which is not listed below you can tell me by clicking here I willo be glad to know that it would be a great help for me too.The list of common hardwarefaults is given below.
dead set condition
no charging
battery empty
auto charging
low signal
No signal
voice problem
vibrator problem
ringer problem
backlight problem
auto turn off
hanging problem
insert sim (no sim card inserted shows on the screen)
keypad problem
display problem
Software problems:
hanging problem
no signal
dead set
display
contact service (contact retailer, contact service provider)
Test mode
not charging
Setting problem:
call divert
sim lock
security code
country lock
cnfiguration of SMS
configuration of GPRS
configuration of call

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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 6:16 am

..:: RX and TX Service Network Problems ::..

there is two
sections in network 1, Rx section. 2, Tx section. all technicians need
to use manual searching in mobile phone, testing for Rx section and Tx
section.

HOW TO FIND WHICH SECTION IS FAULT Tx (or) Rx?


Testing Rx section

use manual [You must be registered and logged in to see this image.]
for Testing Rx section, after searching Rx section good condition means
it shows network list like Airtel, hutch, (or) any other network list
in your area,


If Rx section bad condition after searching it shows NO NETWORK FOUND

1, after searching it shows network list means Rx section is ok.
2, after searching it shows NO NETWORK FOUND or some networks missing means Rx section is faulty.

Testing Tx section

Use manual [You must be registered and logged in to see this image.]
for testing Tx section, after searching it shows network list, then you
can choose your simcard network, if Tx section is good condition it
shows HOME NETWORK SELECTED, if Tx section is fault it shows NO ACCESS.


1, after selecting network it shows HOME NETWORK SELECTED means Tx section is ok.
2, after selected network it shows NO ACCESS means Tx section is fault.


Information of Rx section components and ics nokia dct-3 tech

1, antenna switch

2, RF IC ( Hagar ic )

3, AUDIO IC ( cobba ic)

4, crystal oscillator

5, filters

6, VCO (voltage control oscillator



Information of Tx section components and ics nokia dct-3 tech

1, PF IC (PA IC)


Information of Rx section components and ics nokia dct-4 tech

1, antenna switch

2, filters

3, RF IC

4, crystal oscillator

5, VCO (voltage control oscillator)

6, UEM IC


Information of Tx section components and ics nokia dct-4 tech


1, PF IC (PA IC)


HOW TO SERVICE Rx SECTION FAULT ?

Solution for Rx section no network found fault nokia dct-3 technolagy

1,clean the pcb well and Rehot (if not ok follow one by one solutions)

1, give antenna switch jumper

2, Rehot the RF IC

3, Rehot the AUDIO IC

4, Reball the RF IC

5, change the RF IC

6, change the AUDIO IC

7, change the crystal oscillator


Solution for Rx section NO NETWORK FOUND fault nokia dct-4 technology

1, clean the pcb well and Rehot (if not ok follow one by one solutions)

2, give antenna switch jumper

3, Reheat the RF IC

4, change the crystal oscillator

5, Reball the RF IC

6, change the RF IC

7, Change filters


HOW TO SERVICE Tx SECTION FAULT ?


Solution for Tx section NO ACCESS fault nokia dct-3 technolagy

1, Change the PF IC


Solution for Tx section NO ACCESS fault nokia dct-4 technolagy


1, Change the PF IC


SOLUTION FOR OTHER NETWORK FUALT


Solution for low network coverage, all models


1, give jumper from antenna contact to cabinet antenna

2, change the antenna switch


Solution for dct-3 technology
When switch on the mobile it shows full network after few seconds its goas down


1, flash - Rebuild ime - UI settings (if not ok follow 2nd solution)

2, check the track from battery +ve point to PA IC, if track is ok then change the good PF IC.



Solution for dct-4 technology
When switch on the mobile it shows full network after few seconds its goas down


1, write good pm file (if not ok follow 2nd solution)

2, change the PF IC, if still the problem same check the PF power track to battery +ve point

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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 6:17 am

Mobile Phone Functions


There are three major sections inside a mobile phone
Power Section
Radio Section
Computer Section
Power Section:
A power section deals with power related tasks such as power distribution or charging the battery so this section can be divided into two sub sections like.
Power Distribution
A power distribution section is built around an "power IC" it takes 3.6V power from battery and regulates its power and then distributes to the other components used in mobile phone circuit. in some mobile phones tech "RF Power amplifier" uses more Power than provided bye mobile phone's battery .i.e. 4.7 V or 5.6 V in some phones. the power Ic with a power boaster coil is used to increase voltages. so we can say that power IC is used to provide power to other components how much they needed. either less than battery voltage or more than it.
Charging Section
A charging section works for battery charging purposes.it is often consists a fuse, a coil, a protecting diode, a filter capacitor and charging IC and some other discreet. the charging section helps battery to be charged when it needs and when battery is charged, charging IC reads its state of charge and feels it full charged and then disconnects charging from it.
Radio Section:
A radio section has basically a set of four main functions.wich are.
Band Switching
RF Power Amplification
Transmitter
Receiver
Band Switching:
In the modern mobile phone communication techniques. the frequency of mobile phone communication is divided into three bands
GSM (operates on 900 MHz)
DCS (operates on 1800 MHz)
PCS (operates on 1900 MHz)
the third band is used only in USA whereas the first two bands are used in the rest of the world. band switching is done bye a "ceramic antenna switch" it reads from the radiation dispersed in the air and then switches to the appropriate band.
in the very first phase of mobile phones there were single band handsets which operated on single frequency band but now a days all the handsets are dual band or tri band in operation.
RF Power Amplifier
RF power amplifier is often called as ".PA" or"Transmitter" its functions is to amplify or boast the power which is being transmitted to air, so may it would be able to communicate with long distances. a typical .PA can amplify rf power up to 0.6W or 600mW. This amount of rf power is sufficient to communicate nearly 20 to 25 kilometers in open area, but all the PA's are controlled by there rf signal processor, so if we are near our cell base tower the PA of our phone will transmit low power but if we are far away it will produce its maximum power.
Transmitting
A mobile phone's rf section is basically built around an rf IC which is often called rf signal processor whereas in nokia it is called hagar IC in some hand sets and in some hand sets it is called Mjoelner. irrespectively of the brands and verity of names we call it rf signal processor. this IC works as transmitter and receiver as well. working as transmitter it takes instructions from phone's computer and also takes audio data from audio section and creates radio waves then mixes audio data to its radio waves according to the instructions given by computer section. this mixer of audio and radio is sent to PA to amplify its strength
Reciever
A reciver section for rf waves is built in rf IC, as it is said that this IC works for dual purposes first transmitting and section recieving. in the recieving section of mobile phones a radio signal is gather from ceramic antenna switch and then it is filtered and sent to rf IC to further process. in rf IC signal is detected and then rectified for audio and data which is sent to audio IC or computer section.
Computer Section:
A computer section in mobile phone consists of two main functions
CPU(central processing unit)
Memory (RAM, FLASH, COMBO CHIP)
CPU:
A CPU is used in mobile phones as a central processing arithematic or controler. the cpu controls various functions in mobile phones like signal, display, sound converting(DSP), charging, power on, rf channel controler, rf tx power conroller, LEDs, vibrator, data processing, data storing etc. so we can say that if a cpu is damaged in any mobile phone it cannot be repaired unless the CPU is not replaced but this type of fault is not even seen to me ever either memory chips can be damaged. in brand Nokia CPU is named with two different words (MAD or UPP)
Memory:
there are two main types of memories used in mobile phones
RAM (Random Access Memory)
The RAM is used in mobile phones to store user data in mobile phones. So these a days we can store pictures, messages, ringtones, applications, themes and other these type of things in mobile phones so CPU stores these types of data in the RAM of our mobile phones.
Flash (eeprom, ROM etc)
The flash chip is used in mobile phones to hold mobile phone's operating system in it. so if the flash chip is damaged in mobile phones the phone cannot power on properly because all the instructions to start a mobile phones and its various tasks like call making , display etc are stored in the flash chip of mobile phones.
Combo Chip
In smoe mobile phones there is a combined type of memory used which is called combo memory chips these types of memories work for both like RAM and Flash.The clear example of this type of memory is used in Nokia 1100.
Note: Multy Media Cards are not a part of mobile phones becaues they are used externally.

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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 6:19 am

Introduction to Mobile Phone Part II




Dear friends here we will discuss about what kind of functions a typical mobile phone has so let us start our new lesson. while starting i would like to say all of you that you please keep in touch with me by our contact us page and please don't feel any hesitation to ask me any question if you have about these lessons. these lessons will make you learn good repairing skills so keep reading these lectures.
First of all we will discuss how many main functions a mobile phone often has irrespectively of mobile brands.
There are three major sections inside a mobile phone

Power Section
Radio Section
Computer Section
Power Section:
A power section deals with power related tasks such as power distribution or charging the battery so this section can be divided into two sub sections like.
Power Distribution
A power distribution section is built around an "power IC" it takes 3.6V power from battery and regulates its power and then distributes to the other components used in mobile phone circuit. in some mobile phones tech "RF Power amplifier" uses more Power than provided bye mobile phone's battery .i.e. 4.7 V or 5.6 V in some phones. the power Ic with a power boaster coil is used to increase voltages. so we can say that power IC is used to provide power to other components how much they needed. either less than battery voltage or more than it.
Charging Section
A charging section works for battery charging purposes.it is often consists a fuse, a coil, a protecting diode, a filter capacitor and charging IC and some other discreet. the charging section helps battery to be charged when it needs and when battery is charged, charging IC reads its state of charge and feels it full charged and then disconnects charging from it.
Radio Section:
A radio section has basically a set of four main functions.wich are.
Band Switching
RF Power Amplification
Transmitter
Receiver
Band Switching:
In the modern mobile phone communication techniques. the frequency of mobile phone communication is divided into three bands
GSM (operates on 900 MHz)
DCS (operates on 1800 MHz)
PCS (operates on 1900 MHz)
the third band is used only in USA whereas the first two bands are used in the rest of the world. band switching is done bye a "ceramic antenna switch" it reads from the radiation dispersed in the air and then switches to the appropriate band.
in the very first phase of mobile phones there were single band handsets which operated on single frequency band but now a days all the handsets are dual band or tri band in operation.
RF Power Amplifier
RF power amplifier is often called as ".PA" or"Transmitter" its functions is to amplify or boast the power which is being transmitted to air, so may it would be able to communicate with long distances. a typical .PA can amplify rf power up to 0.6W or 600mW. This amount of rf power is sufficient to communicate nearly 20 to 25 kilometers in open area, but all the PA's are controlled by there rf signal processor, so if we are near our cell base tower the PA of our phone will transmit low power but if we are far away it will produce its maximum power.
Transmitting
A mobile phone's rf section is basically built around an rf IC which is often called rf signal processor whereas in nokia it is called hagar IC in some hand sets and in some hand sets it is called Mjoelner. irrespectively of the brands and verity of names we call it rf signal processor. this IC works as transmitter and receiver as well. working as transmitter it takes instructions from phone's computer and also takes audio data from audio section and creates radio waves then mixes audio data to its radio waves according to the instructions given by computer section. this mixer of audio and radio is sent to PA to amplify its strength
Reciever
A reciver section for rf waves is built in rf IC, as it is said that this IC works for dual purposes first transmitting and section recieving. in the recieving section of mobile phones a radio signal is gather from ceramic antenna switch and then it is filtered and sent to rf IC to further process. in rf IC signal is detected and then rectified for audio and data which is sent to audio IC or computer section.
Computer Section:
A computer section in mobile phone consists of two main functions
CPU(central processing unit)
Memory (RAM, FLASH, COMBO CHIP)
CPU:
A CPU is used in mobile phones as a central processing arithematic or controler. the cpu controls various functions in mobile phones like signal, display, sound converting(DSP), charging, power on, rf channel controler, rf tx power conroller, LEDs, vibrator, data processing, data storing etc. so we can say that if a cpu is damaged in any mobile phone it cannot be repaired unless the CPU is not replaced but this type of fault is not even seen to me ever either memory chips can be damaged. in brand Nokia CPU is named with two different words (MAD or UPP)
Memory:
there are two main types of memories used in mobile phones
RAM (Random Access Memory)
The RAM is used in mobile phones to store user data in mobile phones. So these a days we can store pictures, messages, ringtones, applications, themes and other these type of things in mobile phones so CPU stores these types of data in the RAM of our mobile phones.
Flash (eeprom, ROM etc)
The flash chip is used in mobile phones to hold mobile phone's operating system in it. so if the flash chip is damaged in mobile phones the phone cannot power on properly because all the instructions to start a mobile phones and its various tasks like call making , display etc are stored in the flash chip of mobile phones.
Combo Chip
In smoe mobile phones there is a combined type of memory used which is called combo memory chips these types of memories work for both like RAM and Flash.The clear example of this type of memory is used in Nokia 1100.
Note: Multy Media Cards are not a part of mobile phones becaues they are used externally.

Mobile Phone Function


Dear friends here we will discuss about what kind of functions a typical mobile phone has so let us start our new lesson. while starting i would like to say all of you that you please keep in touch with me by our contact us page and please don't feel any hesitation to ask me any question if you have about these lessons. these lessons will make you learn good repairing skills so keep reading these lectures.

First of all we will discuss how many main functions a mobile phone often has irrespectively of mobile brands.
There are three major sections inside a mobile phone


Power Section
Radio Section
Computer Section
Power Section:
A power section deals with power related tasks such as power distribution or charging the battery so this section can be divided into two sub sections like.
Power Distribution
A power distribution section is built around an "power IC" it takes 3.6V power from battery and regulates its power and then distributes to the other components used in mobile phone circuit. in some mobile phones tech "RF Power amplifier" uses more Power than provided bye mobile phone's battery .i.e. 4.7 V or 5.6 V in some phones. the power Ic with a power boaster coil is used to increase voltages. so we can say that power IC is used to provide power to other components how much they needed. either less than battery voltage or more than it.
Charging Section
A charging section works for battery charging purposes.it is often consists a fuse, a coil, a protecting diode, a filter capacitor and charging IC and some other discreet. the charging section helps battery to be charged when it needs and when battery is charged, charging IC reads its state of charge and feels it full charged and then disconnects charging from it.

Radio Section:
A radio section has basically a set of four main functions.wich are.
Band Switching
RF Power Amplification
Transmitter
Receiver
Band Switching:
In the modern mobile phone communication techniques. the frequency of mobile phone communication is divided into three bands
GSM (operates on 900 MHz)
DCS (operates on 1800 MHz)
PCS (operates on 1900 MHz)
the third band is used only in USA whereas the first two bands are used in the rest of the world. band switching is done bye a "ceramic antenna switch" it reads from the radiation dispersed in the air and then switches to the appropriate band.
in the very first phase of mobile phones there were single band handsets which operated on single frequency band but now a days all the handsets are dual band or tri band in operation.
RF Power Amplifier
RF power amplifier is often called as ".PA" or"Transmitter" its functions is to amplify or boast the power which is being transmitted to air, so may it would be able to communicate with long distances. a typical .PA can amplify rf power up to 0.6W or 600mW. This amount of rf power is sufficient to communicate nearly 20 to 25 kilometers in open area, but all the PA's are controlled by there rf signal processor, so if we are near our cell base tower the PA of our phone will transmit low power but if we are far away it will produce its maximum power.
Transmitting
A mobile phone's rf section is basically built around an rf IC which is often called rf signal processor whereas in nokia it is called hagar IC in some hand sets and in some hand sets it is called Mjoelner. irrespectively of the brands and verity of names we call it rf signal processor. this IC works as transmitter and receiver as well. working as transmitter it takes instructions from phone's computer and also takes audio data from audio section and creates radio waves then mixes audio data to its radio waves according to the instructions given by computer section. this mixer of audio and radio is sent to PA to amplify its strength
Reciever
A reciver section for rf waves is built in rf IC, as it is said that this IC works for dual purposes first transmitting and section recieving. in the recieving section of mobile phones a radio signal is gather from ceramic antenna switch and then it is filtered and sent to rf IC to further process. in rf IC signal is detected and then rectified for audio and data which is sent to audio IC or computer section.
Computer Section:
A computer section in mobile phone consists of two main functions
CPU(central processing unit)
Memory (RAM, FLASH, COMBO CHIP)
CPU:
A CPU is used in mobile phones as a central processing arithematic or controler. the cpu controls various functions in mobile phones like signal, display, sound converting(DSP), charging, power on, rf channel controler, rf tx power conroller, LEDs, vibrator, data processing, data storing etc. so we can say that if a cpu is damaged in any mobile phone it cannot be repaired unless the CPU is not replaced but this type of fault is not even seen to me ever either memory chips can be damaged. in brand Nokia CPU is named with two different words (MAD or UPP)
Memory:
there are two main types of memories used in mobile phones
RAM (Random Access Memory)
The RAM is used in mobile phones to store user data in mobile phones. So these a days we can store pictures, messages, ringtones, applications, themes and other these type of things in mobile phones so CPU stores these types of data in the RAM of our mobile phones.
Flash (eeprom, ROM etc)
The flash chip is used in mobile phones to hold mobile phone's operating system in it. so if the flash chip is damaged in mobile phones the phone cannot power on properly because all the instructions to start a mobile phones and its various tasks like call making , display etc are stored in the flash chip of mobile phones.
Combo Chip
In smoe mobile phones there is a combined type of memory used which is called combo memory chips these types of memories work for both like RAM and Flash.The clear example of this type of memory is used in Nokia 1100.
Note: Multy Media Cards are not a part of mobile phones because they are used externally.


Mother Board System

This Lesson is intended to make you aware of the Fundamentals of a mobile phone's mother board and I want to teach you about what a typical mother board.

A typical mother board is constructed using two main things
Fiber Plate
Copper Plate
These two plates are joined in three forms.
Single layer board
Double layer board
Three or tripple layer board
A single layer board is constructed yusing one copper plate and the other fiber plate. Its one side is copper faced and other is fiber faced.
while a Double layer board is made with two copper sheets ad fiber sheet.Its one side is copper faced and the other is also copper faced and the fiber is stcked between two copper sheets.this kind of board holds electronic components on both of its side because both copper sided prints anre inter connected with one another on proper places
A three layer board is made with three copper sheets and two fiber sheet.as it is shown below.
Basics about Mother Boards
Different mother boards have different views but many things are common in different brand mother boards.first common thing is ,every mother board has radio Section(Discussed in Lesson 1) on top of the mother board

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waqas ahmed
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 6:49 am

verry important to sharing sir

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waqas mmz
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 7:19 am

i am new in mobiles repearing

but i am not new reading this thread
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 8:23 am

good
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/2/2008, 4:12 pm

thats good share .
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/3/2008, 5:51 am

nice sharing, that is very necessary for the new guys,

thanks, keep it more up
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RANA RASHEED
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/3/2008, 6:54 am

wow its great job
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/5/2008, 12:42 am

Good share sir, very helpfull
Thank's advace
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/5/2008, 2:02 pm

thanks for nice information
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/6/2008, 11:42 am

thats good share
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/20/2008, 5:46 am

Plzzz Urdu Main Likhain To Kafi Aasani Hogi Samjhnay Main
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PostSubject: Re: MOBILE FOULT TRACING SECTION   2/20/2008, 7:30 am


ا
اردو ميں بھي ھے اسي سيکشن کو چيک کرو

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PostSubject: Re: MOBILE FOULT TRACING SECTION   3/20/2008, 1:35 am

thanks brother he is very improtant for begner
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PostSubject: Re: MOBILE FOULT TRACING SECTION   4/25/2008, 9:51 am

most welcome u dear

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PostSubject: Re: MOBILE FOULT TRACING SECTION   5/5/2008, 9:45 am

thanx
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PostSubject: Re: MOBILE FOULT TRACING SECTION   5/8/2008, 2:24 am

welllcome
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PostSubject: Re: MOBILE FOULT TRACING SECTION   5/17/2008, 10:01 pm

That's greatest information that's give us good lessons
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PostSubject: Re: MOBILE FOULT TRACING SECTION   8/19/2008, 4:54 am

thanx my dear
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PostSubject: Re: MOBILE FOULT TRACING SECTION   9/3/2008, 1:38 am

tell me about help
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