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danish_jalal
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PostSubject: Mobile Repairing Training   Wed Mar 30, 2011 12:49 am

Introduction To Mobile Phone Parts.

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 on top of the mother board
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danish_jalal
super Admin
super Admin


Male Number of posts: 800
Age: 32
Location: india (now in ksa)
Registration date: 2007-12-06

PostSubject: Re: Mobile Repairing Training   Wed Mar 30, 2011 12:53 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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danish_jalal
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Male Number of posts: 800
Age: 32
Location: india (now in ksa)
Registration date: 2007-12-06

PostSubject: Re: Mobile Repairing Training   Wed Mar 30, 2011 1:02 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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danish_jalal
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Male Number of posts: 800
Age: 32
Location: india (now in ksa)
Registration date: 2007-12-06

PostSubject: Re: Mobile Repairing Training   Wed Mar 30, 2011 1:03 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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asmeena
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Number of posts: 24
Age: 28
Registration date: 2011-05-06

PostSubject: Re: Mobile Repairing Training   Mon May 30, 2011 12:03 pm

This is very useful training. Thanks a lot for teaching.
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