MOBILE FOULT TRACING SECTION

First topic message reminder :

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.

Thank you very much,good job

what to do?

asalam o alequm sir g urdu main batayn kese repairing kaeain english mujhe samaj nahin aati plz sir ji im umair jamal my number is 03363050341

nice sir