Smartphone Troubleshooting & Repair

352 Pages·2014·12.05 MB·English

by  Mr Victor Emeka

All Rights Reserved
All material in this book is copyrighted and may not be reproduced or
transmitted in any form or by any means, electronic or mechanical,
including photocopying, recording or by any information storage and
retrieval system, without permission in writing from the publisher.
Introduction
Before You Start
As a technician, you must understand a basic rule of business, time is money.
Whether you are boss or work for someone else, the ability to identify and
isolate a fault quickly and decisively is very important to the success of your
business. It requires some common sense, and a little bit of focus. It also requires
an understanding of the troubleshooting process, and reliable plan of action.
Even though the number of configuration and setups are virtually unlimited, the
methodology used to approach each repair is always about the same. This
introduction is intended to isolate the concepts of basic troubleshooting and
show you how to apply basic repair steps that will help you narrow the problem
down before you even take a screwdriver to the mobile phone. By applying a
constant technique. You can safe precious time from every repair.
The General Troubleshooting Steps
Regardless of how your particular smartphone might be, a dependable
Troubleshooting steps can be broken down into four basic steps.
#1:Define your symptoms,
#2: identify and isolate the location of your problem
#3: replace the suspected component, and
#4:re-test the component thoroughly to be sure that you have solve the
problem. If you have not solved the problem, start again from step #1:Thisis a
“universal” procedure that you can apply to any sort of troubleshooting __not
just for phones.
DEFINE YOUR SYMPTOMS
When a phones breaks down, the cause might be a simple as a loose wire or a
connector, or as complicated as an IC or component failure. Before you start,
you must have a good understanding of all the symptoms. Think about the
symptoms carefully. By recognizing and understanding your symptoms, it can be
much easier to trace a problem to the appropriate component. Take the time to
write down as many symptoms as you can. As a technician, you must often write
problems and solutions for reference purposes.
IDENTIFY AND ISOLATE
Before you try to isolate a problem within a piece of hardware, you must first be
sure that the equipment itself is causing the problem. In many cases, this will be
fairly obvious, but some situation might not be. A faulty or improperly
configured piece of software can cause confusing system errors. When you are
sure that it is a system’s hardware failure, you can begin to identify which
component fails.
REPLACE
Because phones are designed as a sub-unit, it is almost always easier to replace a
sub-unit outright, rather than attempt to repair the sub-unit to its component
level. Even if you had the time, to isolate defective component, many parts are
not inter-changeable, so it is better to replace the defective part than try to repair
it
RE-TEST
When a repair is finally complete, the system must be reassembly carefully
before testing it. All guards, housings, cables and shields must replaced before
final testing. If symptoms persist, you will have to reevaluate the symptoms and
narrow the problem to another parts of the equipment. If normal operation is
restored (or greatly improved), test the phones’s various function. When you can
verify that the symptoms have stop during actual operation, the equipment can
be returned to service. As a general rule, it is wise to let the system run for at
least 24 hours to ensure that the replacement sub-assembly will not fail
prematurely.
Do not be discouraged if the equipment still malfunctions. Maybe software
settings and device drivers may need to be updated to. If you are tired simply
walk away, clear your hand, and start again by defining the current symptoms.
Never continue with a repair if you are tired or frustrated tomorrow is another
day. Even the most experienced troubleshooters get overwhelmed from time to
time.
Contents
LESSON 01
Basic Information How Cellphone Works
Learning with Block Diagram on How basically Cellphone works
LESSON 02
Introduction To Basic Electronics
Ohm's Law
Series Circuit
Parallel Circuit
Identifying Electronics Components and Circuit Symbols Resistors
Capacitors
Transistors
Diodes
Fuse
Coils & Inductors
Crystal Oscillators
RF & IF Amplifiers and Filters
EMI and ESD Filters
LESSON 03
Preparing the Proper Tools For Repairing Opening Tools and Tweezers
Soldering and Desoldering Tools
Muti Tester
SMD Rework Stations
DC Power Supply
Cleaning Kits
Reballing Kits
Working Table Equipment
LESSON 04
Safety Procedures and Proper Handling of Tools and Test Equipment on
Cellphone Repair
How To Use and Read a Multimeter Tester
Test and Check up Procedures on Basic Electronics Components
Test and Check up Procedures on Basic Electronics Components
LESSON 05
Introduction to
Reading Cellphone's Schematic Diagrams
Identifying Component Symbols and Layout in Schematic Diagram
How to Identify Resistor's Symbols and Layout
How to Identify Capacitor's Symbols and Layout
How to Identify Transistor's Symbols and Layout
How to Identify Diodes Symbols and Layout
How to Identify Coil Symbols and Layout
How to Identify Integrated Circuit Symbols and Layout
How to Identify DC to DC Voltage Drivers, Regulators and
Converters Symbols and Layout
How to Identify EMI-ESD Symbols and Layout
How to Identify RF Filter Symbols and Layout
How to Identify Battery Cell Symbols and Layout
How to Identify Power Switch , Mouthpiece, Earpiece and Ringtones Speakers
User Interface Symbols and Layout
How to Identify Clock Crystal Oscillator Symbols and Layout
How to Identify Fuse Symbol and Layout
How to Identify the Lines and Symbols on Schematic Diagram
LESSON 06
How to Find and Locate Components on PC BoardHow to Solder SMD
Components Manually by Hand
How to Reball BGA Chips Manually by Hand
Identifying and Familiarization of Common Mobile Phones Components and
Spare Parts
Liquid Crystal Display LCD's Touch Screen Panels Microphones Micro
Speakers Switches Charging Pins Antenna's Batteries Battery Connectors USB
connectors Understanding Major Integrated Circuits (IC) on Mobile Phones
Power Management IC
Application Processor
Flash IC
RAM IC
Basic Hardware Handling Procedures
Proper Disassembling and Assembling Methods How to Test Mobile phone
Speaker, Buzzer or Ringer How to Test Mobile phone Microphone or
Mouthpiece How to test Mobile Phone Charger Voltage How to Test Mobile
Phone Vibra Motor How to check Mobile Phone Battery Voltage How to test
Power ON OFF Switch
Troubleshooting
How to Troubleshoot Not Charging Issues How charging circuit works
No Charging Response
Charger Not Supported
Not Charging
How SIM Circuits works
Insert Sim Card Problem
Invalid Sim Card
How Keypad Circuits Works
How to Map and Trace keypads Lines Understanding The LED light Circuits
Explanation on How Audio Circuits work Mouthpiece
Earpiece
Buzzer
Ringer
Headset
Vibra motor
How LCD Display Circuit Works
Understanding How RF circuit works
Basic Mobile Phones Hardware Repair Techniques
Basic on Software Handling What is Flashing
What is Unlocking
PART 1
Introduction:
How Cellphone Works
As a basic Part of a Technician, It is fully advice that he/she must have a basic
knowledge of what technology he or she come up to..
Before we proceed further, please take a simple brief to enhanced your
knowledge about the Field of What we are going to discuss hereafter.... Now
first come first we all ever wonder how does the cellphone works?
have you ever wondered how a cell phone works? What makes it different from
a regular phone? what's inside of it and how do they created it? What do all those
terms like PCS, GSM, CDMA and TDMA mean?
To start with, one of the most interesting things about a cell phone is that it is
actually a radio -- an extremely sophisticated radio, but a radio nonetheless. The
telephone was invented by Alexander Graham Bell in 1876, and wireless
communication can trace its roots to the invention of the radio by Nikolai Tesla
in the 1880s (formally presented in 1894 by a young Italian named Guglielmo
Marconi). It was only natural that these two great technologies would eventually
be combined.
If you prepare to take a deep knowledge, i recommended you to visit this site
and have a brief Fundamentals of Wireless Communication
A basic technician all need is just to have a simple understanding about
cellphones, we do not need extreme and intimate deeper meaning about it,
that's because what we are going to take around here is to fix what those various
mobile phones
company created and build....to make it as simple as that...
Cell Phone Network Technologies:
2G Technology
There are three common technologies used by 2G cell-phone networks for
transmitting information:
* Frequency division multiple access (FDMA)
* Time division multiple access (TDMA)
* Code division multiple access (CDMA)
Although these technologies sound very intimidating, you can get a good sense
of how they work just by breaking down the title of each one.
The first word tells you what the access method is. The second word, division,
lets you know that it splits calls based on that access method.
* FDMA puts each call on a separate frequency.
TDMA assigns each call a certain portion of time on a designated frequency.
CDMA gives a unique code to each call and spreads it over the available
frequencies.
The last part of each name is multiple access. This simply means that more than
one user can utilize each cell.