Cellular Phone Technician

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CELLULAR PHONE TECHNICIAN

Topic outline

1 What is a Cellular Phone Technicianfile

2 Working Environmentfile

3 Opportunities

Session Objectives

At the end of this session, you will be able to:

Know what is a Cellular Phone Technician

Learn the duties and responsibilities as a Cellular Phone Technician

Introduction

In this session, you will learn: What is a Cellular Phone Technician? What are the duties and responsibilities of a

Cellular Phone Technician?
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What is a Cellular Phone Technician?

A cellular phone technician carries out proper diagnosis and repair of damaged cellular phones.

As a cellular phone technician, it is important that you should also learn how to identify and know exactly the things youare going to undertake before performing troubleshooting of faulty cellular phones.

Duties and Responsibilities

Being a cellular phone technician entails duties and responsibilities which are as follows:

Prepare the work station

A cellular phone technician must work in a well-lighted work station. This is because of the small parts inside the cellular

phones interior. Most of the repairs are done with the use of electricity; make sure that the work station has sufficient access to

power outlets. All the tools and materials should be made available all the time.

Perform diagnostics, troubleshooting and repair of cellular phones

The main duty of a cellular phone technician is to repair faulty phones brought in by customers. He diagnoses andrepairs the phones, and informs the customers of when the phones will be available for pick-up.

Inform the customers about the warranties and after-sales service

It is the duty of the cellular phone technician to inform the customer about warranty issue if not serviced by an

accredited service center of the cellular phone manufacturer.


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Quality assurance

Before releasing the repaired cellular phone to the customer, make sure that all the functionalities of the phone areworking.

Session ObjectivesAt the end of this session, you will be able to:

Learn and identify the tools and materials that you will be needing in your work station

Know your clients and their needs.

Introduction

In this session, you will learn and understand your working environment and the things that you should be familiar with.

You will also know who your future clients for this job are

Your work station

Your work station will be your comfortable area or office where the diagnostic, troubleshooting and repair of cellular

phones take place. Your workstation should be completely equipped with tools and equipment.

TOOLS:

1. Screw Driver/star bit


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2. High grade magnifying glass with lamp

3. Cleaning brush (non static)

4. Soldering lead

5. Eraser stick for Cellular Phone

6. Cleaning agent7. Jumper wires

8. Silicon grease

9. Maintenance Board for reworks

10. BGA Plate with magnetic handle

11. Solder balls

EQUIPMENT:

1. Hot Air with soldering station

2. Power Supply

Other tools, equipment and supplies and materials

1. Tweezer

2. Multi-tester

3. Stabilized power unit

4. Oscilloscope

5. Digital Multi-meter

6. Soldering Iron

7. Solder Pump8. De-soldering wire

9. Needle Pliers

10. Wire Cutter (Nipper)

Previous Topic:

Session Objectives
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Next Topic:

Your Clients

Your work station

Your Clients

United Nations Reported that around 30% of the entire population is living on less than 1$ a day.

In the Philippines, most of the Filipinos don't have that much income to buy new cellular phones when they break.

Your clients are those individuals who bring their faulty cellular phones and need repair service.
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Session Objectives


Know and appreciate the opportunities as a cellular phone technician in the industry. Determine your clients and their needs.

Introduction

In this session, you will learn the possible opportunities in business and employment as a cellular phone repair

technician.

Business Opportunities

There is a growing demand for cellular phone repair jobs. Since there are already millions of people using cellular

phones in the Philippines, there is an increasing number of opportunities in the repair industry for people who have a good

understanding and know-how on cellular phone repair.

And learning cellular phone repair can result in career business opportunities by starting your own stand-alone cellular

phone repair shop.

Employment Opportunities

The cellular industry is one of the fastest-growing industries in the world and in the Philippines. The repair industry grew

dramatically over the past few years. This makes the demand for a cellular phone technician increase.



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Learn and understand what a cellular phone is.

Learn how do cell sites work for cellular phones

Know how a cellular phone transmits

Know the components of cellular phone

Module 2

How the Cellular Phone Works?

Introduction

In this session, you will be able to learn and understand what a cellular phone is, its components and how it works.

What is a cellular phone?

Cellular telephone, often called mobile telephone, is a type of short-wave analog or digital telecommunication in

which a subscriber has a wireless connection from a mobile telephone to a relatively nearby transmitter. It makes and

receives telephone calls over a radio link moving around a wide geographic area. The span of the transmitter of coverage

is called a cell. Generally, cellular telephone service is available in urban areas and along major highways. As the cellular

telephone user moves from one cell or area of coverage to another, the telephone is effectively passed on to the local cell

transmitter.

In addition, modern mobile phones also support a wide variety of other services such as text messaging, MMS,

email, Internet access, short-range wireless communications (infrared, Bluetooth), business applications, gaming and

photography. Mobile phones that offer these and more general computing capabilities are referred to as smart phones.


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What is a cell site?

A cell site is a geographic area where the base station is located. This is a site composed of antenna tower andelectronic communications equipment placed to create a cell in cellular network for the use of cellular phones.

Bands

All cellular phone networks worldwide use a portion of the radio frequency spectrum designated as ultra high

frequency, or "UHF", for the transmission and reception of their signals. The ultra high frequency band is also shared with

television, Wi-Fi and Bluetooth transmission. The cellular frequencies are the sets of frequency ranges within the ultra

high frequency band that have been allocated for cellular phone use. Due to historical reasons, radio frequencies used for

cellular networks differ in America, Europe, Africa and Asia.


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900 MHz 1800 MHz - Europe, Australia, Africa and Asia

800 MHz - 1900 MHz - United States and other countries

How the cellular phone transmits?

Cellular Phone transmits a certain amount of radio signal. The nearest base station will capture its presence. This

will then able you to receive calls and text essages. On the other hand, if somebody wants to contact you, his/her cellular

phone will transmit a signal to the nearest base station where that person is located. This base station will then transmit to

series of telecommunication relay equipment such as channel towers or satellites until it reaches your base station where

you were connected.
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Previous Topic:

What is cell site?
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Components of a cellular phone

Now you know how the cellular phone sends and receives calls and text messages, you should also be familiar with the

different components of a cellular phone.

I. HARDWAREOutput Components

COMPONENT PHOTO FUNCTION

Cellular Phone

Display

is also called as cellular phone screen. It is made of glass with tiny crystal pixel that

emits light displaying certain information such as text and images.

Types of Cellular Phone Display

- LCD- OLED

- Touch Screen

Speaker

Speaker phone allows the phone to be used at a short distance, without the phone

being held next to the face, (and without using a headset.) It allows a small group of

people near the phone to hear and participate in the conversation. It is also useful for

hands-free, safe operation in an automobile, and when on hold for a long period of

time.


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BuzzerThese are also speakers that can generate high audible sound louder than Earpiece

speakers. It also amplifies the ringtones,voice and music more audibly.

Vibra Motor It is made of a tiny motor that conducts vibration when in active mode.

Input Components

Microphonealso known as "mouthpiece, is the component used to intercept and imitate human

voice and sounds to send to a particular receiver or caller.


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Keypad

refers to the number and letter buttons found on a cell phone, for the purposes of

dialling and typing.

Types of keypad

- Multi-tap- refers to a text entry system used by repeatedly pressing the same keyto cycle through the letters for that key.

- Qwerty- is derived sequentially from the first six keys (from left to right) on the far

left portion of a standard keyboard just below the number keys. This is to prevent

people from typing too quickly and jamming various keys.

- Touch Screen it is an electronic display that is sensitive to human touch, allowing

the user to interact by touching pictures and words on the screen.

Types of touch screen

a. Capacitive

b. Resistive

Power

Batteryis used to provide power supply to the PCB circuits and components. The standard

battery Voltage Range is 3.7V and is made of rechargeable Lithium Ion.


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Battery Chargeris a device used to put energy into a secondary cell or rechargeable battery by

forcing an electric current through it.

Peripheral

Cameraused to take pictures and record video clips. The pictures and clips from the camera

phone can then be transferred to and stored in a computer, shared with other mobile

devices and so on.

Bluetoothis a specification for the use of low-power radio communications to wirelessly link

phones, computers and other network devices over short distances.

SD Slots is a slot that allows you to insert a Secure Digital (SD) memory card into a computer,printer or other device. SD cards are commonly used to store images taken on digitalcameras.


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II. SOFTWAREOutput Components

Firmware

Firmware refers to the applications and operating system that control how a cellphone or smartphone operates. It iscalled firmware rather than software to highlight that it is very closely tied to the particular hardware components of a

device. Firmware is generally flashed into a phone's ROM rather than simply being loaded into normal phone storage,

where it could be more easily erased and lost in the event of a crash. Firmware updates are sometimes provided by a

company as a way to f ix bugs or introduce new functionality.

Applications

Apps allow you to customize a phone to your specific set of wants and needs. They are generally easy to find and

install, and once you start using them, will become a necessary part of your mobile life. Business people want to be

connected to their email as well as be able to review documents, track expenses, and maintain lists of contact

information for various groups of people. Common users in general want email, internet access, and depending upon

their preferences, music and games, along with many of the items a business person needs. The needs of both typesof users can be met in a multimedia smartphone with the appropriate apps.

Module 3

Introduction to Soldering


Know what soldering is


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Understand the safety precautions on soldering

Learn how to prepare the soldering iron

IntroductionIn this session, you will learn and understand the importance and use of a soldering iron for repairing cellular phones.

What is Soldering?

Soldering is the process of using a metal alloy with a low melting temperature (solder) to fuse the electrical contacts of a

component to the pads of a circuit board.

NOTE:

Proper solderingmaximizes the strength and conductivity of the connection; and

Poor solderingcan result in weak connections, higher resistance that causes heat build-up at the connection, and possible

failure of the component.

Hot air Gun and Soldering Iron Temperature Setting

Hot air temperature tends to be variable when working on any SMD components. Various Cellular PhonesProducts use different kinds of solders.

The amount of temperature on Hot Air Gun's common setting is between 250-350 degrees Celsius while Soldering

Iron is between 200 - 280 degrees Celsius.


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Tips for soldering surface mount chip componentCellular phone components need proper techniques of repairing. There are guidelines to keep in mind.

Chip Resistors

The component body of chip resistors is made out of alumna; an extremely hard, white colored material. The resistive

material is normally located on the top. Chip resistors are usually mounted with the resistive element facing upwards to help

dissipate heat.Ceramic Capacitors

These components are constructed from several layers of ceramic with internal metalized layers. Because metal heats

up much faster than ceramic, ceramic capacitors need to be heated slowly to avoid internal separations between the ceramic

and the metal layers.


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NOTE: Avoid rapid heating of ceramic chip capacitors during soldering operations.

Plastic Body

Another style of chip component has a molded plastic body that protects the internal circuitry. There are a number ofdifferent types of components that share this type of exterior package. The termination styles for plastic chip component

packages vary considerably.

MELF - Metal Electrode Face cylindrical components

These may be capacitors, resistors, and diodes. It can be hard to tell them apart - since there is no universal coloring or

component designators printed on the component bodies.

Safety Precautions

Before proceeding to soldering, these are some safety precautions that you need to know:

I. Never touch the tip of the soldering iron.It will give a nasty burn since it is very hot at about 400 Degree Celsius.

II. Avoid touching the mains flex with the tip of the iron.Ordinary plastic flex could easily melt once touched by a hot iron and this will cause serious risk of burns and electric shock.

III. Keep the soldering iron to its stand when not in use.Never put it down on your workbench, even for a moment!

IV. Work in a well-ventilated area.

The smoke formed as you melt solder is mostly from the f lux and quite irritating. Avoid breathing it by keeping you head tothe side of, not above, your work.V. Always wash your hands after using a solder.

A Solder contains lead which is a poisonous metal.

Lesson 2

What is a Circuit Board?


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Know what a circuit board is

Identify the different components on the Printed Circuit Board.

Understand the diagrams of a Printed Circuit Board

Learn the different circuit symbols

Introduction

In this session, you will learn the function of a Printed Circuit Board (PCB) and identify the components within the PCB.

Printed Circuit Board (PCB)

A printed circuit board is one the main components of a cellular phone. It is considered to be the brain area of the

cellular phone and it runs the whole system. A printed circuit board has to be very sturdy to be able to support its

components.

A printed circuit board is used to connect the electric components with the use of conductive pathways and signal

traces through the use of electricity.


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Printed Circuit Board (PCB) Components

A printed circuit board consists of several components that work together to ensure the proper functioning of the cellular

phone.

COMPONENT PHOTO FUNCTION


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ResistorUsed to limit the flow of current. It has no polarity and is checked by continuitytesting (analog or digital type tester). (color; black and shiny, blue or violet)

InductorUsed together with capacitors as current filters. It has no polarity and is checkedby continuity testing (analog or digital type tester). (color; gray or black but notshiny)

FuseUsed to protect the unit from overload. It has no polarity and is checked bycontinuity testing (analog or digital type tester). (color; black or white with "K")

Diodeacts as rectifier. It has polarity and is checked by one-sided continuity testing.(color; black with stripe at one end)


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Capacitor

Used as voltage filters and can store small amount of electricity. It has polarityand is checked by one-sided continuity testing. (color; yellow or black with clearmarkings at the back with stripe on one side for polarized capacitors and brown

for non-polarized capacitors)

Transistor Used to amplify voltages. (color; black, it has 3, 5, or 6 pins)

Light EmittingDiode (LED)

Used to illuminate the LCD and keypads. Commonly known as Backlights. Lightson when checking continuity.


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SpeakerConverts electrical signals into audible sound. Has cracking sound when testingcontinuity.

Microphoneconverts audible sound into electrical signals. Checked using one-sidedcontinuity test.

Integrated Circuit(IC)

performs multi-task function.Types of IC Packaging:

a. Pin type - uses legs made of pins and can be Single In-Line Package (SIP) orDual In-Line Package(DIP)

b. BGA (Ball Grid Array) - uses legs made of solder ball.

Diagrams

Diagram is also known as electronic schematic. It is a graphical representation of electrical circuit. It shows the flow of

connections between the devices using circuit symbols, including the power and signal connections.


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Types of Diagram

Block Diagram

Block diagrams are used to understand (and design) complete circuits by breaking them down into smaller sections or

blocks. Each block performs a particular function and the block diagram shows how they are connected together. No attempt is

made to show the components used within a block, only the inputs and outputs are shown. This way of looking at circuits is

called the systems approach.

Circuit Diagram

Circuit diagrams show how electronic components are connected together. In a circuit diagram, each component is

represented using circuit symbols.


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PCB Diagram

PCB Diagram is a graphical representation on how the components are arranged into the printed circuit board.


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not

connected.

CellSupplies electrical energy. The larger terminal (on the left) is positive (+). A singlecell is often called a battery, but strictly a battery is two or more cells joined together.

BatterySupplies electrical energy. A battery is more than one cell. The larger terminal (onthe left) is positive (+).
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DC supply Supplies electrical energy. DC = Direct Current, always flowing in one direction.

AC supply Supplies electrical energy. AC = Alternating Current, continually changing direction.

FuseA safety device which will 'blow' (melt) if the current flowing through it exceeds aspecified value.

TransformerTwo coils of wire linked by an iron core. Transformers are used to step up (increase)and step down (decrease) AC voltages. Energy is transferred between the coils bythe magnetic field in the core. There is no electrical connection between the coils.

Earth(Ground)A connection to earth. For many electronic circuits, this is the 0V (zero volts) of thepower supply, but for mains electricity and some radio circuits it really means theearth. It is also known as ground.

Wires & Connections

Circuit symbols are used in circuit diagrams which show how a circuit is connected together. The actual layout of the

components is usually quite different from the circuit diagram. To build a circuit you need a different diagram showing the layout

of the parts on a strip board or printed circuit board.

Output Devices

COMPONENT CIRCUIT SYMBOL FUNCTION

Lamp (lighting)A transducer which converts electrical energy to light. This symbol is used for a lamp

providing illumination, for example a car headlamp or torch bulb.

Lamp (indicator)A transducer which converts electrical energy to light. This symbol is used for a lamp

which is an indicator, for example a warning light on a car dashboard.


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Heater A transducer which converts electrical energy to heat.

Motor A transducer which converts electrical energy to kinetic energy (motion).

Bell A transducer which converts electrical energy to sound.

Buzzer A transducer which converts electrical energy to sound.

Inductor(Coil,

Solenoid)

A coil of wire which creates a magnetic field when current passes through it. It may

have an iron core inside the coil. It can be used as a transducer converting electrical

energy to mechanical energy by pulling on something.


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Output Devices

Circuit symbols are used in circuit diagrams which show how a circuit is connected together. The actual layout of thecomponents is usually quite different from the circuit diagram. To build a circuit you need a different diagram showing the layout


Switches


Push Switch

(push-to-make)A push switch allows current to flow only when the button is pressed. This is the

switch used to operate a doorbell.

Push-to-Break

SwitchThis type of push switch is normally closed (on), it is open (off) only when the

button is pressed.

On-Off Switch

(SPST)SPST = Single Pole, Single Throw. An on-off switch allows current to flow only

when it is in the closed (on) position.

2-way Switch

(SPDT)

SPDT = Single Pole, Double Throw. A 2-way changeover switch directs the flow

of current to one of two routes according to its position. Some SPDT switches

have a central off position and are described as 'on-off-on'.

Dual On-Off

Switch (DPST)

DPST = Double Pole, Single Throw. A dual on-off switch which is often used to

switch mains electricity because it can isolate both the live and neutral

connections.


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Reversing Switch

(DPDT)DPDT = Double Pole, Double Throw. This switch can be wired up as a reversing

switch for a motor. Some DPDT switches have a central off position.

RelayAn electrically operated switch, for example a 9V battery circuit connected to the

coil can switch a 230V AC mains circuit. NO = Normally Open, COM = Common,

NC = Normally Closed.

Switches


components is usually quite different from the circuit diagram. To build a circuit you need a different diagram showing the layout


Resistors


ResistorA resistor restricts the flow of current, for example to limit the current passing

through a LED. A resistor is used with a capacitor in a timing circuit.

Variable Resistor

(Rheostat)

This type of variable resistor with 2 contacts (a rheostat) is usually used to control

current. Examples include: adjusting lamp brightness, adjusting motor speed, and

adjusting the rate of flow of charge into a capacitor in a timing circuit.


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Variable Resistor

(Potentiometer)

This type of variable resistor with 3 contacts (a potentiometer) is usually used to

control voltage. It can be used like this as a transducer converting position (angle of

the control spindle) to an electrical signal.

Variable Resistor

(Preset)

This type of variable resistor (a preset) is operated with a small screwdriver or

similar tool. It is designed to be set when the circuit is made and then left without

further adjustment. Presets are cheaper than normal variable resistors so they are

often used in projects to reduce the cost.

Capacitors


components is usually quite different from the circuit diagram. To build a circuit you need a different diagram showing the layoutof the parts on a strip board or printed circuit board.

Capacitors


CapacitorA capacitor stores electric charge. A capacitor is used with a resistor in a timing circuit.

It can also be used as a filter, to block DC signals but pass AC signals.

Capacitor,

polarised

A capacitor stores electric charge. This type must be connected the correct way round.

A capacitor is used with a resistor in a timing circuit. It can also be used as a filter, to

block DC signals but pass AC signals.


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Variable

CapacitorA variable capacitor is used in a radio tuner.

TrimmerCapacitor

This type of variable capacitor (a trimmer) is operated with a small screwdriver orsimilar tool. It is designed to be set when the circuit is made and then left without

further adjustment.

Transistors

Circuit symbols are used in circuit diagrams which show how a circuit is connected together. The actual layout of the components is

usually quite different from the circuit diagram. To build a circuit you need a different diagram showing the layout of the parts on astrip board or printed circuit board.

Transistors

COMPONENTCIRCUIT

SYMBOLFUNCTION

Transistor NPNA transistor amplifies current. It can be used with other components to make an amplifier or switching

circuit.


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Transistor PNPA transistor amplifies current. It can be used with other components to make an amplifier or switching

circuit.

Phototransistor A light-sensitive transistor.

Circuit Symbols

Circuit symbols are used in circuit diagrams which show how a circuit is connected together. The actual layout of the components is

usually quite different from the circuit diagram. To build a circuit you need a different diagram showing the layout of the parts on a

strip board or printed circuit board.

Audio and Radio Devices



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Microphone A transducer which converts sound to electrical energy.

Earphone A transducer which converts electrical energy to sound.

Loudspeaker A transducer which converts electrical energy to sound.

Piezo Transducer A transducer which converts electrical energy to sound.

Amplifier (general

symbol)

An amplifier circuit with one input.It is a block diagram symbol because it represents a

circuit rather than just one component.


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Aerial (Antenna)A device which is designed to receive or transmit radio signals. It is also known as an

antenna.

Lesson 3

How to Solder?

Session Objectives


Know the proper techniques of Soldering

Learn the safety precautions on soldering

Understand what a circuit board is and its components

Learn the circuit symbols

Introduction

In this session, you will learn, understand and perform the basic steps for soldering different internal components of a cellular phone


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Basic Procedure on How to Solder

Note: Please keep in mind safety precautions.

Step 1: Clean the surface of the PCB

A clean surface is very important for a strong, low resistance solder joint.

Step 2: Component Placement In general it is best to start with the smallest and flattest components (resistors, ICs, signal diodes, etc.) and then

work up to the larger components (capacitors, power transistors, transformers) after the small parts are done.

Step 3: Apply Heat

Apply a very small amount of solder to the tip of the iron. This helps conduct the heat to the component and board, but it is not the solder that

will make up the joint.

Step 4: Apply Solder To The Joint

Once the component lead and solder pad have heated up, you are ready to apply solder. Touch the tip of the strand of solder to the componentlead and solder pad, but not the tip of the iron. If everything is hot enough, the solder should flow freely around the lead and pad. You will see

the flux melt liquify as well, bubble around the joint (this is part of its cleaning action), flow out and release smoke. Continue to add solder to the

joint until the pad is completely coated and the solder forms a small mound with slightly concave sides. If it starts to ball up, you have used too

much solder or the pad on the board is not hot enough.

Step 5: Inspect The Joint and Cleanup

Once the joint is made, you should inspect it. Check for shorts with adjacent pads or poor flow. If the joint checks out, move on to the next.

Previous Topic:

Introduction

Nex:

Basic De-soldering Procedure
http://116.50.136.25/CP_Repair/M3_L3_introduction.htmlhttp://116.50.136.25/CP_Repair/M3_L3_introduction.htmlhttp://116.50.136.25/CP_Repair/M3_L3_introduction.htmlhttp://116.50.136.25/CP_Repair/M3_L3_introduction.htmlhttp://116.50.136.25/CP_Repair/M3_L3_desoldering.htmlhttp://116.50.136.25/CP_Repair/M3_L3_desoldering.htmlhttp://116.50.136.25/CP_Repair/M3_L3_desoldering.htmlhttp://116.50.136.25/CP_Repair/M3_L3_desoldering.htmlhttp://116.50.136.25/CP_Repair/M3_L3_desoldering.htmlhttp://116.50.136.25/CP_Repair/M3_L3_desoldering.htmlhttp://116.50.136.25/CP_Repair/M3_L3_desoldering.htmlhttp://116.50.136.25/CP_Repair/M3_L3_introduction.htmlhttp://116.50.136.25/CP_Repair/M3_L3_introduction.htmlhttp://116.50.136.25/CP_Repair/M3_L3_introduction.html


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Basic De-soldering ProcedureA. Using a de-soldering pump (solder sucker)

Step 1:

In setting up the pump, you need to push the spring-loaded plunger down until it locks.

Step 2:

Apply both the pump nozzle and the tip of your soldering iron to the joint.

Step 3:

Wait a second or two for the solder to melt.


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Step 4:

Then press the button on the pump to release the plunger and suck the molten solder into the tool.

Step 5:

Repeat if necessary to remove as much solder as possible.

Step 6:

The pump will need emptying occasionally by unscrewing the nozzle.

Basic De-soldering ProcedureB. Using solder remover wick (copper braid)

Step 1:

Apply both the end of the wick and the tip of your soldering iron to the joint.

Step 2:

As the solder melts, most of it will flow onto the wick, away from the joint.

Step 3:

Remove the wick first, then the soldering iron.

Step 4:

Cut off and discard the end of the wick coated with solder.


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Soldering circuit board components

1. IC Holder

Place the IC holder into the circuit board, so that the leads on the bottom extend all the way throughthe holes in the board. Do not attach the IC to the holder yet. Turn the circuit board over so that the

bottom is facing up, and heat your soldering iron. Then solder each one of its lead. Use enough solder,

this will prevent the solder to pull back from the board. After soldering all its lead, let it cool for a

second.

2. Resistors

Soldering a resistor is not difficult. You just need to solder the two ends of its lead to the board.

3. Capacitor

Place your capacitor lead to the circuit board. Bend the leads down to hold the capacitor in place as

you are soldering. Make sure the capacitor is as tight to the board as possible. Touch the soldering ironto the joint it is sitting on. And wait for a few seconds to let it cool.


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4. Inductor

Center the electronic component on the circuit board mounting pads. For thru-hole components, feed

the leads through the holes and bend the end of the lead over to hold it in place. Apply the solder to thelead. Do not move the component or board until the solder connection cools for a few seconds.

MODULE 4 INTRODUCTION TO DIAGNOSTIC REPAIR

Session Objectives


Know the safety equipment and tools used to repair cellular phone.

Install and Connect the Z3X Box

Apply the Standard Operating Procedure before performing cellular phone repair

Introduction

In this session you will learn the safety equipment and tools used for diagnosing and repairing faulty cellular phones.

OHS Equipment

1. Anti-static Wrist Strap

Anti static wrist strap is used to avoid risk of electrostatic discharge from a human body to an electronic component circuit.


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2. Hand Gloves

Protect your hand from possible burns or brushes. It also protect the cell phones from scratches and possible electrostatic discharge

Antistatic Wrist Strap

Diagnostic procedures

External Diagnosis

It is the diagnostic process of examining the external components of the cellular phone.

Software Diagnosis


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It is the diagnostic process of examining the phone using software.

Internal Diagnosis It is the diagnostic process of examining the internal components of the cellular phone.

Diagnostic tools

HAND TOOL PICTURE FUNCTIONS

Multitester (Analog/Digital) Used to measure Voltages, Currents and Resistance in electronic components.

Screw Drivers Used to loosen and tighten the phones screws.


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Tweezers Used to hold and pick small cell phone component parts.

Pick tool Used to open cellular phone's cover

Soldering Iron Used to solder / resolder electronic parts.


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Soldering Lead Used to bond Electronic components

Jumper Wires Used to jump connections of the components within the PCB.

Soldering Flux and Paste Used to tighten soldering quality.

BGA Rework Station Applied Heat to remove and replace parts and IC chips.


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DC Regulated Power Supply Used to substitute battery voltage when working on hardware troubleshooting.

Software

1. Flashing and Unlocking Device- it is Software Tools used to unlock and flash mobile phones programmable circuits. Examples of these types of

devices are: Micro-HWK, Z3X Box, and Cyclone Box.

How to install the software and drivers for the Z3X Box

I. Download the Z3X Box Shell software from the official website at www.z3x-team.com

II. After downloading the Z3X Box Shell software, double click on the executable file. This will install the necessary software to use Z3X Box.

III. After the installation of the Shell software, connect the Z3X box to a free USB port on your computer.

IV. When the box is connected, you will need to install the windows device drivers for the Z3X Box to function properly.

Procedures on how to install the device driver for Z3X Box: Z3X Box

I. Click start and right click on Computer, then click on Properties.

A new window will appear displaying information about your Computer. On the upper left corner of the windows click on Device Manger.


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II. On the Other devices list, locate and right click on the Z3X BOX icon and click on Properties.

III. On the Z3X Box Properties windows, click on the Driver tab and then Click on the Update Driver button.

IV. A dialog box will appear asking you How do you want to search for driver software, click on the Browse my computer for driver software

option.

V. On the Browse for driver software on your computer windows, click on the Browse button and locate C: \Program Files\Z3X\Box Drivers,

then click ok.

VI. Windows will now install the Z3X Box driver, a message box will appear informing you that Windows cant verify the publisher of this driver

software, click on the Install this driver software anyway option. Wait for Windows to complete the driver installation.

VII. After installing the driver for the Z3X Box, a new device will appear on the list of Other devices. Right click on the USB Serial Port icon and

click on Properties, follow the instructions d g to install the driver for the USB Serial Port device.

Smart Card

I. Next, you will need to install the device for the Smart Card, on the Other devices list locate and right click on the Smart Card icon

and click on Properties.

II. On the Smart Card Properties windows, click on the Driver tab and then Click on the Update Driver button.

III. A dialog box will appear asking you How do you want to search for driver software, click on the Browse my computer for driver software

option.

IV. On the Browse for driver software on your computer windows, click on the Let me pick from a list of device on my computer option.

V. Scroll down on the list of Common hardware types: and click on Smart Cards, then click the Next button.

VI. From the Manufacturer list select Microsoft , from the Model list select Generic Smart Card and click the Next button.

VII. An Update Driver Warning dialog box will appear, just click on the Yes button to continue installing the driver.


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VIII. After the installation is finished, click on the Close button.

IX. After completing the installation of the drivers, you will need to register and activate your Z3X Box. To this make sure that you are connected

to the internet.

X. Run the Z3X Box shell, click on the Settings and Card tools tab. Click on the Run Card Wizard button and follow the on sc reen instructions.

Standard Operating Procedure Before Conducting Repairs

I. Know the phone's history

Conduct an interview with the cellular phone owner to know what had happened before the problem first occurred.

II. Check the phones status

Perform an external inspection of the phone to get an idea of the possible cause of the problem.

III. Make an assessment if the phone is still fixable or not.

IV. Inform the customer about the problem, possible solution, and service fee

Explain to the customer what exactly you are going to do with the cellular phone and give an estimate repair cost.

Lesson 2

Hardware Problems

Session Objective


Perform diagnostics and repair common cellular phone problems


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Introduction

In this session, you will learn how to diagnose and repair faulty cellular phones.

How to Disassemble Samsung Chat E222Tools:

1. Precision Philips Screw driver

II. Pick tool

Procedure:

I. Make sure that the cellular phone is turned off.

II. Remove the back cover, battery and sim card.

III. Using a Philips Screw driver unscrew all six (6) screws.

IV. Separate the rear case. Using a pick tool unhook the nine (9) hook points of the case.

V. Detach the LCD flex connector from the PCB.

VI. Detach the PCB from the front case

VII. Remove the shield plating from the PCB

VIII. Remove the Keypad and LCD from the front case


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How to Aassemble Samsung Chat E222

Tools:

1. Precision Philips Screw driver

II. Pick tool

Procedure:

I. Attach the Keypad and LCD into the front case.

II. Attach the shield plating into the PCB.

III. Attach the PCB into the front case.

IV. Connect the LCD Flex connector into the PCB LCD panel.

V. Assemble the rear case.

VI. Using a Philips Screw driver fasten all six (6) screws.

VII. Insert the sim card and battery.

VIII. Place the back cover.

Common Problems

Hardware Problem:

NO AUDIO RECEIVED

Diagnosis and Repair Procedure

I. Turn on the phone and dial 112 to test if you can hear audio.


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II. Disassemble the phone to expose the ear piece.

III. Check for corrosion on the contact points, clean with soft bristle brush with contact cleaner.

IV. Check for contact points continuity. If there is no continuity, re-solder the contact points.

V. After re-soldering, check continuity again.

VI. If it still doesnt work, replace the ear piece.

Common Problems

Hardware Problem:

NO AUDIO TRANSMITTED


I. Disassemble the phone to expose the microphone.

II. Check for corrosion on the contact points, clean with soft bristle brush with contact cleaner.

III. Check for contact points continuity. If there is no continuity, re-solder the contact points.

IV. After re-soldering, check continuity again.

V. If it still doesnt work, replace the microphone.

Common Problems

Hardware Problem:

INSERT SIM CARD



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I. Remove the back cover of the phone and locate the SIM Card Slot.

II. Check for continuity of the contact points.

III. If there is no continuity, disassemble the phone.

IV. Check for corrosion on the contact points of the SIM card slot going to the PCB.

V. If there are corrosion, clean with soft bristle brush WITH contact cleaner.

VI. Check the continuity from the SIM card slot going to the IC controller.

VII. If there is no continuity, replace the IC.

Documents

Cellular Phone Technician