Yoyoy 2 - CBLM COMMON TEST ELECTRONIC COMPONENTS

COMPETENCY-BASED
LEARNING MATERIALS
Sector:
ELECTRONICS
Distinctive Area of Competence/Qualifications:
ELECTRONIC PRODUCT ASSEMBLY AND SERVICING NC II
Unit of Competency:
TEST ELECTRONIC COMPONENTS
Module Title:
TESTING ELECTRONIC COMPONENTS
Name of Institution:
OLEVIROS COLLEGE INCORPORATED
San Francisco Iriga City
Upon completion of these information sheets, you will be able to:

Identify tools needed for cellular repair
Prepare repair workplace properly
TOOLS
1. Hot air soldering station – use for soldering/desoldering SMD components using hot air.
2. Torx screwdriver – special type of srewdriver used primarily in loosening cellphone unit
screws.
3. Multimeter – instrument used in checking or testing components and PCB trace. Is also used
in measuring resistance, voltage and current.
22
INFORMATION
SHEETS 4.2.1
USE AND FUNCTION OF TOOLS,
EQUIPMENT AND TESTING
INSTRUMENTS
N.C. LEVEL : II
CORE MODULE: 4 LO: 2
STS
QA
SYSTEM
IDENTIFY AND EXPLAIN THE
USES/FUNCTIONS OF
DIFFERENT TYPES OF TOOLS
AND TESTING INSTRUMENTS
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
Document No. CES-NC2-CORE-M4-LO2-INFO1
Issued by: STS Date: 11/12/2010
Revision: 1 Page 2 of 8
4. Tweezer – used to hold or get components.
5. Soldering flux – a gel used over an SMD to prevent excessive heat transferred to the
component.
6. BGA paste – a paste used during BGA rework to replenish lost solder when cleaning the
BGA terminals.
Flux
BGA paste
23
INFORMATION
SHEETS 4.2.1
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
1
7. Maintenance Plate – a plate primarily used as platform for a cellphone unit board during
hardware repair.
8. Flasher/Unlocker toolbox – a box connected to a PC used for flashing and unlocking newer
models of cellphone units.
9. Soldering Iron - a soldering iron is a tool normally used for applying heat to two or more
adjoining metal parts such that solder may melt and flow between those parts, binding them
securely, conductively and hermetically.
Flasher/Unlocker
toolbox
Phone Cable
USB Cable
BGA preform
Maintenance
Plate base
Maintenance
Plate board
stands
24
INFORMATION
SHEETS 4.2.1
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
10. Soldering Lead - soldering lead is used to bond or connect electronic components.
11. Soldering Paste - solder paste (or solder cream) is used for connecting the terminations of
integrated chip packages with land patterns on the printed circuit board.
12. Soldering Wick - a solder wick (also desoldering wick or desoldering braid) is a tool for
removing solder from any solder joint. Usually, it is a roll of fine, braided 18 to 42 AWG wire,
typically oxygen free copper, which has been treated with a rosin solder flux.
25
INFORMATION
SHEETS 4.2.1
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
2
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
13. Adjustable DC Powers Supply - the Dc power Supply can be used to substitute for the
Battery Voltage when do live voltage checking on the PCB circuits... This is being used to
trace the power supply line in electronic circuit.
Here's a sample of substituting DC voltage in working cellphone repair tracing B+ line.
14. Re-balling Kits - Re-balling kits are used to repair broken or weak soldered BGA (Ball Grid
Array) Chips. This is very important tools when it comes to hardware problem
troubleshooting in various mobile phones. This is only being used when an IC or chips was
being suspected having fault or causes the problem. That is because Mobile phones used
BGA (ball grid array) solder balls that holds as connection terminal of every chips.
26
INFORMATION
SHEETS 4.2.1
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
27
INFORMATION
SHEETS 4.2.1
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
3
15. A Cleaning liquid - a lacquer thinner will work, and still widely used for many mobile phone
technician.
16. Personal Computer may help for storing support guides and manuals, A PC is also the key
tool when it comes working on software like flashing and unlocking mobile phones. It is also
being used to apply any applications such as Themes, Games, Mp3 music and ring-tones
and any other application and add-ons to the cellphones by using a USB cable wire or bluetooth
device attach to it. A large Memory storage or Hard disk is also required for storing
many softwares and programs just only for mobile phones.
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INFORMATION
SHEETS 4.2.1
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
17. Table lamp is also require on a working table, it adds visibility when fixing things on a table
like cellphone because cellphone parts are too small enough to handle.
A magnifying lamp is much better for repairing tiny parts on a cellphone specially when it
comes working on soldering a component and to avoid risk of damaging to other parts.
29
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
Objective(s):
4
Operate testing instruments properly
How to use a Multimeter
- The basics or instructions of how to use a multimeter, including how to use an analog or
analogue
multimeter, or a digital multimeter, DMM, and using multimeters their best advantage.
Multimeters are very cheap to buy and are one of the most commonly used pieces of electronics
test equipment. Although basic operational multimeter instruction may be given when the test
meter
is bought, details of how to use the multimeter to test circuits and gain the maximum use from
them
are not always available.
Although there are major differences between the internal circuits within analogue and digital
multimeters, the way in which they are used is comparatively similar. However separate sections
are given below with instructions on how to use a digital multimeter and how to use an analogue
multimeter.
How to use a digital multimeter
The operation of a DMM, digital multimeter, itself is normally very straightforward. With a
knowledge
of how to make voltage, current and resistance measurements (see the "Related Articles" on the
left
hand side of this page for further details) it is then a matter of putting the multimeter to use. If the
meter is new then it will obviously be necessary to install a battery to power it. This is normally
simple and straightforward and details can be found in the operating instructions for the DMM.
... apart from amps, volts, and ohms, many
DMMs can measure parameters including
frequency, capacitance, continuity, and
temperature....
30
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
When using the meter it is possible to follow a number of simple steps:
1. Turn the meter on
2. Insert the probes into the correct connections - this is required because there may be a
number
of different connections that can be used.
3. Set switch to the correct measurement type and range for the measurement to be made.
When
selecting the range, ensure that the maximum range is above that anticipated. The range on
5
the DMM can then be reduced as necessary. However by selecting a range that is too high, it
prevents the meter being overloaded.
4. Optimise the range for the best reading. If possible enable all the leading digits to not read
zero,
and in this way the greatest number of significant digits can be read.
5. Once the reading is complete, it is a wise precaution to place the probes into the voltage
measurement sockets and turn the range to maximum voltage. In this way if the meter is
accidentally connected without thought for the range used, there is little chance of damage to
the meter. This may not be true if it left set for a current reading, and the meter is accidentally
connected across a high voltage point!
How to use an analogue multimeter
The operation of an analogue multimeter is quite easy. With a knowledge of how to make
voltage,
current and resistance measurements (see the "Related Articles" on the left hand side of this
page
for further details) it is only necessary to know how to use the multimeter itself. If the meter is
new
then it will obviously be necessary to install any battery or batteries needed for the resistance
measurements.
... analogue multimeters have been available for
many years and they are very flexible in their
operation....
31
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
number
of different connections that can be used. Be sure to get the right connections, and not put
them into the ones for a low current measurement if a high voltage measurement is to be made
- this could damage the multimeter.
2. Set switch to the correct measurement type and range for the measurement to be made.
When
selecting the range, ensure that the maximum for the particular range chosen is above that
anticipated. The range on the multimeter can be reduced later if necessary. However by
selecting a range that is too high, it prevents the meter being overloaded and any possible
damage to the movement of the meter itself.
3. Optimise the range for the best reading. If possible adjust it so that the maximum deflection of
the meter can be gained. In this way the most accurate reading will be gained.
6
measurement sockets and turn the range to maximum voltage position. In this way if the meter
is accidentally connected without thought for the range to be used, there is little chance of
damage to the meter. This may not be true if it left set for a current reading, and the meter is
accidentally connected across a high voltage point!
Measuring voltage with a multimeter
- an overview or tutorial about how to measure voltage with a digitial multimeter (DMM) or an
analogue multimeter.
One the important measurements that it is possible to make with a multimeter (either and analog
/
analogue multimeter) or a digital multimeter is that of voltage. Voltage measurements look at the
potential difference between two points. In other words they look at the difference in electric
pressure at the two points. In most cases the voltage is measured between a particular point
and
the ground or zero volt line on a circuit. However this does not mean that the voltage cannot be
measured between any two points.
When making a voltage measurement with a multimeter, the first step is to switch the multimeter
to
the voltage ranges. It is best to select a range higher than the expected voltage so that there is
no
chance of the meter being overloaded and damaged. In addition to this check that the test leads
are
plugged into the correct sockets. Many multimeters have different sockets for different types of
measurement so it is worth checking the correct ones have been chosen before making the
measurement. Usually a meter will be provided with two leads, one black, and the other red. The
black one is normally taken as the negative one. It is connected to the negative or "common"
socket
on the meter. The red one is connected to the positive socket.
When making the measurement, the positive lead should be connected to terminal which is
expected to have the more positive voltage. If the leads are connected the wrong way round a
negative voltage will be displayed. This is acceptable for a digital multimeter (DMM) because it
will
32
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
just display a negative sign. However for an analogue multimeter, the meter needle will move
backwards and hit a stop. If at all possible it is best not to allow this to happen.
With the multimeter connected, power can be applied to the circuit. The multimeter switches can
7
then be changed to reduce the value of the range. This is done until the largest deflection is
seen on
the meter without it going over the top of the range. In this way the most accurate reading is
obtained.
How to measure current
- an overview or tutorial about how to measure electrical current with a digital multimeter (DMM)
or
an analogue multimeter. This includes how to direct electrical current and how to measure ac
current with a multimeter.
It is often necessary to know how to measure current using a multimeter. Current measurements
are easy to make, but they are done in a slightly different way to the way in which voltage and
other
measurements are made. However current measurements often need to be made to find out
whether a circuit is operating correctly, or to discover other facts associated with its current
consumption.
Current measurements can be made with a variety of test instruments, but the most widely used
pieces of test equipment for making current measurements is a digital multimeter. These items
of
test equipment are widely available and at very reasonable prices.
Basics of current measurement
Current measurements are made in a different way to voltage and other measurements. Current
consists of a flow of electrons around a circuit, and it is necessary to be able to monitor the
overall
flow of electrons. In very simple circuit is shown below. In this there is a battery, a bulb which
can be
used as an indicator and a resistor. To change the level of current flowing in the circuit it is
possible
to change the resistance, and the amount of current flowing can be gauged by the brightness of
the
bulb.
A simple circuit in which to measure current
33
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
When using a multimeter to measure current, the only way that can be used to detect the level
of
current flowing is to break into the circuit so that the current passes through the meter. Although
this
8
can be difficult at times, it is the best option. A typical current measurement can be made as
shown
below. From this it can be seen that the circuit in which the current is flowing has to be broken
and
the multimeter inserted into the circuit. In some circuits where current may often need to be
measured, terminals with a shorting link may be added to facilitate the current measurement.
How to measure current using a multimeter
In order that the multimeter does not alter the operation of the circuit when it is used to measure
current, the resistance of the meter must be as low as possible. For measurements of around an
amp, the resistance of a meter should be much less than an ohm. For example if a meter had a
resistance of one ohm, and a current of one amp was flowing, then it would develop a voltage of
one volt across it. For most measurements this would be unacceptably high. Therefore
resistances
of meters used to measure current are normally very low.
How to measure current with an analogue multimeter
It is quite easy to use an analogue meter to measure electrical current. There are a few minor
differences in way that current measurements are made, but the same basic principles are used.
number
of different connections that can be used. Be sure to get the right connections as there may be
separate connections for very low or very high current ranges.
2. Set switch to the correct measurement type (i.e. to measure current) and range for the
measurement to be made. When selecting the range, ensure that the maximum for the particular
range chosen is above that anticipated. The range on the multimeter can be reduced later if
necessary. However by selecting a range that is too high, it prevents the meter being
overloaded
and any possible damage to the movement of the meter itself.
34
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
3. When taking the reading, optimise the range for the best reading. If possible adjust it so that
the
maximum deflection of the meter can be gained. In this way the most accurate reading will be
gained.
measurement sockets and turn the range to maximum voltage position. In this way if the meter
is
9
accidentally connected without thought for the range to be used, there is little chance of damage
to
the meter. This may not be true if it left set for a current reading, and the meter is accidentally
How to measure current with a digital multimeter
To measure current with a digital multimeter it is possible to follow a few simple steps:
1. Turn the meter on
2. Insert the probes into the correct connections - in many meters there are a number of different
connections for the probes. Often one labelled common into which the black probe is normally
placed. The other probe should be entered into the correct socket for the current measurement
to
be made. Sometimes there is a special connection for current measurements, and sometimes a
separate one for either low or high current measurements. Select the correct one for the current
measurement to be made.
3. Set main selector switch on the meter switch to the correct measurement type, (i.e. current)
and
range for the measurement to be made. When selecting the range, ensure that the maximum
range
is above the expected reading anticipated. The range on the DMM can then be reduced as
necessary. However by selecting a range that is too high, it prevents the meter being
overloaded.
4. When the measuring the current, optimise the range for the best reading. If possible enable
all
the leading digits to not read zero, and in this way the greatest number of significant digits can
be
read.
measurement sockets and turn the range to maximum voltage. In this way if the meter is
accidentally connected without thought for the range used, there is little chance of damage to
the
meter. This may not be true if it left set for a current reading, and the meter is accidentally
Following these steps it is very easy to measure current using any digital multimeter.
35
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
How to measure resistance with a multimeter
- an overview or tutorial about measuring resistance with a digital multimeter (DMM) or an
analogue
10
multimeter.
One important measurement that can be made with a multimeter is a resistance measurement.
Not
only can these be made to check the accuracy of a resistor, or check it is functioning correctly,
but
resistance measurements can be required in many other scenarios as well. It may be to
measure
the resistance of an unknown conductor, or it may be to check for short circuits and open
circuits. In
fact there are many instances where measuring resistance is of great interest and importance.
In all
these cases a multimeter is an ideal piece of test equipment for measuring resistance
Basics of measuring resistance
When measuring resistance, all musltimeters use exactly the same principle whether they are
analogue multimeters or digital multimeters. In fact other forms of test equipment that measure
resistance also use the same basic principle.
The basic idea is that the multimeter places a voltage at the two probes and this will cause a
current
to flow in the item for which the resistance is being measured. By measuring the resistance it is
possible to determine the resistance between the two probes of the multimeter, or other item of
test
equipment.
How to measure resistance with an analogue multimeter
Analogue multimeters are good at measuring resistance, although they are a few points to note
about the way in which it is done. The first point to note is that as the meter itself responds to
current flowing through the component under test, a high resistance which corresponds to a low
current appears on the left hand side of the dial, and a low resisatnce which corresponds to a
higher
current appears on the right hand side of the dial as shown below. It will also be noticed that the
calibrations become much closer together as the resistance becomes higher, i.e. on the left
hand
side of the dial.
Another aspect of using an analogue multimeter for measuring resistance is that the meter
needs to
be "zero'ed" before making a measurement. This is done by connecting the two probes together
so
that there is a short circuit, and then using the "zero" control to give full scale deflection on the
meter, i.e. zero ohms. Each time the range is changed, the meter needs to be zero'ed as the
position may change from one range to the next. The meter needs to be zero'ed because the full
scale deflection will change according to aspects such as the state of the battery.
There are a few simple steps required to make a resistance measurement with an analogue
multimeter:
1. Select the item to be measured: This may be anything where the resistance needs to be
measured and estimate what the resistance may be.
36
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
11
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
2. Insert the probes into the required sockets Often a multimeter will have several sockets for
the
test probes. Insert these or check they are already in the correct sockets. Typically these might
be
labelled COM for common and the other where the ohms sign is visible. This is normally
combined
with the voltage measurement socket.
3. Select the required range The analogue multimeter needs on and the required range
selected.
The range selected should be such that the best reading can be obtained. Normally the
multimeter
function switch will be labelled with the maximum resistance reading. Choose the one where the
estimated value of resistance will be under but close to the maximum of the range. In this way
the
most accurate resistance measurement can be made.
4. Zero the meter: The meter needs to be zero'ed. This is done by firmly palcing the two probes
together to give a short circuit and then adjusting the zero control to give a zero ohms (full scale
deflection) reading. This process needs to be repeated if the range is changed.
5. Make the measurement With the multimeter ready to make the measurement the probes can
be applied to the item that needs to be measured. The range can be adjusted if necessary.
6. Turn off the multimeter Once the resistance measurement has been made, it is wise to turn
the function switch to a high voltage range. In this way if the multimeter is used to again for
another
type of reading then no damage will be caused if it is inadvertently used without selecting the
correct
range and function.
Analogue multimeters are ideal pieces of test equipment for measuring resistance. They are
relatively cheap and they offer a reasonably good level of accuracy and general performance.
They
normally provide a level of accuracy that is more than sufficient for most jobs.
How to measure resistance with an digital multimeter, DMM
Measuring resistance with a digital multimeter is easier and faster than making a resistance
measurement with an analogue multimeter as there is no need to zero the meter. As the digital
multimeter gives a direct reading of the resistance measurement, there is also no equivalent of
the
reverse reading found on the analogue multimeters.
There are a few simple steps required to make a resistance measurement with a digital
multimeter:
1. Select the item to be measured: This may be anything where the resistance needs to be
measured and estimate what the resistance may be.
2. Insert the probes into the required sockets Often a digital multimeter will have several sockets
for the test probes. Insert these or check they are already in the correct sockets. Typically these
37
INFORMATION
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
12
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
might be labelled COM for common and the other where the ohms sign is visible. This is
normally
combined with the voltage measurement socket.
3. Turn on the multimeter
4. Select the required range The digital multimeter needs on and the required range selected.
The range selected should be such that the best reading can be obtained. Normally the
multimeter
function switch will be labelled with the maximum resistance reading. Choose the one where the
estimated value of resistance will be under but close to the maximum of the range. In this way
the
most accurate resistance measurement can be made.
5. Make the measurement With the multimeter ready to make the measurement the probes can
be applied to the item that needs to be measured. The range can be adjusted if necessary.
6. Turn off the multimeter Once the resistance measurement has been made, the multimeter
can
be turned off to preserve the batteries. It is also wise to turn the function switch to a high voltage
range. In this way if the multimeter is used to again for another type of reading then no damage
will
be caused if it is inadvertently used without selecting the correct range and function.
Digital multimeters are ideal pieces of test equipment for measuring resistance. They are
relatively
cheap and they offer a high level of accuracy and general performance.
General precautions when measuring resistance
As with any measurement, when measuring resistance, there are some precautions to observe.
In
this way damage to the multimeter can be prevented, and more accurate measurements can be
made.
* Measure resistance when components are not connected in a circuit: It is always advisable not
to measure the resistance of an item that is in a circuit. It is always best to make the
measurement
of the component on its own out of the circuit. If a measurement is made in-circuit, then all the
other
components around it will have an effect. Any other paths that will allow current to pass will
affect
the readings, making them inaccurate to some degree.
* Remember to ensure the circuit under test is not powered on Under some circumstances it is
necessary to measure resistance values actually on a circuit. When doing this it is very
important to
ensure the circuit is not powered on. Not only will any current flowing in the circuit invalidate any
readings, but should the voltage be high enough, the current resulting could damage the
multimeter.
38
INFORMATION
13
SHEETS 4.2.2
INSTRUMENTS
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
* Ensure capacitors in a circuit under test are discharged. Again when measuring resistance
values in a circuit, it is necessary to ensure that any capacitors in the circuit are discharged. Any
current that flows as a result of them will cause the meter reading to be altered. Also any
capacitors
in the circuit that are discharged may charge up as a result of the current from the multimeter
and as
a result it may take a short while for the reading to settle.
* Remember diodes in a circuit will cause different readings in either direction When measuring
resistance in a circuit that includes diodes the value measured will be different if the connections
are
reversed. This is because the diodes only conduct in one direction.
* Leakage path through fingers can alter readings in some cases. When making some
resistance measurements it is necessary to hold a resistor or component onto the multimeter
test
probes. If high resistance measurements are being made the leakage path through the fingers
can
become noticeable. Under some circumstances the resistance path through fingers can be
measured at just a few megohms, and as a result this can become significant. Fortunately the
levels
of voltage used in most multimeters when measuring resistance is low, but some specialised
meters
may use much higher voltages. It is wise to check.
39
SELF CHECK
4.2.1
USES/FUNCTIONS OF DIFFERENT
TYPES OF TOOLS AND TESTING
INSTRUMENTS FOR MAINTAINING AND
REPAIRING CELLULAR PHONES
N.C. LEVEL : II
STS
QA
SYSTEM
USES/FUNCTIONS OF
14
FOR MAINTAINING AND
REPAIRING CELLULAR
PHONES
Document No. CES-NC2-CORE-M4-LO2-SELF1
Place a tick in the box for your answer.
YES NO
1. I can identify tools, equipment and testing instruments
2. I can explain the uses and functions of tools, equipment and testing
instruments
40
INTRODUCTION
IDENTIFY AND EXPLAIN OR INTERPRET
THE PRINCIPLES OF OPERATION OF
ELECTRONIC SYMBOLS AND BLOCK
SECTIONS OF SCHEMATIC DIAGRAM
N.C. LEVEL : II
STS
QA
SYSTEM
MAINTAIN AND REPAIR
CELLULAR PHONES
Document No. CES-NC2-CORE-M4-LO3-INTRO
Qualification : Consumer Electronics Servicing NC II
Unit of Competency : Maintain and Repair Cellular Phones
Module Title : Maintaining and Repairing Cellular Phones
Learning Outcome # 3 : Identify and explain or interpret the principles of operation of
electronic symbols and block sections of schematic diagram
Assessment Criteria:
1. Electronic symbols are identified and selected according to the schematic diagram
2. Electronic parts value are read and matched correctly as required
3. Schematic diagram sections and functions are identified and explained
Resources:
Drawing instruments and materials
Working area/bench
Sufficient lighting and ventilation system
Complete electronic supplies
LEARNING EXPERIENCES
Learning Outcome #3: Identify and explain or interpret the principles of operation of electronic
symbols and block sections of schematic diagram
Learning Activities Special Instructions
1. Electronic devices and symbols
2. Resistor Color Code
3. Drawing and Interpreting Schematic
Diagrams
Read Information Sheets 4.3.1
View “Resistor Color Code” CD
Answer Self Check 4.3.1
41
INFORMATION
15
SHEETS 4.3.1
ELECTRONIC DEVICES AND
SYMBOLS
N.C. LEVEL : II
STS
QA
SYSTEM
IDENTIFY AND EXPLAIN OR
INTERPRET THE PRINCIPLES
OF OPERATION OF
ELECTRONIC SYMBOLS AND
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
Objective(s):
Identify electronic devices and symbols
The main components used in electronics are of two general types: passive (e.g. resistors and
capacitors) and active (e.g. transistors and integrated circuits). The main difference between
active
and passive components is that active ones require to be powered in some way to make them
work.
Active components can also be used to amplify signals.
CAPACITOR
COIL (Inductor)
FIXED
VARIABLE
CRYSTAL
DIODE
FUSE
LAMP
42
INFORMATION
SHEETS 4.3.1
SYMBOLS
N.C. LEVEL : II
STS
QA
SYSTEM
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
INTEGRATED CIRCUIT
LIGHT EMITTING DIODE
LOUDSPEAKER
16
METER
MICROPHONE
POTENTIOMETER
QUADRAC
43
INFORMATION
SHEETS 4.3.1
SYMBOLS
N.C. LEVEL : II
STS
QA
SYSTEM
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
RESISTOR
RELAY
SILICON CONTROLLED RECTIFIER (SCR)
THERMISTOR
TRANSFORMER
IF TRANSFORMER
TRANSISTOR
44
INFORMATION
SHEETS 4.3.1
SYMBOLS
N.C. LEVEL : II
STS
QA
SYSTEM
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
FIELD EFFECT TRANSISTOR
MOSFET
UNIJUNCTION TRANSISTOR (UJT)
ZENER DIODE
PHOTOTRANSISTOR
OPTICALLY COUPLED ISOLATOR
45
17
INFORMATION
SHEETS 4.3.1
SYMBOLS
N.C. LEVEL : II
STS
QA
SYSTEM
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
46
INFORMATION
SHEETS 4.3.2
DRAWING AND INTERPRETING
SCHEMATIC DIAGRAMS
N.C. LEVEL : II
STS
QA
SYSTEM
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
Objective(s):
Draw and interpret schematic diagram
ELECTRONIC DIAGRAMS
Ideas in electronics are introduced in diagram form – called SCHEMATIC DIAGRAM.
It shows the components used and their interconnections. Each graphic symbol is also
accompanied with a reference designation to distinguish it from other similar symbols.
The reference designation is the letter and number nearest the graphic symbol. For
example, a section of a circuit is as follows:
The reference designations are R1, Q1, C1 and
SPKR. Their values or actual description are
given in the PARTS LIST like:
R1 – 10 KÙ, ±5%, ¼ watt resistor
Q1 – 9013 NPN audio input transistor(TO-92)
C1 - 470ìF 16 volts electrolytic
SPKR – 8-OHMS 0.5 Watt 2-inch diameter
loudspeaker
47
INFORMATION
18
SHEETS 4.3.2
SCHEMATIC DIAGRAMS
N.C. LEVEL : II
STS
QA
SYSTEM
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
RULES AND CONVENTIONS IN ELECTRONIC DIAGRAMS
Electronic diagrams also follow some rules which are agreed upon by several associations
of electronic engineers.
Among the most common rules are the following:
1. Signal flow in a circuit should be from left
to right of a schematic diagram.
2. Voltage potentials are indicated with the
highest potential placed at the upper
portion of the diagram and the ground
(lowest) potential at the bottom.
3. When interesting lines are to be
connected a small solid circle should be
used.
4. When intersecting lines are not
electrically connected the circuit diagram
is drawn as shown on the left.
The meaning of a symbol does not
change with its position or orientation in a
diagram, its size or line width.
5. Connecting line linking a symbol should
be drawn horizontally or vertically but if
ever a connecting line is drawn at an
angle it implies the same meaning unless
otherwise specified.
6. The standard symbol for a terminal (O)
could be added to any symbol but should
not be considered as part of a symbol.
OTHER COMON PRACTICES
48
INFORMATION
SHEETS 4.3.2
SCHEMATIC DIAGRAMS
N.C. LEVEL : II
STS
QA
SYSTEM
19
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
Interrupted Lines
When a connecting line or group of lines
could not be directly continued to its final
destination, arrows (brackets) with designation
of the destination could be implemented.
Dashed Lines
Dashed lines may be used to indicate an
optionally connected component.
Dashed lines may be used indicate
component content in a single unit.
Dashed lines may be used to indicate
mechanical linkage of two or more components.
49
SELF CHECK
4.3.1
IDENTIFY AND EXPLAIN OR INTERPRET
THE PRINCIPLES OF OPERATION OF
ELECTRONIC SYMBOLS AND BLOCK
SECTIONS OF SCHEMATIC DIAGRAM
N.C. LEVEL : II
STS
QA
SYSTEM
OF OPERATION OF
BLOCK SECTIONS OF
SCHEMATIC DIAGRAM
Document No. CES-NC2-CORE-M4-LO3-SELF1
Place a tick in the box for your answer.
YES NO
1. I can identify electronic symbols
2. I can explain the principles of operation of electronic symbols and
block sections of schematic diagram
3. I can interpret the principles of operation of electronic symbols and
block sections of schematic diagram
50
INTRODUCTION
APPLY SYMPTOMS DIAGNOSIS AND
SYSTEMATIC PRE-TESTING
PROCEDURES
N.C. LEVEL : II
STS
QA
SYSTEM
20
MAINTAIN AND REPAIR
CELLULAR PHONES
Qualification : Consumer Electronics Servicing NC II
Unit of Competency : Maintain and Repair Cellular Phones
Module Title : Maintaining and Repairing Cellular Phones
Learning Outcome # 4 : Apply symptoms diagnosis and systematic pre-testing
procedures
Assessment Criteria:
1. Personal protective equipment are used in accordance with occupational health and safety
practices
2. Control settings/adjustments are checked in conformity with service-manual specifications
3. System defects/Fault symptoms are diagnosed and identified using appropriate tools and
equipment and in accordance with safety procedures
4. Identified defects and faults are explained to the responsible person in accordance with
enterprise or company policy and procedures
5. Customers are advised/informed regarding the status and serviceability of the unit
6. Results of diagnosis and testing are documented accurately and completely within the
specified time
Resources:
TOOLS
Screw driver assorted,
Phillips, slotted
Wrenches assorted
Allen wrench/key
Utility knife/stripper
Pliers assorted, Long
nose, side cutter
Test jig
Set of torx/star bit
Hot air soldering tool
SOFTWARE
N-box
Tornado
Twister
Power flasher
Griffin
EQUIPMENT
Multimeter
Oscilloscope
Function generator
Personal Computer
Bluetooth
Open tool 6600/7650
ESD free work bench with
mirror back-to-back/one
sided
High grade magnifying
glass with lamp
Cell phone unit(s) and
accessories
MATERIALS
Solder lead
21
Cleaning brush
Lead free solder
Resin core solder
Wire stranded, #22,
(different colors)
Silicon grease
Resistors (different
values)
Capacitors (different
values)
Transformer
Learning materials
Books and References
Technical Manuals
Documentation forms
Report forms
51
INTRODUCTION
APPLY SYMPTOMS DIAGNOSIS AND
PROCEDURES
N.C. LEVEL : II
STS
QA
SYSTEM
MAINTAIN AND REPAIR
CELLULAR PHONES
LEARNING EXPERIENCES
Learning Outcome #4: Apply symptoms diagnosis and systematic pre-testing procedures
Learning Activities Special Instructions
1. Principles of Electrical Circuits
2. Electronic circuits
3. Analysis of Troubles
4. Cellular Phone Operations
5. Circuit Board Parts and Functions
View “Ohm’s Law” CD
Answer Self Check 4.4.1
52
INFORMATION
SHEETS 4.4.1
PRINCIPLES OF ELECTRICAL
CIRCUITS
N.C. LEVEL : II
STS
QA
22
SYSTEM
APPLY SYMPTOMS
DIAGNOSIS AND
PROCEDURES
Objectives:
Understand Electrical Circuits
OHM’S LAW
Ohm's law states that the current through a conductor between two points is directly proportional
to
the potential difference or voltage across the two points, and inversely proportional to the
resistance
between them.
The mathematical equation that describes this relationship is:
where I is the current through the resistance in units of amperes, V is the potential difference
measured across the resistance in units of volts, and R is the resistance of the conductor in
units of
ohms. More specifically, Ohm's law states that the R in this relation is constant, independent of
the
current.
Series and parallel circuits
Components of an electrical circuit or electronic circuit can be connected in many different ways.
The two simplest of these are called series and parallel and occur very frequently. Components
connected in series are connected along a single path, so the same current flows through all of
the
components. Components connected in parallel are connected so the same voltage is applied to
each component.
A circuit composed solely of components connected in series is known as a series circuit;
likewise,
one connected completely in parallel is known as a parallel circuit.
53
INFORMATION
SHEETS 4.4.1
CIRCUITS
N.C. LEVEL : II
STS
QA
SYSTEM
APPLY SYMPTOMS
DIAGNOSIS AND
PROCEDURES
In a series circuit, the current through each of the components is the same, and the voltage
across
the components is the sum of the voltages across each component. In a parallel circuit, the
voltage
across each of the components is the same, and the total current is the sum of the currents
through
23
each component.
As an example, consider a very simple circuit consisting of four light bulbs and one 6 V battery.
If a
wire joins the battery to one bulb, to the next bulb, to the next bulb, to the next bulb, then back to
the
battery, in one continuous loop, the bulbs are said to be in series. If each bulb is wired to the
battery
in a separate loop, the bulbs are said to be in parallel. If the four light bulbs are connected in
series,
the same current flows through all of them, and the voltage drop is 1.5 V across each bulb and
that
may not be sufficient to make them glow. If the light bulbs are connected in parallel, the current
flowing through the light bulbs combine to form the current flowing in the battery, while the
voltage
drop is 6.0 V across each bulb and they all glow.
In a series circuit, every device must function for the circuit to be complete. One bulb burning out
in
a series circuit breaks the circuit. In parallel circuits, each light has its own circuit, so all but one
light
could be burned out, and the last one will still function.
Series circuits
Series circuits are sometimes called current-coupled or daisy chain-coupled. The current that
flows
in a series circuit will flow through every component in the circuit. Therefore, all of the
components
in a series connection carry the same current.
Resistors
Inductors
Capacitors
The working voltage of a series combination of identical capacitors is equal to the sum of
voltage
ratings of individual capacitors. This simple relationship only applies if the voltage ratings are
equal
54
INFORMATION
SHEETS 4.4.1
CIRCUITS
N.C. LEVEL : II
STS
QA
SYSTEM
APPLY SYMPTOMS
DIAGNOSIS AND
PROCEDURES
as well as the capacitances. However, the division of DC voltage between the capacitors is
dominated by the leakage resistance of the capacitors, rather than their capacitances, and this
has
considerable variation. To counter this equalising resistors may be placed in parallel with each
capacitor which effectively add to the leakage current. The value of resistor chosen (perhaps a
few
24
megohms) is as large as possible, but low enough to ensure that the capacitor leakage current
is
insignificant compared to the current through the resistor. At DC, the circuit appears as a chain
of
series identical resistors and equal voltage division between the capacitors is ensured. In
highvoltage
circuits, the resistors serve an additional function as bleeder resistors.
Switches
Two or more switches in series form a logical AND; the circuit only carries current if all switches
are
'on'. See AND gate.
Cells and batteries
A battery is a collection of electrochemical cells. If the cells are connected in series, the voltage
of
the battery will be the sum of the cell voltages. For example, a 12 volt car battery contains six 2-
volt
cells connected in series.
Parallel circuits
If two or more components are connected in parallel they have the same potential difference
(voltage) across their ends. The potential differences across the components are the same in
magnitude, and they also have identical polarities. The same voltage is applicable to all circuit
components connected in parallel. The total current I is the sum of the currents through the
individual components, in accordance with Kirchhoff’s current law.
Resistors
The current in each individual resistor is found by Ohm's law. Factoring out the voltage gives
To find the total resistance of all components, add the reciprocals of the resistances Ri of each
component and take the reciprocal of the sum. Total resistance will always be less than the
value of
the smallest resistance:
55
INFORMATION
SHEETS 4.4.1
CIRCUITS
N.C. LEVEL : II
STS
QA
SYSTEM
APPLY SYMPTOMS
DIAGNOSIS AND
PROCEDURES
For only two resistors, the unreciprocated expression is reasonably simple:
This sometimes goes by the mnemonic "product over sum".
For N equal resistors in parallel, the reciprocal sum expression simplifies to:
and therefore to:
To find the current in a component with resistance Ri, use Ohm's law again:
The components divide the current according to their reciprocal resistances, so, in the case of
two
resistors,
An old term for devices connected in parallel is multiple, such as a multiple connection for arc
lamps.
Inductors
25
Inductors follow the same law, in that the total inductance of non-coupled inductors in parallel is
equal to the reciprocal of the sum of the reciprocals of their individual inductances:
56
INFORMATION
SHEETS 4.4.1
CIRCUITS
N.C. LEVEL : II
STS
QA
SYSTEM
APPLY SYMPTOMS
DIAGNOSIS AND
PROCEDURES
Capacitors
Capacitors follow the same law using the reciprocals. The total capacitance of capacitors in
parallel
is equal to the sum of their individual capacitances:
.
The working voltage of a parallel combination of capacitors is always limited by the smallest
working
voltage of an individual capacitor.
Switches
Two or more switches in parallel, form a logical OR; the circuit carries current if at least one
switch
is 'on'. See OR gate.
Cells and batteries
If the cells of a battery are connected in parallel, the battery voltage will be the same as the cell
voltage but the current supplied by each cell will be a fraction of the total current. For example, if
a
battery contains four cells connected in parallel and delivers a current of 1 ampere, the current
supplied by each cell will be 0.25 ampere. Parallel-connected batteries were widely used to
power
the valve filaments in portable radios but they are now rare.
DC Circuits
A DC circuit (Direct Current circuit) is an electrical circuit that consists of any combination of
constant voltage sources, constant current sources, and resistors. In this case, the circuit
voltages
and currents are constant, i.e., independent of time.
In electronics, it is common to refer to a circuit that is powered by a DC voltage source such as a
battery or the output of a DC power supply as a DC circuit even though what is meant is that the
circuit is DC powered.
AC Circuits
In alternating current (AC) the movement of electric charge periodically reverses direction. In
direct
current (DC), the flow of electric charge is only in one direction.
AC is the form in which electric power is delivered to businesses and residences. The usual
waveform of an AC power circuit is a sine wave. In certain applications, different waveforms are
used, such as triangular or square waves. Audio and radio signals carried on electrical wires are
also examples of alternating current. In these applications, an important goal is often the
recovery of
information encoded (or modulated) onto the AC signal.
26
57
INFORMATION
SHEETS 4.4.2 ELECTRONIC CIRCUITS N.C. LEVEL : II
STS
QA
SYSTEM
APPLY SYMPTOMS
DIAGNOSIS AND
PROCEDURES
Objectives:
Understand electronic circuits and components
Electronic circuit
An electronic circuit is composed of individual electronic components, such as resistors,
transistors,
capacitors, inductors and diodes, connected by conductive wires or traces through which electric
current can flow. The combination of components and wires allows various simple and complex
operations to be performed: signals can be amplified, computations can be performed, and data
can
be moved from one place to another. Circuits can be constructed of discrete components
connected
by individual pieces of wire, but today it is much more common to create interconnections by
photolithographic techniques on a laminated substrate (a printed circuit board or PCB) and
solder
the components to these interconnections to create a finished circuit. In an Integrated Circuit or
IC,
the components and interconnections are formed on the same substrate, typically a
semiconductor
such as silicon or (less commonly) gallium arsenide.
Breadboards, perfboards or stripboards are common for testing new designs. They allow the
designer to make quick changes to the circuit during development.
An electronic circuit can usually be categorized as an analog circuit, a digital circuit or a
mixedsignal
circuit (a combination of analog circuits and digital circuits).
A circuit built on a printed circuit board (PCB)
Analog circuits
Analog electronic circuits are those in which current or voltage may vary continuously with time
to
correspond to the information being represented. Analog circuitry is constructed from two
fundamental building blocks: series and parallel circuits. In a series circuit, the same current
passes
through a series of components. A string of Christmas lights is a good example of a series
circuit: if
one goes out, they all do. In a parallel circuit, all the components are connected to the same
voltage, and the current divides between the various components according
27

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