¿How
does this system?
We developed a series of chapters
in which you can learn everything you need to initiate in this exciting field
of Mobile Telephony.
This course requires no prerequisites
as our program aims at a system from ZERO, will explain everything you need to
know before proceeding to disassemble the first phone.
Only require the willingness
to learn and invest a little time for it.
And if you already have experience
in this, you can expand your knowledge and to develop different TIPs from the
simplest to the most complex of a failure.
No more time to waste, let's
start the course now!
What tools do I need to initiate?
The tools are divided into two groups, those necessary to repair
the hardware and the tools needed for repairs at the software level.
For repair at the hardware
level:
Set precision screwdriver Set precision torx set Soldering iron Hot air gun soldering Flux soldaring past Isopropyl alcohol Digital multimeter Cuter Soft bristle paint brush Pencil eraser Tweezer for electronics Magnifying glass Adjustable DC power supply
¡IMPORTANT!
In this course we
develop everything related to repairs at the hardware level and make an
introduction to repairs at the software level, since for repairs at the
software level is necessary a prerequisite as being the proper handling of computer
tools.
For repairs to level software:
PC or Notebook Flash Box, there are many differents makes/models
of the cell phones. USB data cable for differents models
of cell phones 
Security measure for our work table.
Counting on the electrical system grounded in
the work table Anti static wristband. Anti static mat Anti static drawer.
Anti static accessories:
How does a cell phone?
The first thing to know is, how
a Cell Phone, and nothing would better understand its operation through block
diagrams, a cell phone is fully represent three main blocks.
Block RF Block AF Logical area
Block RF (radio frecuency)
It is divided into two block RX
(receive) and TX (transmit).
This block is responsible for the entire signal
processing, both signal incoming and outgoing phone.
The RF signal enters through the
antenna to the RF receiver circuit, that is where demodulates the signal and filtering
is done where there is the F.I. signal (intermediate frecuency) will be sent to
the module AF (audio frequency) output to your speakers will give us voice (audio).
Block AF (audio frecuency)
Is the block is responsible for the
conversion of F.I. (MF) from the RF block, specifically the block RX in RF, and
is responsible for converting this signal into voice through the speaker output.
In turn is responsible for processing the incoming audio to the phone from the MIC
to submit TX block are and is transmitted. In summary, this area is responsible
for processing the audio cell phone.
Logical área
It is the area that is responsible for processing all data input and output,
and is similar in operation to a PC, find logical area within the
microprocessor, the memories: RAM, EEPROM or Flash memory, input devices and output
data, display, keyboard, etc..
The microprocessor is who maintains total control telephone, but based on data / instruction loaded into the phone memory, the data / instructions form what is known as operating system, there is written everything the phone can do.
The microprocessor is who maintains total control telephone, but based on data / instruction loaded into the phone memory, the data / instructions form what is known as operating system, there is written everything the phone can do.
Conclusions:
Why should we know that these blocks perform basic
functions of cell phone?
Understand the operation through block diagrams allow
us to point out flaws because, depending on the type, know that corresponds phone
area, which results in better diagnosis leading toward the success of our
repairs.
¡IMPORTANT!
In later chapters we will be showing how to identify these areas in different plates cell phones.
In later chapters we will be showing how to identify these areas in different plates cell phones.
For example:
If you have problems making calls with a cell phone, and shows us onscreen System Busy or give us falling fast busy or calls, we have to check the phone's RF area, specifically TX RF as RF handles the processing specifically TX signals and handles the phone's outgoing signal, be expanded detail in later chapters.
If you have problems making calls with a cell phone, and shows us onscreen System Busy or give us falling fast busy or calls, we have to check the phone's RF area, specifically TX RF as RF handles the processing specifically TX signals and handles the phone's outgoing signal, be expanded detail in later chapters.
Blocks Cell Phone – Typical Problems
In the following chart are
indicated the main blocks of a cell phone and the faults common to be found on
every block, in later chapters are indicating how to locate these blocks on the
boards of different brands / models of phones.
Conditions for a properly functioning cell phone.
1. The operating frequency of the operator must be
consistent with the operating frequency of the cellular telephone
2. The cell phone must have no SIM Lock with SIM Card to
use
3. The electronic serial number of your phone (IMEI), must
not be negative band
4.
Configure multimedia services
The operating frequency of the operator must be consistent with the
operating frequency of the cellular telephone
In GSM there are the following
operating frequencies: 850, 900, 1800 and 1900 MHz, which means that, if the
frequency of operation of an operator, for example, is 850 Mhz and want to use a
phone that does not support this frequency, for example, a European series phone
that only works in the range of 900, 1800, 1900 Mhz, the cell phone will not
work, ie you can not sign up for not being in tune with the frequency of the
operator.
Example.
“It's like
trying to listen to the radio to a station that transmits at 100.9 MHz with a
radio tuned to another frequency, could not listen to the station for not being
in tune.”
NO cell phone must have SIM Lock
with SIM Card to use.
It means that the cell phone should
not be blocking for the SIM Card to use, as certain operators lock their phones
so that only functions with your SIM Card.
Electronic Serial Number of
the phone (IMEI) should not be negative band.
The serial number (IMEI)
should not be reported as the terminals send information to register phone IMEI
and if the operator is in the database of reported series in the EIR, send commands
restriction line and may not use the equipment.
Configure Multimedia Services
1.
Internet access
2. Sending MMS (Multimedia
Messaging)
¡IMPORTANT!
If we have problems
with a cell phone, first must verify the conditions for proper operation, and if
they meet all the conditions, he would be facing a cellphone with a desperfecto.2.
Sending MMS (Multimedia Messaging).
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