Laptop computers are mobile office
computers developed after desktop computers. They have the characteristics of low power
consumption and convenient mobility. They have completely replaced
desktop computers in some occasions. Laptop computer repair can basically
be divided into four levels according to the depth of repair.
1. Application level maintenance
Application-level maintenance mainly
refers to the repair of faults caused by the laptop's operating system and
application software. Common ones include installing the operating system,
graphics card, sound card, network
card and other hardware drivers,
upgrading the BIOS, etc. This level of maintenance is low-difficulty. Anyone with a certain
knowledge of computer usage can quickly get started and master maintenance
skills. Most computer users can also acquire such skills through self-study.
Therefore, there are very few people learning application-level maintenance.
2.
Board level maintenance
Board-level maintenance mainly refers
to the replacement and maintenance of related hardware faults, such as fault
detection and manual replacement of CPU, memory, hard disk, LCD screen, and
battery. Since laptops are highly
integrated designs, they are difficult to disassemble and assemble, and you
need to master some basic electronic knowledge
when performing this level of maintenance, such as measuring
voltage and resistance.
Therefore, learning board-level maintenance has relatively high requirements for hands-on ability.
3.
Chip level repair
The chip-level maintenance mentioned
in this book is to use multimeters, oscilloscopes, maintenance power supplies,
air guns and soldering irons and other equipment to repair laptop motherboards
by replacing components, such as power
supply field effect
transistors, switching power
supply ICs, etc. Chip-
level maintenance requires certain electronic theoretical knowledge and
relatively strong hands-on ability, and the ability to analyze circuit
diagrams, and then combine the measurement results of various instruments to judge short circuits, open circuits, etc. inside the components, and based on This will replace
the components and complete the repair.
4.
Signal level repair
Signal-level maintenance is an
advanced process of chip-level maintenance and is currently the highest level of maintenance. It requires
the repairer to be very familiar with the circuit and be able to skillfully
understand the circuit diagram and analyze the principle of the circuit.
Compared with chip-level maintenance, signal-level maintenance focuses more on
the measurement of key signals in the circuit. Generally, an oscilloscope is used to capture and
compare the signals to locate the fault at the bus level or a small resistor
around the component. or on the capacitor. Signal level maintenance is the most
in-depth maintenance method. The actual maintenance of a laptop should be chip
level + signal level maintenance. It
is necessary to determine which components on the motherboard are broken and
the conditions required for the chip to work. Currently, the market for
chip-level maintenance personnel is still in short supply, and training
institutions in this area are only available in first-tier cities.
Basics required
for laptop repair
A truly qualified laptop repair
engineer needs to have a solid foundation in electronic theory, proficient hands-on skills, and careful
thinking, so as to ensure the successful repair of every faulty laptop.
As a laptop maintenance engineer, you
must not only have a comprehensive understanding of the hardware, software and
structure of laptops, but also master certain basic maintenance knowledge.
1.
Have basic knowledge of electronic circuits
Laptop computer maintenance personnel
must master the basic knowledge of analog and digital circuits and understand
some basic concepts in circuits, such as short circuit, open circuit, etc.
For the electronic theoretical basis
of laptop computer repair, there are two concepts that must be clear, namely "signal" and
"timing". "Signal" refers to the data and instructions sent
by the laptop motherboard to various circuit parts on the motherboard when it
is working. Signals are the most basic element
for laptops to work. As the name suggests, "timing" refers to the time and sequence, which refers
to the interval and sequence of signals sent and
received by various circuits of the motherboard from startup to normal operation of the laptop motherboard. The
timing is strict and cannot be changed. If the timing If an error occurs, it
may cause the laptop motherboard to be unable to power on, unable to boot, and other unknown failures. Although there are many brands of laptops,
no matter what kind of laptop they are, they all use Intel or AMD platform
chipsets, and the same chipsets basically use the same timing. Therefore, if
you are proficient in timing and signals, you will no longer have the feeling
of not knowing where to start when repairing a laptop. Faced with various
faults, you can perform corresponding repairs and analysis according to the corresponding
timing. This book focuses on the most critical "signals" and
"timing" and guides beginners to correctly learn laptop repair
technology from the shallower to the deeper.
2.
Master the relevant knowledge of electronic components
Laptops, like other electronic
products, are also composed of electronic components and integrated circuits
(except that due to their small size, the electronic components used in laptops
are all chip components). When repairing laptop computers, maintenance
personnel must have a certain understanding of the characteristics and
functions of common components such as resistors, capacitors, inductors, and
semiconductor diodes, transistors, field effect transistors, crystal
oscillators, and gate circuits, and be able to
identify and judge different electronic components. good or bad.
3.
Understand the structure of a laptop
It is necessary to understand the
structural composition of the laptop and the distribution of its components,
clarify the working characteristics of the laptop, be familiar with the
disassembly process and maintenance steps of the laptop, and master the
functional characteristics and prone failures of the laptop's components.
4.
Have hands-on skills and safety
awareness
You need to understand the functions,
features and usage of soldering irons, heat guns, diagnostic cards, regulated
power supplies, multimeters, oscilloscopes, and BGA rework stations. Laptop
computer maintenance personnel are required to have good hands-on skills and be
able to use tools and instruments correctly during the maintenance process.
Although there is no danger of high voltage in the current new laptop
computers, the circuits are all large-scale integrated circuits. The internal
insulation layer of large- scale integrated circuits is thin, the connection
spacing is small, and the breakdown voltage is low, making its anti-static
ability very weak. Therefore, in addition to taking anti-static measures in the
maintenance environment, maintenance personnel must also take anti-static
measures to avoid damage to maintenance equipment caused by static electricity
carried by the human body.
Characteristics of laptop computer
failures and current status of
repair market
Due to strict requirements for mobile
use, notebook computers have the following design characteristics compared with
desktop computers:
(1) Small
size. Today's laptops are developing towards thinness and lightness. For
example, Apple's MacBook Air 11-inch laptop weighs only about 1kg, so all parts
of the laptop, such as the motherboard, casing, screen, etc., adopt lightweight
designs.
(2) Energy
saving. The trend of notebook computer use is high battery life, because many
users use notebook computers when going out, and there is no guarantee that
power will be available at all times. However, there are no major breakthroughs
in battery technology today, so we can only use energy saving. To carry out
design, we have chipsets, CPUs, etc. for mobile platforms from companies such
as Intel. On the premise of ensuring performance, power consumption is reduced
so that users can use it longer.
(3) High
integration. Compared with desktop computers, laptops use a smaller size to
complete the same work. Users
cannot accept using
a laptop while
connecting various external
devices, so a small laptop must integrate many devices.
Function. In terms of design, the motherboard of a laptop computer must carry a
variety of devices, so the circuit and structure of the laptop computer are
much more complex than that of a desktop computer.
In terms of environment and usage
habits, laptops are generally used in casual environments, such as in cars,
trains, restaurants, beds, sofas, etc. Frequent use of laptops on the sofa or
bed will cause poor heat dissipation of the laptop, which can easily lead to
laptop crashes and other malfunctions; some people surf the Internet while
drinking, which can easily cause water to enter the laptop; often holding the
laptop with one hand Walking around, the notebook computer is prone to uneven
stress, causing the BGA chip of the motherboard to be soldered empty.
With the rapid development of the
laptop sales market, the laptop repair industry has also entered a blowout stage.
There are more and more merchants engaged
in the laptop repair industry
in major computer markets. Generally, there are
two types of laptop repair merchants, one is an officially authorized repair
center, and the other is a repair merchant. In fact, most of the official maintenance centers can only perform
the application-level and board-level maintenance mentioned in Section 1.1.
Maintenance merchants can perform four levels of maintenance, but due to
Differences in skills and abilities among employees, coupled with the lack of unified standards in the entire
industry, have also resulted in uneven quality of repair businesses, and a wide
disparity in laptop repair capabilities.
Many unprofessional repair merchants
only have a few simple tools and a small counter. They do not have
oscilloscopes, BGA desoldering stations and other professional equipment
required for repair, and they do not have a deep understanding of laptop repair technology. With so few simple detection
methods, I know very little
about the working timing and signal functions of the laptop motherboard. Some
even cannot understand the circuit diagram, so I can only detect some simple
faults or "common faults". When
it comes to maintenance, if you encounter a slightly more complicated fault,
you will be at your wits end.
However, laptops will have a variety
of faults, and the fault may not be determined by replacement like a desktop
computer (most laptops have integrated graphics cards, and some laptops with
thin and light designs even have their CPU, memory They will all be integrated
on the motherboard, and the price of the motherboard is relatively high, so it
is not realistic to buy it and replace it). Therefore, 90% of laptop computer failures
require laptop motherboard repair. However, the current repair market is a mixed bag.
Many "engineers" who have no electronic
foundation and hands-on ability are engaged in laptop repair business. The author once joked that many
maintenance personnel Like Cheng Yaojin
in "The Romance of the Sui and Tang
Dynasties", he only has the "three axes" to take care of his
house, that is, flash the BIOS, change the EC, and change the north and south
bridges. If the problem cannot be solved, he has to throw it aside and become a
"rigid" one, or Only a new motherboard can be replaced and delivered
to the customer. This kind of extensive and haphazard maintenance has led to
the death of many faulty machines that could have been easily repaired. There
are also many maintenance personnel who are not proficient in using the most
basic tools - air guns and soldering irons. Welding in space and time,
soldering, tin connection, etc. are very common, causing simple faults to be
artificially amplified twice, and this kind of human faults It's very difficult
to deal with.
