Brief Description Of Laptop Repair

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.