The Good Repaired Method for PCB board
In recent years, the degree of automation of industrial equipment is getting higher and higher, so the number of industrial control boards in various industries is increasing. After the industrial control board is damaged, the high cost of replacing the circuit board (less than a few thousand dollars, more than Ten thousand or several hundred thousand yuan has also become a very headache for companies. As an emerging repair industry, circuit board repair is also growing rapidly. The vast majority of damaged boards are repairable in the country, and they save 70% - 80% of the cost of buying a new board, and the time spent is much shorter than the time of foreign board. The following describes the basics of circuit board maintenance.
Almost all boards are repaired without drawing materials, so many people are skeptical about board maintenance. Although the various boards vary widely, the same is true for each board, which consists of various integrated blocks, resistors, capacitors, and Other devices are formed, so board damage must be caused by damage to one or some of the devices. The idea of board repair is based on the above factors. Circuit board maintenance is divided into two parts: inspection and maintenance, in which the inspection occupies a very important position. A basic knowledge of each device on the board is tested until a bad part is found and replaced, and then a board is repaired.
Board inspection is the process of finding, determining, and correcting every electronic component failure on a board. In fact, the whole testing process is a thinking process and a testing process that provides logical reasoning clues. Therefore, the testing engineer must gradually accumulate experience and continuously improve the level during the maintenance, testing, and maintenance of the circuit board.
The general electronic equipment is composed of thousands of components. In the maintenance and overhaul, if you directly check each component in the circuit board to find the problem, it will be very time-consuming and very implementation-oriented. difficult. Then, from the fault phenomenon to the fault-caused check-in type, it is an important maintenance method. As long as the board detects the problem, the repair is easy. The following is a summary of the basic maintenance of the circuit board, which is convenient and practical.
A common circuit board, the circuit is combined into millions
Component appearance changes frequently, and character recognition is the key
Resistor capacitors are the most common and damage is common
The resistance value is easy to change, and the capacitor leakage is still leaking.
Inductor transformer is a coil, simple test to see on and off
Diodes and triodes, measuring the PN junction positive and negative
MOS tube and thyristor, trigger test is the key
All of the above are discrete pieces, integrated circuits for many years
Analog devices have op amps, virtual short and virtual ends to judge
Optocoupler isolation front and rear stages, damage is tens of millions
Digital devices are often seen, 40 and 74 front
There are also analog-to-digital converters, which are very laborious to test.
Don't forget ROM and CPLD, programming depends on the programmer
CPU, single chip, timing judgment logic
A variety of sensors, the probability of damage is ranked first