1. Change directly on behalf of

     Direct replacement refers to the use of other IC chips directly to replace the original IC without any changes. After the replacement, it does not affect the main performance and indicators of the machine.

     The principle of replacement is: the functions, performance indicators, packaging forms, pins, pins serial numbers and interval are the same. Among them, the function of ICs not only refers to the same functions, but also pay attention to the same logic polarity, that is, the output input level polarity, voltage, and current range must be the same. Performance indicators refer to parameters such as IC's main electro -parameter (or main characteristic curve), maximum dispersal power, maximum working voltage, frequency range, and signal input, output impedance, etc. are similar to the original IC. Small power substitutes should be increased.

     1. The replacement of the same model IC chip

     The replacement of the same type of IC chip is generally reliable. When installing integrated PCB circuits, pay attention not to make the direction. Otherwise, integrated PCB circuits during power are likely to be burned. Some single -column direct -inserted amplifier ICs, although the models, functions, and characteristics are the same, the direction of the order of pins is different. For example, the dual -channel amplifier ICLA4507, the pin is divided into "positive" and "anti", the starting foot label (color point or pit) direction is different: no suffix and suffix are "R", IC, etc., such as the IC, etc., such as the IC, etc., such as the IC, etc., such as the IC, etc. M5115p and M5115RP.

     2. The replacement of different model ICs

     (1) The exchanges of the models of the model and different ICs. As long as the pins function of each other is exactly the same, the internal PCB circuit and electrical parameters are slightly different, and they can also be replaced directly on behalf of each other. For example, the IC LA1363 and LA1365 are placed in the pronunciation, and the latter adds a stabilization diode to the inside of the former. The other is exactly the same.

     (2) The replacement of different types of prefixes and the same IC. Under normal circumstances, prefix letters are the category of manufacturers and PCB circuits. The number behind the prefix letters is the same, and most of them can be replaced directly. But the number, although the number is the same, the function is completely different. For example, HA1364 is a pronunciation IC, and UPC1364 is a color decoding IC; 4558, 8 -pin is the operational amplifier NJM4558, and the 14 -foot is CD4558 digital PCB circuit; therefore, the two cannot be replaced.

     (3) Model prefix letters and numbers are different from IC. Some manufacturers introduce an unpackaged IC chip, and then processed into products named by the factory. Also, improve the product as in order to improve certain parameter indicators. These products are commonly used for names or model suffixes. For example, AN380 and UPC1380 can be replaced directly; AN5620, TEA5620, DG5620, etc. can be changed directly.

     Second, non -direct replacement

     Non -direct replacement means that the IC that cannot be directly replaced can be modified slightly to modify the PCB circuit to change the arrangement of the original pins or increase or decrease individual components to make it a replaceable IC method.

     Principles of replacement: ICs used for replacement can be different from the original IC pin function and different shapes, but the function should be the same and the characteristics should be similar; after the replacement, it should not affect the performance of the original machine.

     1. The same but different pins function of different IC chips

     This replacement needs to change the arrangement of the PCB circuit and foot pins, so it requires certain theoretical knowledge, complete information and rich practical experience and skills.

     2. The PCB circuit has the same function, but the replacement of the LC chip is different in individual pin functions

     When replacing the specific parameters and descriptions of each model IC. For example, the difference between AGC and video signal output in the TV is different and negative. As long as the output end is added to the phase, it can be replaced.

     3. Some empty feet should not be ground without authorization

     Some internal equivalent PCB circuits and application PCB circuits are not indicated. When the air leading feet are encountered, they should not be grounded without permission. These leading feet are replaced or spare feet, and sometimes as internal connections.