1. It is necessary to have a picture of the chest

To thoroughly understand the principles of some typical circuits, familiar with the heart. The drawing is dead, and the thought in the head is alive. It can be analogized, can be reasoned, can draw inferences from one instance, and have all kinds of connections. For example, switching power supply, always inseparable from the oscillation circuit, switch tube, switch transformer these, check whether the circuit has vibration, whether the capacitor is damaged, whether the triode, diode is damaged, no matter what switching power supply is encountered, the operation is almost the same, there is no need to force circuit diagram; for example, single-chip microcomputer system, including crystal oscillator, three bus (address line, data line) In addition, there are also various types of input and output circuits, such as analog circuits and analog circuits. After practicing the good skill of analysis and reasoning, even if you encounter equipment that you have never seen before, you just need to understand the principle.

2. Pay attention to the maintenance sequence

Only by paying attention to the maintenance sequence can we find the shortest path to solve the problem, so as to avoid random poking and dismantling, and failure of maintenance will lead to the expansion of fault. Maintenance is like a doctor giving medical treatment, but also pay attention to a “look, hear, ask”. “Look” means to check the appearance of the fault board to see if there are obvious damage marks on it, whether the components are burnt black or cracked, whether the circuit board has broken wires and electric leakage caused by corrosion, whether the capacitor has liquid leakage, whether the top has bulged, etc; “Sniff” is to sniff whether something is burnt with the nose, and where the smell comes from; “ask” is very important. It is necessary to ask the party in detail about the situation of the equipment failure, and infer the possible fault parts or components from the situation; “cut” means using certain detection instruments and means to check the resistance value of circuit parts or components in two cases of power on and off Compare the good and bad circuit boards and observe the difference of parameters.In fact, there are a lot of problems that you can solve without using a multimeter, so the circuit diagram will be avoided.

3. Be good at general rules.

Generally, after accumulating certain maintenance experience, you should be good at analyzing the causes of each component damage, such as improper operation? Lack of maintenance? Unreasonable design? Poor quality of components? Natural aging? With these analyses, the next time you encounter the same kind of fault, even if it is not the same circuit board, you will have a bit of bottom. For example, I once encountered a Cincinnati machining center that broke down from time to time. The supplier replaced the software to reduce harmonic interference, so as to remove all the boards and reproduce the fault on other good machines. After a month of dismantling, the problem was not solved. Because I have repaired a lot of computer motherboard faults, and found that many of them are good and bad. There are many problems with the capacitance on the motherboard of the year. I think this is the same for the control board of the machining center. So I replaced all the capacitors on the board, and the problem was solved in only one hour.

4. Be good at finding information

Since the advent of the Internet, it has become very easy to find information. The principle of equipment and circuit can be found on the Internet, and any IC information can be found on the Internet. In the past, it was said that the master led the apprentice, but whether the apprentice could learn well depends on whether the master has the heart to lead. Now you don’t have to. With the Internet, your masters are all over the world. There are all kinds of masters. Of course, if you don’t have a high degree, English is a gap in front of us. Many things can be understood only with English foundation. For example, many IC materials are in English. But with Jinshan Ciba, you have this professional foundation, and you can understand many things even if you guess them. With useful information, no picture is the same as having a picture. It’s no big deal.

5. Necessary testing equipment shall be provided

If you take maintenance as your own business, then a certain amount of equipment investment is necessary. Electric soldering iron, multimeter, commonly used disassembly tools, etc. If possible, make a 100m dual trace oscilloscope, and if possible, set up an on-line maintenance tester.