1. To "have a solid picture"

It is necessary to thoroughly understand the principles of some typical circuits and be familiar with them. The drawings are dead, and the thoughts in the head are alive. They can be analogized, reasoned, and inferred. For example, the switching power supply is always inseparable from the oscillating circuit, switching tube, and switching transformer. During the inspection, check whether the circuit is vibrated, whether the capacitor is damaged, whether the transistors and diodes are damaged, and no matter what switching power supply is touched, it can be operated. They are almost the same, do not have to force a circuit diagram; for example, a single-chip microcomputer system, including crystal oscillator, three buses (address line, data line, control line), input and output interface chips, etc., are also inseparable from these ranges for maintenance; another example is various operational amplifiers The composed analog circuit, despite its numerous changes, is inferred on the basis of "virtual shortness" and "virtual disconnection". After practicing good analysis and reasoning skills, even if you encounter a device you have never seen before, you only need to understand the principle.

2. Pay attention to the order of maintenance

Dongguan circuit board repair manufacturers introduced that they must pay attention to the maintenance sequence to find the shortest path to solve the problem, avoid chaotic disassembly, failure to repair, and cause the failure to expand. Maintenance is like a doctor's treatment, but also pay attention to "seeing, hearing and asking." "Hope" is to check the appearance of the faulty board to see if there are any obvious signs of damage on it, if there are components burned black or cracked, if the circuit board is broken or leaked due to corrosion, if there is any leakage of capacitors, and if there is any drum on the top. Wait; "sniff" with your nose to see if there is a burning smell, where did the smell come from; "ask" is very important, you must ask the person in detail about the situation at the time when the equipment fails, and you can reason from the situation To check the resistance, voltage, waveform, etc. of the circuit part or component, and to compare the good and bad circuit boards and observe Differences in parameters, etc.

In fact, there are many faults that you can solve without even using the multimeter, and the circuit diagram is naturally avoided.

3. To be good at general rules.

Generally, after a certain amount of maintenance experience is accumulated, you should be good at analyzing the cause of each component damage in the main section. It is improper operation, lack of maintenance, unreasonable design, poor quality of components, and natural aging. With these analyses, you will encounter it next time. Similar faults, even though they are not the same circuit board, have a bit of insight in my heart. For example, I once encountered a failure of a Cincinnati machining center from time to time. The supplier adopted methods such as reinstalling the software to reduce harmonic interference, and even removing all the boards to reproduce the failure on other good machines. After a month of dismantling, the problem was not solved in the end. Because I have repaired a lot of computer motherboard failures, and found that many of them are good and bad. The capacitors on the motherboards that have been used for the years are problematic. I think this is the same for the control board of the processing center, so I changed the capacitors on the board. Replaced them all, and the problem was solved in only an hour.

4. Be good at finding information

Since the advent of the Internet, finding information has become very easy. Almost all the device principles and circuit principles that you don't understand can be found on the Internet, and any IC information can be found on the Internet. In the past, it was taught that the master leads the apprentice, but whether the apprentice learns well depends on whether the master has the heart to teach him. No need now. With the Internet, your masters are all over the world, and there are any kind of masters. Of course, if you are not well-educated, English is a ditch in front of us. Many things need to be understood in English. For example, many IC materials are in English. But with Kingsoft PowerWord, you have this professional foundation, and a lot of things can be understood even if you guess it. With useful information, no picture is the same as there is a picture, it's no big deal.