circuit board maintenance is divided into maintenance with diagram and maintenance without diagram.
The maintenance method with diagram is to refer to the schematIC diagram, analyze the circuit principle and signal trend, and then test the signals on the key points. In this case, it is easy to repair the circuit, but many industrial control boards have no schematic diagram, and the circuit board manufacturers will not give it to general users as a secret.
Professional maintenance company, almost all circuit boards are repaired without drawings. I will exchange my experience in repairing circuit boards without drawings with you in recent years, and I hope you can give me some advice.
A circuit board is composed of circuit boards, components and software. In my opinion, the ability of maintenance personnel and inspection tools are very important when repairing circuit boards. It is difficult to maintain modern circuit boards only by relying on one's experience without necessary tools, and it is also difficult to advocate online testers and other testing equipment without paying attention to personnel quality.
The way to deal with the boards you are facing during maintenance is different. But the basic idea is to find out the bad components and replace and repair them. Can we just replace all the replaceable components on the board? I have tried to replace it, but it is not good. Some components need to be debugged. Pay attention to the overall effect.
Use online tester and other tools like mine sweeper, MARK each component and check it once, and compare the VI curve. In this way, some faults can be found, but not all of them can be repaired. "Because the chips passed the online tester are not necessarily damaged; the chips passed the test are not necessarily undamaged." Not every component can be found in the component library. The machine tool circuit board is constantly updated, so your detection tools are also constantly updated.
The quality of the maintenance personnel directly affects the success or failure of the maintenance. In the absence of any schematic diagram, it is necessary to repair a relatively unfamiliar circuit board. In addition to the profound hardware skills, the maintenance engineer who also needs to have a good understanding of the circuit principle and structure should carefully observe the hardware structure to determine the role of the board, and ask the customer what kind of alarm was reported when the board was instalLED on what machine tool.
When judging the function of a circuit board, it is necessary to construct the block diagram of the secondary circuit board in mind. From the analysis of the alarm information, which link is faulty, and which components may be faulty, and then test after replacement. If you want to ask, since the maintenance personnel are so good, they still have to repair here instead of designing? In fact, design and maintenance are all about making money. Our treatment of maintenance personnel is not inferior to that of design personnel. Besides, maintenance is more challenging. I like the feeling that you find problems and fix them when you face different things every day.
During maintenance, the method of the staff is also very important. Circuit board repair is a very delicate job. There are many components and circuit boards that are easy to be damaged. Therefore, the operation should be very careful and requires necessary auxiliary tools such as clamps. DiSMAntling, welding, etc. shall be skilled. Before starting, the whole operation process shall be planned to avoid unnecessary damage. For chips with programs, try to back up those that can be backed up, and never move those that cannot be backed up. If it is found that the chip with program is damaged, and no spare or replacement chip can be found, then the circuit board cannot be repaired.
The detection of circuit boards and components requires professional detection tools, such as whether there is broken wire in multi-layer circuit boards and whether there is faulty soldering in components.
In addition to finding the bad things to repair, the most difficult thing for maintenance is to check whether they are repaired and debugged on the computer. No matter how you repair them, they should finally be installed on the machine tool and the circuit boards sent to the customer must be good. This requires testing on the computer before they are sent out. Our company has purchased a large number of maintenance experimental test benches and made tests based on the SIMulation of the customer's boards, To ensure that the circuit boards delivered to customers can be used normally without delaying production.
We sell and maintain some imported precision measuring instruments, such as electronic online testers, logic analyzers, ICT. If you are interested in repairing circuit boards, then maintenance tools and instruments are essential. You should be familiar with the hardware, and pay more attention to the new components and their applications. Because every circuit board upgrade is based on hardware upgrading. Only by repairing complex circuit boards with more hands can you continuously improve your maintenance ability.