Circuit board repair is a relatively niche technical skill. An experienced repair engineer may need years or even decades of experience and continuous learning to achieve success. This article mainly shares some insights on circuit board repair.
A circuit board consists of a circuit board, components, and software. I personally believe that the capabilities of the repair personnel and the necessary repair tools are very important when repairing circuit boards. Modern circuit boards are difficult to repair relying solely on one person’s experience without the necessary tools. It is not enough to only advocate for testing devices like online testers without emphasizing the quality of personnel. Each industrial control circuit board has different methods of handling. However, the fundamental approach is to identify and replace faulty components. So, should we just replace all the replaceable components on the board?
I have tried replacing components, but it didn’t work. Some components need to be calibrated, focusing on the overall effect. Using online testers and other tools is like sweeping for landmines; marking each component and checking them against the VI curve can help find some faults, but it does not guarantee the board will be repaired. “Because chips that pass the online tester are not necessarily undamaged; chips that pass the test are not necessarily undamaged.” Moreover, not every component can be found in the component library, and industrial control circuit boards are constantly being updated and upgraded, so your testing tools must also be updated continuously.
The quality of the repair personnel directly affects the success or failure of the repair. When repairing a relatively unfamiliar industrial control circuit board without any schematics, a repair engineer needs to have a solid hardware foundation and a thorough understanding of circuit principles and structures. When encountering an unfamiliar circuit board, they should carefully observe the hardware structure to determine the function of the board and ask the client what type of machine tool it is installed on and what kind of alarms it reports.
Once the function of a circuit board is determined, a block diagram of the circuit board should be constructed in the mind, analyzing the alarm information to identify which part has failed.
In industrial control circuit board repair, the technician’s technique is also crucial. Repairing circuit boards is a very delicate task with many components and circuit boards that are easily damaged, so operations must be carried out with great care, using necessary fixtures and auxiliary tools. Disassembly and soldering should be performed skillfully, and one must think through the entire operation process before starting to avoid unnecessary damage. For programmable chips, backups should be made whenever possible; if backups are not allowed, do not attempt to modify them. If it is found that a programmable chip is damaged and no spare or replacement chip can be found, that circuit board cannot be repaired.
Repairing involves not only finding and fixing the faulty components but also the most challenging part: testing whether the repair is successful and debugging on the machine. Regardless of how you repair it, the final product must work when installed on the machine tool, and the circuit board delivered to the client must be functional. This requires testing on the machine before it is sent out. My company has purchased a large number of repair testing platforms and created simulations based on the client’s boards to ensure that the circuit boards delivered to clients can operate normally without delaying production.
Learning circuit board repair technology inevitably requires undergoing a lengthy apprenticeship. During this period, there are many problems, countless tedious tasks, and overwhelming doubts. All of this requires learners to be able to calm down, be humble in their learning, actively discover and solve problems, in order to achieve success in the field of circuit board repair.
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