Introduction to the steps and techniques of board repair technology
Published time: 2019-08-14
Circuit board repair technology is a relatively high-end, relatively complex technology. Books and articles on circuit board maintenance are very scarce. If you want to learn this technology well, there is a certain difficulty in self-study. Many people say: If you want to learn circuit board repair technology, you must lay a solid foundation, familiarize yourself with every electronic component in the circuit board, master the structure and working principle of each unit circuit in the circuit board, and combine it with practice to master the maintenance. skill". In general, mastering board repair techniques can be learned by following these steps:
The initial stage of board maintenance. First of all, you must be able to understand every electronic component in the circuit board, familiar with the function characteristics of each electronic component, code in the circuit diagram and circuit board, application, quality detection, etc., and then master the circuit board Circuit structure, characteristics, performance parameters, fault mechanisms, etc. Finally, master the skills of common instrumentation and maintenance tools, you can start to repair the circuit board.
Circuit board repair and cultivation phase. This phase is a phase in improving board repair skills, primarily in terms of repair speed. At this time, it is necessary to improve the composition, working principle, function, fault diagnosis process, and maintenance skills of various circuit structures in the circuit board. Master the basic traces of the various electronic components in the board, you can draw the working principle diagram of the board according to the real object, and be able to analyze the signal's ins and outs, power supply and so on.
Circuit board maintenance phase. At this stage, it is necessary to repair some faulty circuits, summarize the rules of fault occurrence, find faults, learn to write maintenance technical articles, etc., and repair a large number of faulty circuit boards to accumulate a wealth of circuit board repairs. Experience, become a hardware maintenance engineer for a technically weak device control system.
First, look at the amount
the circuit board to be repaired, first of all should be visually tested. If necessary, observe with a magnifying glass. Mainly to see: 1. Whether there are broken wires and short circuits; especially whether the printed circuit board connecting wires on the circuit board are broken or stuck; 2. Whether related components such as resistors, capacitors, inductors, diodes, transistors, etc. exist. Disconnection phenomenon; 3, whether there are problems such as virtual welding, leakage welding, plugging and inserting errors.
Second, the first outside and the inside
When using the circuit online maintenance tester for testing, if circumstances permit, it is best to have a good circuit board as the reference to be repaired as a reference. Then use the tester's double-bar VI curve scan function to perform good and bad comparison tests on the two boards. The starting comparison test point can start from the port of the board; then it is tested by comparison between the table and the inside, especially for the capacitor. This can make up for the shortcomings in the multimeter that it is difficult to measure whether the capacitor is leaking.
Third, the first easy and difficult
n order to improve the test results, before the online functional test of the board, the technical processing should be done to repair the board to minimize the impact of various interferences on the test process. The specific measures are as follows: 1. Preparation before testing Short-circuit the crystal oscillator. For large-capacity electrolytic capacitors, also solder the next leg to open the circuit. Because the charging and discharging of large-capacity capacitors also cause interference. 2. Test the device by the exclusion method During the online test or comparison test of the device, if the device passes the test (or is relatively normal), please confirm the test result directly and record it. If the test fails (or is relatively poor), you can test it again. If it still fails, you can confirm the test results first. This is tested until the device on the board is tested (or compared). Then deal with those devices that fail the test (or compare the out-of-tolerance). 3. Compare tests with devices not covered by the test library with the ASA-VI curve scan test. The ASA-VI smart curve scan technology can be applied to the comparison test of any device. As long as the test clip can clamp the device, there is another reference board. Through comparison tests, the device also has strong fault detection and judgment capabilities. This function compensates for the insufficiency of the device test library when the online function test of the device is made, and expands the detection range of the test instrument for the board fault.
Fourth, the first static and then move
As far as the current, only the device on the board for functional online testing and static feature analysis. Therefore, if the faulty circuit board is finally completely repaired, it must be loaded back to the original equipment for inspection. In order to get the correct result of this inspection process, to judge whether the board is repaired. At this time, it is best to check whether the power of the device is correctly supplied to the circuit board as required, and whether the interface plug-ins on the circuit board are properly connected.
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