Tools: Multimeter and magnifying glass. When holding a circuit board of the injection molding machine to be repaired, you should visually inspect it first, and when necessary, use the magnifying glass. What can you see? You should observe the following aspects:
1. Is there a disconnection?
2. Are electronic components such as resistors, electrolytic capacitors, inductors, diodes, triodes, etc. disconnected?
3. Is there any fracture, adhesion, etc. on the PCB connection line of the circuit board of the injection molding machine?
4. Has anyone repaired it? Which components have been moved? Are there any operational errors such as dry joint, welding-missed joint and reverse insertion?
After confirming that the repaired parts do not have the above conditions, we first use a multimeter to measure the resistance value between the power supply of the circuit board of the injection molding machine and the grounding. If the resistance value is only a few or more ohms, it indicates that some components on the circuit board are broken down or partially broken down, and measures must be taken to find out the broken components. The specific method is to supply power to the circuit board to be repaired and touch the temperature of each device on the circuit board of the injection molding machine with your hand. The hot one will be the key suspect. If the resistance value is normal, the multimeter should be used to measure the electronic components such as resistors, diodes, triodes, field effect transistors, band switches and the like on the board to ensure that the measured components are normal. Problems that can be solved with a multimeter should not be complicated.
Method 2: Outside parts before
Tools: Circuit on-line maintenance tester If circumstances permit, we may find a good product board that is the same as the repaired one as a reference, and then use the double-rod VI curve scanning function to make a contrast test. We may start from the port, and then from the surface to the inside. In particular, the contrast test for capacitance can make up for the defect that it is difficult for the multimeter to measure whether leakage occurs online.
Method 3: Easy parts before difficult parts
Tools: Circuit on-line maintenance tester, electric soldering iron, marker pen To improve the test effect, before carrying out on-line functional test on the circuit board of the injection molding machine, some technical treatment should be done on the repaired board to minimize the negative impact of various interferences on the test process. The specific measures are as follows:
1. Preparations before test. If the crystal oscillator is short-circuited, a pin must be welded to open the large electrolytic capacitor, because the charging and discharging of the capacitor can also bring interference.
2. In the process of test of devices by exclusion method and on-line maintenance test or comparison of devices, you should directly confirm the test results for devices that pass (or are relatively normal) test for recording. If test fails (or is over-tolerance), it can be tested again. If it still fails, you can also confirm the test results first, and then test will be continued until the test (or comparison) of the devices on the board is completed. Then, you can handle those devices that fail to pass the test (or are over-tolerance).
For devices that do not pass the functional on-line test, the tester can be used for a less formal but more practical treatment method. Since the power supply of the tester to the circuit board of the injection molding machine can pass through the test clip to the corresponding power supply and ground pin of the device, if the power supply pin of the device is cut, the device will be separated from the power supply system of the circuit board, and then the device will be subjected to on-line functional test. As other devices on the circuit board will not interfere again, the actual test effect is equivalent to "isolation line", and the measurement accuracy will be greatly improved.
3. You can use ASA-VI curve for scanning and testing to compare devices not covered by test library. As ASA-VI intelligent curve scanning technology can be applied to compare any device test, as long as the test clip can clamp the device and there is another reference board, by comparison test, strong fault detection capability can be achieved. This function makes up for the deficiency that the on-line function test of the device is subject to the test library, and expands the detection range of the tester for the circuit board faults of the injection molding machine.
In reality, it is often impossible to find a good product board as a reference. Moreover, the circuit structure of the board to be repaired has no symmetry. In this case, the scanning and comparison function of ASA-VI curve cannot play a role, while online function test cannot complete the test of every device on the circuit board due to incomplete test library of devices. As a result, the circuit board still cannot be repaired. This is the limitation of the circuit online maintenance tester.
Method 4: Static parts before moving parts
Currently, the circuit on-line maintenance tester can only carry out functional on-line test and static characteristic analysis on the devices on the circuit board, and whether they are completely repaired must go through the test inspection of the whole machine. Therefore, it is better to check whether the power supply of the equipment is correctly supplied to the circuit board of the injection molding machine as required during the inspection.
If you have any questions regarding after-sales service and maintenance of the injection molding machine, please call the service hotline: +886 934-050-360 (Taiwan), or check your local service contact: https://www.fcs.com.tw/en/worldwide.html
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