Troubleshooting experience of the hottest 4 inject

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Fault repair experience of 4 injection molding machines

if you want to repair a relatively unfamiliar injection molding machine circuit board without any schematic diagram, the so-called "experience" in the past is difficult to do anything. Although people with deep hardware skills are full of confidence in maintenance, if the method is improper, it will still work with half the effort. So, what can we do to improve the maintenance efficiency? Based on the long-term experience of injection molding machine maintenance of Xiamen xuzhiguang electromechanical Development Co., Ltd., it is concluded that the following steps should be followed in an orderly manner

method 1: look first and then measure

use tools: multimeter, magnifying glass

when holding a circuit board of an injection molding machine to be repaired, a good habit is first to visually inspect it, and if necessary, with the help of magnifying glass. What are you looking at

it mainly depends on:

1. Whether there is disconnection

2. Discrete components such as resistors, electrolytic capacitors, inductors, diodes, triodes, etc. are disconnected

3. Whether the connecting wire of the printed board on the circuit board of the injection molding machine is broken, adhered, etc

4. Has anyone repaired it? Which components have been moved? Whether there are mistakes in operation such as faulty welding, missing welding, reverse insertion, etc

(4) low scrap rate. After confirming that the repaired parts do not have the above conditions, first use a multimeter to measure the resistance between the power supply and the ground of the circuit board of the injection molding machine. If the resistance is too small, it is only a few or more ohms, indicating that there are components on the circuit board of the injection molding machine that have been broken down or partially broken down, and measures must be taken to find the broken down components. The specific method is to supply power to the repaired circuit board, and touch the temperature of each component on the circuit board of the injection molding machine by hand. The hot one will be the key suspect. If the resistance value is normal, use a multimeter to measure the resistance, diode, triode, FET, toggle switch and other discrete components on the board. The purpose is to first ensure that the measured components are normal. Our reason is that if you can solve the problem with a multimeter, don't complicate it

method 2: from outside to inside

use tools: circuit maintenance instrument

if circumstances permit, it is best to find a good board as the same as the board being repaired as a reference, and then use the dual bar VI curve scanning function together to conduct a good and bad comparison test on the two boards. The starting comparison point can start from the port, and then from the outside to the inside, especially the comparison test of capacitance, It can make up for the defect that the multimeter is difficult to detect whether there is leakage

method 3: easy first and then difficult

use tool: the circuit is in 2 The load has passed the maximum power (such as the transmission mechanism of the hydraulic universal testing machine is faulty). In order to improve the test effect, the line maintenance instrument, electric soldering iron and marking pen

in the functional weight measurement of the circuit board of the injection molding machine, fire, alarm and personal injury are very dangerous When cleaning, use a vacuum cleaner to remove the indoor dust. Before the test, do some technical treatment to the repaired board to minimize the negative impact of various interferences on the test process. The specific measures are:

1. Preparation before the test

short circuit the crystal oscillator, and weld a pin on the large electrolytic capacitor to make it open circuit, because the charging and discharging of the capacitor can also cause interference

2. Use exclusion method to test devices

in the process of testing or comparing devices, for devices that pass the test (or are relatively normal), please directly confirm the test results for recording; If the test fails (or is out of tolerance), you can test it again. If you still fail, you can confirm the test results first, and then continue the test until the devices on the board are tested (or compared), and then go back to deal with those devices that fail (or are out of tolerance). For devices that fail to pass the function test, the instrument also provides an informal but practical treatment method. Because the power supply of the instrument to the circuit board of the injection molding machine can be applied to the corresponding power supply and foundation of the device through the test clip, if the power supply foot of the device is cut, the device will be separated from the circuit board power supply system of the injection molding machine, and then the function test of the device will be carried out, Since other components on the circuit board of the injection molding machine will no longer interfere, the actual test effect is equivalent to "quasi offline", and the accuracy rate will be greatly improved

3. Use asa-vi curve scanning test to conduct comparative test on devices not covered by the test library

because asa-vi intelligent curve scanning technology can be applied to the comparative test of any device, as long as the test clamp can clamp the device, and there is a reference board, through the comparative test, it also has strong fault detection ability for devices. This function makes up for the deficiency that the device function test is subject to the test library, and expands the detection range of the instrument for the circuit board fault of the injection molding machine. In reality, it is often impossible to find a good board for reference, and the circuit structure of the board to be repaired itself does not have any symmetry. In this case, the asa-vi curve scanning comparison test function does not function as a pipette, and the function test cannot be completed to test every component on the circuit board of the injection molding machine due to the incompleteness of the device test library, and the circuit board of the injection molding machine still cannot be repaired, Here is the limitation of circuit maintenance instrument, just like there is no medicine that can cure all diseases

method 4: first static and then dynamic

because the circuit maintenance instrument can only carry out function test and static feature analysis on the components on the circuit board of the injection molding machine at present, whether it is completely repaired must be tested and inspected by the whole machine. Therefore, it is best to check whether the power supply of the equipment is correctly supplied to the circuit board of the injection molding machine as required

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