How to repair the failure of the embedded industrial computer main board?

When the main board of the embedded industrial computer has common faults, it is usually repaired by checking the board, troubleshooting, and disassembling. So how should we correctly use this method to deal with the common faults of the embedded main board?

Embedded Motherboard

1、 Board checking

1. Observe whether there is burning, burning, bubbling, surface peeling and jack rusting.

2. Electric meter test method:+9V, GND resistance is very small (less than 50 ohms).

3. Check the power supply: for the damaged industrial automation main board, the voltage can be slightly increased by 0.5-1V. After starting, the integrated circuit on the clothes board will be rubbed hard, making the defective integrated circuit heat and be recognized.

4. Logic pen check: check whether the data signal on the input, output and control pole of the key suspect integrated circuit is available and whether it is high or low.

5. Identify each work area: the embedded industrial computer motherboard generally has clear responsibilities in this area, such as: protection area, digital clock area, situation interface area, attitude area, noise generation area, etc.

2、 Debug

1. According to the instructions of the guide, the suspicious integrated circuit will first check whether there are data signals at the input and output ends. If there are no data signals at the input and output ends, check whether the integrated circuit has any control data signals. If any, the IC is likely to be damaged and there is no control data signal, so the previous pole can be verified until the damaged IC is found.

2. It is not necessary to take out the integrated circuit with the same model, specification or program flow from the pole. After starting up, observe whether the embedded industrial computer is in good condition to determine whether the integrated circuit is damaged.

3. Find a short circuit by using the method of wire break and leakage: if you find a short circuit fault between some communication lines and ground wires,+9V or several other integrated circuits that cannot be connected, you can disconnect the lines and measure accurately to distinguish whether it is an integrated circuit problem or a surface wiring problem, or to see whether the status interface is better than other integrated circuits welded to the wrong waveform integrated circuit with data signals, And distinguish the advantages and disadvantages of integrated circuits.

4. Comparison method: find a motherboard with the same content, compare and accurately measure the pin waveform and number of related integrated circuits to determine whether the integrated circuit is damaged.

3、 Disassembly and assembly

1. Cutting and kicking method: do not damage the main board and cannot be reused.

2. Tin dragging method: weld all the tin on both sides of the integrated circuit pins, drag back and forth with a high-temperature soldering iron, and pull out the integrated circuit (the circuit board is easy to be damaged, but the detection integrated circuit can be retained).

3. Baking kebab: put the baking kebab on the alcohol blowtorch, gas stove and heating furnace to bake, and the tin on the main board will melt and the integrated circuit will come out (not easy to master).

4. Tin pot method: make a special tin pot in the heating furnace. After the tin is melted, the integrated circuit to be unloaded on the main board can seep into the tin tank, and the integrated circuit can be removed without damaging the main board, but the mechanical equipment is not easy to manufacture.

5. Electric hot gas welding gun: use a special electric hot gas welding gun to remove the chip, blow off part of the integrated circuit pins to be removed, so that the integrated circuit after soldering can be removed.