When dealing with PCB assembly, the most difficult to predict and solve is the problem of power supply short circuit. Especially when the board is more complex and various circuit modules are increased, the power supply short circuit problem of the PCB assembly is difficult to control.
Heat analysis method
Analysis Introduction :
1. Generally, if the board is not short-circuited with tin, for example, the chip is broken or the capacitor is broken, the resistance GND is generally not 0Ω, more or less, there will be a few Ω or a few tenths of Ω. Using this feature, you can quickly locate .
2. Use a direct current regulated power supply. Adjust the power supply voltage to the voltage of the short-circuit power supply (3.3V short-circuit to 3.3V). Set it to current limiting mode, the limiting current can be set to 500mA, depending on the actual situation.
3. Disconnect the power supply of the PCB assembly board, connect to the set power supply, and see where the circuit board is hot, and where it is hot is usually a short circuit.
4. To see where the heat is, you can use an infrared thermal imager to check. If you don’t have an infrared thermal imager, you can directly touch it with your hands and feel it (be careful not to burn yourself.
Precautions:
The limit current setting of the direct current source needs to be determined according to the actual situation. If the current limit setting is too small, the heat will not be obvious, and no problem can be found. If the current limit setting is too large, the copper wires on the PCB may be burned. You can slowly adjust the current from small to large until you know where the problem lies.
In a word, In the process of eliminating the short circuit of the PCB assembly power supply, we must pay attention to find out and solve the problem effectively.
PCBFuture can start at printed circuit board manufacturing, through to components supply and assembly. We are happy to supply boards and components. After the production is completed, we can provide professional PCB inspection to ensure the quality of the PCB. For more information, please email to service@pcbfuture.com.
Post time: Oct-22-2022