Reasons of PCB Circuit Board Failure

Reasons for PCB circuit board failure:

According to relevant data reports, up to 78% of hardware failures are caused by poor PCB soldering processing.

In the case of hardware failure, engineers are willing to spend a lot of time and energy in the debugging and analysis of the prototype, which delays the progress of the project. If they can’t find the failure reason, they will also habitually think that the problem lies in the design of the software and hardware circuits. When actually doing hardware debugging, engineers often consider many high-level potential incentives, but they are unwilling to doubt the most obvious and easy to make mistakes:

Case 1: A large number of decoupling capacitors are densely distributed next to the CPU power supply. Due to the excess solder PCB soldering process, a certain electrical PCB capacitor is short-circuited. As a result, hardware engineers have to troubleshoot the cause of the short-circuit one by one, which takes a lot of time.

Case 2: Due to the virtual welding of a certain signal in the DDR high-speed signal part, the system seems to work normally when transmitting ordinary small data volume, but when doing burst operations with large data volume, such as operating system loading, high-definition movie playback, the system will often report errors. And it is often mistaken for software reasons, and software engineers look at the code to no avail.

Case 3: High-speed signal interface connector, due to a certain signal false welding, PCB welding processing causes the system to work at a lower level.

Case 4: Due to the poor welding of the inductor part, the PWM dimming function of the LED fails. The PCB welding process engineer spends a lot of time to confirm whether it is a software or hardware problem.

Case 5: Due to improper time and temperature control during soldering, the plastic parts inside connectors such as LCD and USB melted and deformed due to high temperature, causing a certain signal to be accidentally disconnected, resulting in no LCD display and no USB communication, which was mistakenly thought it was a software driver problem.

These problems seem simple, but there are also many welding details and steps that are pieced together, and these links are also interlocked with each other, and any error in any link will cause problems. Therefore, in the process of hardware debugging, it is recommended that engineers first observe the welding quality of your prototype.

1. Is the material correct?

2. Is the pin position correct?

3. Whether there is empty welding, virtual welding, or binding tin?

4. Is the solder paste full and reflective after the furnace?

5. Does the structural part of the connector melt at high temperature?

6. Does the chip position correspond to the silk screen?

After inspecting the above “simple and obvious” items, PCB welding process, and then focus on those “advanced” problems! This is the smart choice.