Definition of a infrared PCBA fault

PCB (printed circuit board component) failure refers to the PCBA in the production, test or use, can not normally achieve electrical functions and mechanical properties, such as circuit failure, signal transmission error, component overheating, short circuit or open circuit and so on.

The causes of PCBA failures

• Design: if the line layout is not reasonable, such as high-speed and low-speed signal line spacing is insufficient, the signal transmission will be abnormal due to electromagnetic interference. Power design error, so that the component power overload, such as resistance excess fixed power heating or even burned, causing fault.
• Components: the use of poor quality components, large tolerance deviation affects the filtering effect. The welding link is bad, such as virtual welding or false welding, the chip pin connection is unstable, and the signal can not be received and sent normally, resulting in function failure.
• Environmental factors: high temperature and high humidity accelerate the aging of components and cause the circuit board to be damp short circuit. Strong electromagnetic interference sources affect internal signal transmission, resulting in signal error or loss.

Detection method of PCBA fault

•  Appearance check: directly observe whether the element is damaged or burnt, check whether the welding point is firm and full, and check whether the dense solder joint has any signs of virtual welding with the help of a magnifying glass.
• Electrical test: use a multimeter to test the circuit short or open circuit, and judge the line connectivity through the node resistance. With the signal generator and oscilloscope, detect signal transmission, according to the output waveform and other parameters to determine whether there is distortion or attenuation.

Solutions to PCBA failures

Component repair: After detecting the damaged components, replace them with the same model and specification components, pay attention to the welding quality, and prevent the introduction of new faults.

Design optimization: when the fault is caused by design defects, re-plan the layout, increase shielding, adjust the wiring spacing or use multi-layer board design to solve the problem.

Environment improvement: heat dissipation device for temperature problem; Humidity problem Dehumidification or moisture-proof packaging; Electromagnetic interference problems are shielded with a shield.