Circuit Engineering Co.,Ltd

PCB Card Reverse Engineering Analysis

PCB Card Reverse Engineering Analysis


It has been approved that even if the schematic is correct, the electronic device reliability will be doubted if the PCB card reverse engineering is not well. For example, if the two parallel lines on the PCB card being reverse engineeringed very close to each other, will cause the delay of signal wave transmission, and generate the reflect noise at the end of transmitting line; interference caused by inappropriate consideration of power supply, grounding will degrade the performance of product. As a result of that, when reverse engineering PCB, proper reverse engineering measure must be taken to ensure all the switch power supply can have four current reflow:

1> Power supply switch alternative reflow;

2> Output rectification reflow;

3> Input signal source current reflow;

4> Output overload current reflow;

Input reflow charge the capacitor on the PCB card through direct current resemble when reverse engineering PCB card, wave filtering capacitor play the role of wide band energy storage functions. Similarly, output wave filtering capacitor can be used to store the high frequency energy comes from the rectifier, and eliminate the DC energy of output overload reflow. Consequently, output and input wave filtering capacitor wire connection point is critical when reverse engineering PCB card, if the output/input current reflow and power supply switch fail to connect with connecting point of capacitor, alternative energy can radiate to environment through output or input wave filtering capacitor.

Power Supply switch of Alternative route back and rectifier’s AC route back will contain the high level ladder shape current when reverse engineering PCB card, inside this current there are a great deal of harmonic wave which has a much higher frequency then switch basic frequency.

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