# Remanufacturing of Industrial Electronics: A Case Study from the GCC Region
## 3 Industrial Product Remanufacturing
### Uncovering the Causes of Industrial PCB Problems
#### 3.2.2 Survey Analysis  
The authors analyzed the quantitative data collected from professionals using SPSS version 27.0 and applied descriptive statistical techniques, such as frequency and percentage. In addition, inferential statistics and critical analysis techniques, such as the independent sample \(t\)-test, were used to observe significant differences between unrelated PCB failure causes.  
To summarize and organize the results of this survey on PCB failure reasons, a bottom-up approach was used, sorting them from the most common cause (at the bottom) to the least common. This method is represented in Figure 4, which shows the Tower of Hanoi with 11 disks, with each disk representing a motherboard failure reason. In addition, Figure 5 displays the histogram representing the survey results.  
As a result, the survey revealed active components (shown in Figure 6) based on semiconductors, such as various types of diodes (Zener, TVS, Schottky, Varicap, etc.), transistors (MOSFET, BJT, IGBT), thyristor, and TRIAC, were the most frequently damaged components.  
Therefore, passive components, which are essential elements of analog electronics, tend to fail and require replacement during remanufacturing. Conversely, external factors, such as electrical supply, environmental conditions (such as dust and humidity), product misuse, and electrostatic discharge (ESD), are common causes of product failure due to wear and tear.  
Moreover, industrial EoL products are susceptible to trace problems, such as misaligning electronic components and improper solder joints, which can disrupt the current flow and disconnect subsequent board stages. Therefore, inspecting the PCB during remanufacturing is strongly recommended to ensure minimal defects.  
Figure 4: Sorted PCB failure causes.  
Figure 5: Histogram of PCB failure causes depicting survey results from 25 technicians.  
In addition, the failure of analog and digital ICs is common and can be detected through various testing methods during troubleshooting. For instance, technicians can use an IC tester to check the integrated circuits, while an oscilloscope can display the signals' waveform graphically and a logic analyzer can analyze the data frame.  
Furthermore, customized and complex integrated circuits (ICs) are also susceptible to damage. In particular, microcontrollers (MCU) and microprocessors (MPU), also known as system-on-chip (SOC), can be vulnerable if they are not adequately protected by drivers and voltage regulators that include over-temperature (OTP), over-current (OCP), and over-voltage protection (OVP). Such protection is necessary to prevent external peaks from damaging these crucial components, which are responsible for handling the primary software of the machine.  
The challenge for technicians lies in dealing with programmable ICs prone to damage or corruption of software due to drained storage battery cells. These ICs require a software base self-test (SBST) to check the memories responsible for running the entire program of the motherboard, as well as input and output modules (I/O) and other microcontroller components.  
Finally, it is worth noting that external mechanical forces, such as vibration and shocks, can cause cosmetic damage to the motherboard. However, this type of damage is relatively rare. To minimize the risk, many OEMs opt to protect the PCB by encasing it in a sturdy package with adequate ingress protection (IP) to prevent the entry of solid particles, liquids, and dust.  
In conclusion, this study highlights the challenges in remanufacturing industrial EoL devices at the motherboard level and provides valuable insights for technicians in identifying the most commonly damaged components. As a result, more effective repair techniques can be developed, ultimately increasing the longevity of these valuable products. Furthermore, this contributes to a more sustainable approach to industrial remanufacturing and e-waste management.  
Figure 6: Active Components.