54. A technician replaced a failed PSU on a high-end workstation PC. Now, the PC fails to POST and does not stay turned on for more than five seconds. Which of the following power connections was most likely forgotten during installation?
Answer: B
The most likely forgotten power connection is the 12V.
The issue of the workstation PC failing to POST and shutting down shortly after power-up suggests that it is not receiving the necessary power to operate its components. The 12V connection is essential for providing power to the CPU and other critical components, making it the most likely candidate to have been overlooked.
A) 5V
The 5V connection is typically used for powering peripherals and some components, but it is not critical for the initial operation of the CPU and motherboard. If this connection were missing, the system would likely still attempt to power on, but not function properly. Therefore, it is less likely to be the cause of the immediate shutdown observed.
B) 12V
The 12V power connection is crucial for supplying power to the CPU and other high-performance components in a workstation. If this connection was forgotten during the installation of the new PSU, the motherboard may not receive enough power to initialize or sustain operation, leading to the symptoms described. This makes it the most likely option that was overlooked.
C) 120V
The 120V connection refers to the input voltage supplied to the power supply unit (PSU), which is necessary for the PSU to function. However, if this connection were missing, the PSU would not turn on at all, resulting in a complete lack of power rather than the system powering on briefly. Thus, it does not fit the scenario described.
D) 220V
Similar to the 120V option, the 220V connection is also related to the input voltage for the PSU. The absence of this connection would prevent the PSU from receiving power entirely, leading to no operation rather than a brief power on. Therefore, it is not a viable explanation for the symptoms of the PC.
Conclusion
The 12V connection is critical for the operation of the workstation's CPU and components. Given the symptoms of the PC powering on for only a few seconds, it is evident that the absence of this connection would lead to immediate failure to POST. All other options either pertain to lower voltage connections or input power requirements that would not produce the same symptoms.