220-1101 Hardware Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Replace the CPU with a known-good one

  Why it's wrong here

  Replacing the CPU with a known-good unit is premature and likely ineffective here. The CPU diagnostic LED is actually a signal that the motherboard is failing to initialize the processor, which commonly stems from missing microcode support in the current BIOS/UEFI revision rather than a hardware defect. If the original processor was previously functioning, the odds of a sudden CPU failure are low, and swapping in another CPU without first updating firmware would simply repeat the same unrecognized-device condition. The correct sequence is to verify the motherboard's compatibility list and flash the latest BIOS before considering any hardware replacement.

• ✓

  Update the motherboard's BIOS/UEFI firmware

  Why this is correct

  Updating the motherboard's BIOS/UEFI firmware is the appropriate remedy because the processor itself is listed as compatible, indicating a socket match, but the firmware may predate the CPU's release and lack the necessary microcode patch. Without this microcode, the chipset cannot properly configure the CPU's voltage regulators, memory controller, or power states, and the diagnostic LED will remain lit. A BIOS update adds the required microcode and CPU microarchitecture support, allowing the system to complete POST. This directly addresses the root cause and is the established fix for a CPU diagnostic LED after upgrading to a newer processor.

• ✗

  Reseat the RAM modules

  Why it's wrong here

  Reseating the RAM modules is an incorrect action because the CPU diagnostic LED is specifically tied to the processor's initialization phase, not to memory training or detection. If there were a memory problem, the motherboard would typically illuminate a separate DRAM indicator or issue a distinct beep code, not the CPU LED. Moreover, a CPU that is being recognized but waiting for microcode will fail regardless of whether the DIMMs are properly seated. Memory reseating is a valid troubleshooting step for no-POST scenarios, but it does not provide the firmware-level CPU support that this situation requires.

• ✗

  Test the power supply under load

  Why it's wrong here

  Testing the power supply under load is not the correct next step because the system is already powering on and spinning fans, which indicates that the 12V rails and standby voltages are present and the PSU is passing basic power-on self-test. A defective or insufficient PSU would more likely cause random resets, shutdowns, or no power at all, rather than illuminating a CPU error LED during early initialization. Additionally, a CPU compatibility issue is a firmware state problem; no amount of PSU testing will inject the new CPU's microcode patch into the firmware. The power supply test would only verify expectations of voltage accuracy and timing, which are not in question here.

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