CompTIA A+ Core 1 (220-1201)Hardware and Network TroubleshootingEasy

A client reports that their desktop computer occasionally fails to power on completely. When it does, the power LED on the front of the case flickers, and the system emits a series of short, repeated beeps. What is the MOST likely cause of this issue?

  1. AA failing CPU fan
  2. BInsufficient RAM installed
  3. CA faulty power supply unit (PSU)
  4. DAn outdated BIOS firmware
Show answer & explanation

Correct answer: C. A faulty power supply unit (PSU)

Flickering power LEDs and repeated short beeps often indicate a problem with the power delivery to the system components. A faulty power supply unit (PSU) is the most common cause of these symptoms.

Why the other options are wrong

  • A. A failing CPU fan would typically lead to overheating warnings or system shutdowns, not power-on issues and flickering LEDs.
  • B. Insufficient RAM might cause boot failures or specific beep codes, but not typically a flickering power LED during initial power-on attempts.
  • D. An outdated BIOS firmware is unlikely to manifest as flickering power LEDs and repeated beeps during the power-on sequence; it's more associated with compatibility or boot issues.

Faulty Power Supply Unit (PSU)

A malfunctioning power supply that fails to deliver stable and sufficient electrical power to the computer components.

  • Can cause intermittent power-on issues.
  • Symptoms include flickering power LEDs, repeated short beeps, or no power at all.
  • Often requires replacement to resolve.

Memory trick: Power problems often start with the supply, making the lights flicker and the system beep repeatedly.

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