220-1202 Practice Question: A technician is installing a new power supply in…

Answer analysis

Option-by-option breakdown

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

• ✗

  The power supply is not compatible with the motherboard.

  Why it's wrong here

  A power supply incompatibility with a motherboard typically involves incorrect physical form factors (e.g., ATX vs. proprietary), insufficient wattage for the system's components, or incompatible power connectors (e.g., 20-pin vs. 24-pin ATX, 4-pin vs. 8-pin EPS). While such an incompatibility would prevent the system from powering on or operating stably, it is generally a design or component mismatch issue, not a direct safety oversight during the installation process like an incorrectly configured voltage switch.

• ✗

  The power cord is not securely plugged into the power supply.

  Why it's wrong here

  A loose or unplugged power cord is a fundamental connection error that would simply prevent any electrical power from reaching the power supply unit (PSU) and, consequently, the computer's internal components. While frustrating and a common reason for a system not powering on, it does not pose an immediate safety hazard in the same way an incorrectly configured voltage selector switch does, which can lead to component damage or electrical arcing. It is a functional oversight, not a safety one.

• ✓

  The voltage selector switch on the power supply is set to the wrong voltage.

  Why this is correct

  Many power supplies include a manual voltage selector switch (typically 115V for North America/Japan or 230V for Europe/most other regions) to accommodate different regional electrical standards. Setting this switch incorrectly, such as to 115V in a 230V region, can cause immediate and severe damage to the power supply due to overcurrent, potentially leading to smoke, sparks, or even fire, making it a critical safety oversight during installation. Conversely, setting it to 230V in a 115V region would likely prevent the system from powering on due to insufficient voltage.

• ✗

  The power supply fan is blocked by debris.

  Why it's wrong here

  A power supply fan blocked by debris would primarily impact the unit's ability to dissipate heat effectively, leading to overheating and potential thermal shutdown or component failure over time. However, a blocked fan would not typically prevent the computer from powering on initially, as the fan's function is for cooling during operation, not for the initial power delivery sequence. Therefore, it is a long-term reliability concern rather than an immediate power-on issue or a critical safety oversight like an incorrect voltage setting.

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