The correct answer is to test the power supply output voltages with a multimeter. This is the most efficient next step because a PSU can spin its fan and still fail to deliver proper voltage on the 3.3V, 5V, or 12V rails, which would prevent the system from posting even though it appears to power on. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of the power-on self-test (POST) sequence and the importance of verifying the PSU first before swapping RAM or GPU, as a faulty power supply is a common hidden cause of no-display issues. A frequent trap is assuming a spinning fan means the PSU is good—remember, the fan only indicates the 12V rail is active, not that all rails are stable. For a memory tip, think “PSU first, don’t burst your bubble” to remind yourself that checking power with a multimeter avoids wasted troubleshooting steps.
220-1101 Power Supply Practice Question
This 220-1201 practice question tests your understanding of power supply. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A technician is troubleshooting a PC that powers on but does not display anything on the monitor. The fans spin, and the keyboard lights flash briefly. The power supply fan is spinning. What is the most efficient next step to isolate the issue?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Test the power supply output voltages with a multimeter
Testing the power supply with a multimeter or PSU tester is efficient because it quickly verifies if all rails are within spec. A failing PSU can cause no-post issues even if the fan spins. Other components like RAM or GPU could also be at fault, but checking power first avoids wasted effort.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 power supply immediately
Why it's wrong here
Replacing without testing may waste time if the PSU is fine; the issue could be the motherboard or GPU.
✓
Test the power supply output voltages with a multimeter
Why this is correct
Measuring voltages on the 24-pin and 4/8-pin CPU connectors can confirm if the PSU is delivering proper power, ruling out a common cause.
Related concept
Read the scenario before looking for a memorised answer.
✗
Reseat the GPU and RAM
Why it's wrong here
Reseating components is a good step but should come after verifying power, as a faulty PSU can cause similar symptoms.
✗
Check the monitor cable connection
Why it's wrong here
Monitor cable issues would not cause keyboard lights to flash; this is a system-level problem.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Trap categories for this question
Similar concept trap
Reseating components is a good step but should come after verifying power, as a faulty PSU can cause similar symptoms.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 220-1201 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this 220-1201 question in full detail.
Identify which 220-1201 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Power Supply — This question tests Power Supply — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Test the power supply output voltages with a multimeter — Testing the power supply with a multimeter or PSU tester is efficient because it quickly verifies if all rails are within spec. A failing PSU can cause no-post issues even if the fan spins. Other components like RAM or GPU could also be at fault, but checking power first avoids wasted effort.
What should I do if I get this 220-1201 question wrong?
Identify which 220-1201 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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