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220-1201 Practice Question: A client brings in a desktop that will not power…
A client brings in a desktop that will not power on. The technician verifies the power cord is connected and the PSU fan does not spin when the power button is pressed. What is the most appropriate next step?
⚠ Common exam trap
220-1201 often tests the temptation to jump to motherboard or CPU replacement when a no-power symptom appears — candidates must remember to isolate the PSU first with a tester before replacing any other component.
Answer choices
Why each option matters
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 using a PSU tester
When a desktop shows no power and the PSU fan does not spin despite the cord being connected, the power supply is the prime suspect. Using a PSU tester verifies whether the PSU delivers correct voltages on each rail without risking other components. This is the logical next diagnostic step before replacing any parts.
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 motherboard
Why it's wrong here
Replacing the motherboard is a significant and often costly repair that should only be considered after more fundamental power delivery components have been thoroughly tested and ruled out. Without first confirming the functionality of the power supply unit (PSU), which is the primary source of power for all components, replacing the motherboard is premature and unlikely to resolve a "no power" issue if the PSU itself is faulty. This approach wastes time and resources on an unverified diagnosis.
- ✓
Test the power supply using a PSU tester
Why this is correct
When a computer exhibits absolutely no signs of power, the power supply unit (PSU) is the most frequent point of failure. A dedicated PSU tester provides an immediate and definitive diagnosis by measuring the voltage output on all critical rails (+3.3V, +5V, +12V, -12V, +5VSB) and verifying the Power Good signal. This tool quickly confirms whether the PSU is delivering correct and stable power within ATX specifications or if it is dead, directly identifying the root cause of the "no power" symptom.
- ✗
Reseat the CPU
Why it's wrong here
Reseating the CPU is an inappropriate initial step for a system exhibiting no power whatsoever, as a CPU issue would not typically prevent the power supply from initiating. If the CPU were the problem, the power supply would usually still turn on, fans would spin, and the system might attempt to POST, albeit unsuccessfully. The complete absence of power activity, such as no PSU fan spin or indicator lights, points to a failure in the power delivery system itself, not a component like the CPU that relies on that power.
- ✗
Check the front panel power switch
Why it's wrong here
While a faulty front panel power switch can prevent a computer from turning on, it is a less common cause of a "no power" symptom compared to a failed power supply. Furthermore, a technician can easily diagnose or bypass a suspected faulty power switch by momentarily shorting the power pins on the motherboard's front panel header. If the system still fails to power on after bypassing the switch, the issue definitively lies elsewhere, most likely with the power supply itself.
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Same concept, more angles
2 more ways this is tested on 220-1201
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A customer brings in a PC that was working fine until they moved it to a new desk. Now it powers on but immediately shuts off after 2 seconds. The technician notes that the CPU fan does not spin at all. What is the most likely cause?
hard- A.The power supply is failing under load.
- ✓ B.The CPU fan header is disconnected from the motherboard.
- C.The CPU is not seated properly.
- D.The case power button is stuck in the pressed position.
Why B: A CPU fan that does not spin at all, combined with an immediate shutdown after ~2 seconds, points to the motherboard's fan tachometer not receiving a signal — typically because the CPU fan header is disconnected. Many systems perform a POST check and halt/shut down if no CPU fan RPM is detected to prevent overheating.
Variation 2. A customer complains that their computer will not turn on. The power supply fan does not spin, and the motherboard LED is off. The technician tests the power supply with a multimeter and gets 0V on all pins. What should the technician do next?
medium- A.Replace the motherboard.
- B.Reseat the 24-pin power connector.
- C.Replace the power supply with a known-good unit.
- ✓ D.Check the wall outlet with a voltage tester.
Why D: The technician measured 0V on all power supply pins with a multimeter, which indicates the PSU is not receiving power or is completely dead. Before replacing the PSU, the next logical step is to verify the power source — checking the wall outlet with a voltage tester confirms whether the outlet is supplying power. If the outlet is dead, replacing the PSU would not solve the problem.
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This 220-1201 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 220-1201 exam.