220-1101 Hardware Practice Question
A technician is assembling a new desktop computer. After installing the CPU, RAM, motherboard, and power supply, the system powers on for approximately 3 seconds and then shuts off completely. The CPU fan begins to spin and then stops along with the system. The technician rechecks all connections and they appear secure. Which of the following is the MOST likely cause?
⚠ Common exam trap
CompTIA often tests the distinction between the EPS12V (CPU power) and PCIe (GPU power) connectors, as they look similar but are keyed differently, leading candidates to confuse insufficient wattage with a loose or missing CPU power connection.
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
✓
The CPU power connector (EPS12V) is not fully inserted
The EPS12V connector supplies dedicated power to the CPU. If it is not fully inserted, the CPU will not receive power, causing the system to start briefly (as other components power up) and then shut down when the CPU fails to initialize. This matches the symptom of the CPU fan spinning and then stopping with the system.
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 CPU is not compatible with the motherboard BIOS version
Why it's wrong here
A BIOS incompatibility normally leaves the system powered on without POST, with fans spinning and either a CPU status LED, a series of beep codes, or a black screen displaying an error like 'CPU not supported'—the motherboard continues to supply power rather than deliberately cutting it after a fixed interval. The brief run-then-shut-down signature of a loose EPS12V connector points to a power-delivery interruption, not a firmware-level rejection of the processor.
- ✗
The motherboard is not properly grounded to the case
Why it's wrong here
An improperly grounded motherboard—such as a missing standoff, a board shorted against the case, or insufficient mounting-screw contact—usually triggers the PSU's short-circuit/overcurrent protection instantly, so the system never powers up or immediately clicks off when the power button is pressed. A recurring three-second shutdown is too regular and too specific for a grounding fault; grounding faults tend to be random resets or shutdowns under vibration/load rather than an identical timeout during every early boot attempt.
- ✓
The CPU power connector (EPS12V) is not fully inserted
Why this is correct
The 4+4 pin CPU power connector must be firmly seated. If partially connected, the CPU may draw enough power to start cooling fans but insufficient to complete boot, leading to a shutdown after a brief moment.
- ✗
The power supply unit (PSU) has insufficient wattage
Why it's wrong here
A power supply with insufficient wattage does not typically shut down a mid-range build at idle during the first seconds of POST, because CPU and RAM alone draw well under 100W and even a 300W unit can sustain that easily; symptoms surface when the discrete GPU initializes under load, causing lockups, restarts, or shutdowns. The observed 3-second shutdown is a consistent early sequence tied to the CPU power rail, not a current-capacity shortfall—adding a better PSU would not help if the EPS12V pin remains unseated.
Go deeper
Related to this question
Learn chapter
PSU Connector Types: 24-pin, PCIe, SATA
Key term
RAM
RAM (Random-Access Memory) is volatile computer memory that temporarily stores data for quick access by the CPU.
Key term
Dual In-line Memory Module
A Dual In-line Memory Module (DIMM) is a small circuit board that holds memory chips and plugs into a computer's motherboard to provide Random Access Memory (RAM).
About these practice questions
Courseiva writes every 220-1101 question from scratch — 896 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1101 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 220-1101 exam.