- A
The monitor's refresh rate is set too high in the BIOS.
Why wrong: BIOS settings don't control refresh rate for external monitors; this is a driver/GPU capability issue.
- B
The HDMI cable is not rated for 4K bandwidth.
Standard HDMI cables may not support 4K; using a high-speed HDMI cable or a DisplayPort cable would resolve this.
- C
The PC's power supply is insufficient for the new monitor.
Why wrong: Monitors have their own power supply; the PC's PSU doesn't affect monitor signal detection.
- D
The monitor's input source is set to VGA instead of HDMI.
Why wrong: While input source can cause 'No Signal', it's less likely than a cable bandwidth issue given the 4K context.
Question 313 of 1,020
4K Monitor No Signal: HDMI Cable
This 220-1201 practice question tests your understanding of display devices troubleshooting. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
During a hardware install, you connect a new 4K monitor to a desktop PC using an HDMI cable. The display shows a 'No Signal' message. The PC boots normally and the monitor is powered on. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Quick Answer
The answer is that the HDMI cable is not rated for 4K bandwidth. This is the most likely cause because a standard HDMI cable, often labeled as “High Speed” or older, lacks the data throughput required to drive a 4K monitor at its native resolution and refresh rate, resulting in a “No Signal” error even though the PC boots and the monitor powers on. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your understanding of display interface limitations and bandwidth requirements—a common trap is assuming the GPU or monitor is faulty when the cable is the bottleneck. Remember that for 4K at 60Hz, you need a “Premium High Speed” or “Ultra High Speed” HDMI cable; otherwise, the handshake fails. A quick memory tip: “4K needs more than just a cable—it needs the right speed label.”
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 HDMI cable is not rated for 4K bandwidth.
The 'No Signal' error most commonly occurs because the HDMI cable lacks sufficient bandwidth to transmit the 4K signal. Many standard HDMI cables are only rated for lower resolutions. If the cable is not High Speed or Premium High Speed HDMI, it may not support 4K at the required refresh rate. The PC boots normally, indicating the GPU is working. BIOS refresh rate settings are rarely used with modern monitors, and power supply is not a factor for monitor signal. Input source mismatch is possible, but if the user connected via HDMI, the monitor should automatically detect it.
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.
- ✗
The monitor's refresh rate is set too high in the BIOS.
Why it's wrong here
BIOS settings don't control refresh rate for external monitors; this is a driver/GPU capability issue.
- ✓
The HDMI cable is not rated for 4K bandwidth.
Why this is correct
Standard HDMI cables may not support 4K; using a high-speed HDMI cable or a DisplayPort cable would resolve this.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The PC's power supply is insufficient for the new monitor.
Why it's wrong here
Monitors have their own power supply; the PC's PSU doesn't affect monitor signal detection.
- ✗
The monitor's input source is set to VGA instead of HDMI.
Why it's wrong here
While input source can cause 'No Signal', it's less likely than a cable bandwidth issue given the 4K context.
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.
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.
What to study next
Got this wrong? Here's your next step.
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.
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Display Devices Troubleshooting — study guide chapter
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FAQ
Questions learners often ask
What does this 220-1201 question test?
Display Devices Troubleshooting — This question tests Display Devices Troubleshooting — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The HDMI cable is not rated for 4K bandwidth. — The 'No Signal' error most commonly occurs because the HDMI cable lacks sufficient bandwidth to transmit the 4K signal. Many standard HDMI cables are only rated for lower resolutions. If the cable is not High Speed or Premium High Speed HDMI, it may not support 4K at the required refresh rate. The PC boots normally, indicating the GPU is working. BIOS refresh rate settings are rarely used with modern monitors, and power supply is not a factor for monitor signal. Input source mismatch is possible, but if the user connected via HDMI, the monitor should automatically detect it.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 18, 2026
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