- A
The LCD panel is defective.
Why wrong: A defective panel would show distorted images or lines, not just dimness. The fact that an image is visible (though dim) suggests the panel is working.
- B
The inverter board is failing.
Why wrong: Inverters are used in CCFL backlit screens, not LED-backlit screens. LED screens use a driver circuit, not an inverter.
- C
The backlight LED driver is failing.
The LED driver provides power to the backlight LEDs. If it fails, the backlight dims or turns off, making the screen very dim even though the LCD is still receiving signal.
- D
The graphics card is outputting a low signal.
Why wrong: A low signal from the graphics card would affect both internal and external displays. Since the external monitor works fine, the graphics card is not the issue.
Quick Answer
The answer is a failing backlight LED driver. When a laptop’s built-in display is dim and barely visible at maximum brightness, yet an external monitor works perfectly, the issue is isolated to the backlight system rather than the graphics card or LCD panel itself. In LED-backlit screens, the LED driver circuit—often located on the display cable or motherboard—controls the voltage and current to the backlight LEDs. If this driver fails, the backlight dims or shuts off entirely, while the LCD panel still receives a video signal, resulting in a faint, ghost-like image. On the CompTIA A+ Core 1 220-1201 exam, this scenario tests your ability to differentiate between backlight failure and LCD panel failure; a common trap is assuming the entire screen is dead when the external monitor works. Remember the memory tip: “If you can barely see the image, the backlight’s gone—driver’s the culprit, not the panel alone.”
220-1101 Display Devices Troubleshooting Practice Question
This 220-1201 practice question tests your understanding of display devices troubleshooting. 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 user reports that their laptop's built-in display shows a dim image that is barely visible even at maximum brightness. An external monitor works perfectly. The laptop uses an LED-backlit screen. What component is most likely failing?
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.
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 backlight LED driver is failing.
A dim display on a laptop with a working external monitor points to a backlight issue. In LED-backlit screens, the backlight is driven by an LED driver circuit on the display or motherboard. A failing backlight or its driver causes dimness while the LCD panel itself may still function.
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 LCD panel is defective.
Why it's wrong here
A defective panel would show distorted images or lines, not just dimness. The fact that an image is visible (though dim) suggests the panel is working.
- ✗
The inverter board is failing.
Why it's wrong here
Inverters are used in CCFL backlit screens, not LED-backlit screens. LED screens use a driver circuit, not an inverter.
- ✓
The backlight LED driver is failing.
Why this is correct
The LED driver provides power to the backlight LEDs. If it fails, the backlight dims or turns off, making the screen very dim even though the LCD is still receiving signal.
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 graphics card is outputting a low signal.
Why it's wrong here
A low signal from the graphics card would affect both internal and external displays. Since the external monitor works fine, the graphics card is not the issue.
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
Command / output trap
A defective panel would show distorted images or lines, not just dimness. The fact that an image is visible (though dim) suggests the panel is working.
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.
- →
Display Devices Troubleshooting — study guide chapter
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Display Devices Troubleshooting practice questions
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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 backlight LED driver is failing. — A dim display on a laptop with a working external monitor points to a backlight issue. In LED-backlit screens, the backlight is driven by an LED driver circuit on the display or motherboard. A failing backlight or its driver causes dimness while the LCD panel itself may still function.
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.
About these practice questions
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Last reviewed: Jun 18, 2026
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.
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