hardMultiple ChoiceObjective-mapped
220-1201 Practice Question: That their laptop's built-in display shows a dim…
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?
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.
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 truly defective LCD panel typically exhibits physical damage like cracks, dead pixels, persistent colored lines, or a complete lack of image, indicating a failure in the liquid crystal matrix itself. Since the user reports a *dim* image rather than a distorted or absent one, the liquid crystal display elements are likely functioning to form the image, but the illumination source is insufficient.
- ✗
The inverter board is failing.
Why it's wrong here
An inverter board is a component found in older laptops that utilize Cold Cathode Fluorescent Lamp (CCFL) backlighting, converting low-voltage DC to high-voltage AC to power the lamp. Modern laptops overwhelmingly employ LED backlighting, which operates on DC power and does not use an inverter; instead, they rely on an LED driver circuit. Therefore, an inverter failure is irrelevant to an LED-backlit display.
- ✓
The backlight LED driver is failing.
Why this is correct
The backlight LED driver is a crucial component responsible for regulating the precise current and voltage supplied to the array of light-emitting diodes that illuminate the LCD panel from behind. A failure in this driver circuit directly results in insufficient power reaching the LEDs, causing the screen to appear extremely dim or completely dark, even though the actual image data is being processed and displayed by the LCD matrix. This perfectly matches the symptom of a visible but very dim image.
- ✗
The graphics card is outputting a low signal.
Why it's wrong here
If the graphics card (GPU) were outputting a low or faulty video signal, this issue would universally affect all connected displays, including both the laptop's internal screen and any external monitors. The fact that an external monitor functions perfectly indicates that the GPU is generating a robust and correct video signal. This isolates the problem to components specific to the laptop's internal display, not the graphics processing unit.
Go deeper
Related to this question
Learn chapter
Laptop Hardware and Components
Key term
Backlight
A backlight is a light source behind a liquid crystal display (LCD) that illuminates the screen so you can see the images and text.
Key term
Motherboard
The main circuit board inside a computer that connects all components so they can communicate with each other and receive power.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.