mediumMultiple ChoiceObjective-mapped
220-1201 Practice Question: A technician is troubleshooting a display that…
A technician is troubleshooting a display that shows vertical lines across the entire screen. The lines persist when a different video cable is used, and the monitor works fine when connected to another computer. What is the most likely cause?
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 graphics card driver is corrupted.
Vertical lines that persist with different cables but disappear on another computer indicate a problem with the graphics card or its driver on the original computer. The monitor is proven good, so the issue is with the video source.
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 panel is defective.
Why it's wrong here
A defective monitor panel, characterized by physical damage or internal component failure, would consistently display artifacts like vertical lines regardless of the input source or connected computer. Since the technician confirmed the monitor functions correctly when connected to a different system, the panel itself is demonstrably not the source of the display issue. This diagnostic step effectively isolates the problem to the original computer's video output chain.
- ✓
The graphics card driver is corrupted.
Why this is correct
A corrupted graphics card driver can lead to improper communication between the operating system, the graphics processing unit (GPU), and the display, resulting in rendering errors such as persistent vertical lines. These drivers are crucial for translating software commands into visual output, and corruption can cause incorrect pixel data to be sent to the monitor. Reinstalling or updating the driver typically resolves these issues by replacing the faulty software instructions with a stable version.
- ✗
The video cable is damaged.
Why it's wrong here
A damaged video cable, such as one with bent pins, frayed wires, or internal breaks, can certainly introduce signal interference or data loss, manifesting as vertical lines, color distortion, or a complete loss of signal. However, the technician's troubleshooting step of swapping the original cable for a known good one, and observing the vertical lines persist, definitively eliminates the cable as the root cause of the display anomaly. This indicates the issue lies upstream or downstream from the cable itself.
- ✗
The monitor's refresh rate is set incorrectly.
Why it's wrong here
An incorrectly configured monitor refresh rate typically results in symptoms like screen flickering, choppy motion, or an "Out of Range" error message displayed on the monitor, indicating the display cannot synchronize with the incoming signal. It does not commonly produce static, persistent vertical lines across the screen, which are more indicative of data corruption or processing errors within the graphics pipeline rather than a timing mismatch.
Go deeper
Related to this question
About these practice questions
One of 972 original 220-1201 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 220-1201 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.