220-1101 Question 420
Single answerFlashing screenA user reports that an external monitor connected to a desktop PC has started flashing on and off every few seconds after the workstation was moved to a different cubicle. The image is visible between flashes, and the PC otherwise operates normally. The monitor works correctly when tested on another computer. Which of the following should the technician do FIRST to resolve the issue?
- A
Replace the monitor because intermittent flashing indicates a failing backlight
- B
Check and reseat the video cable and power cable connections to the monitor and PC
- C
Reinstall the operating system because display flashing is commonly caused by corrupted system files
- D
Replace the motherboard because the video subsystem is failing
Show answer and explanation
Correct answer: B
Explanation
The key clue is that the problem started immediately after the PC was moved. In real-world desktop support and in CompTIA A+ methodology, recent physical changes often point to loose cables, damaged connectors, or power issues. Since the monitor works on another computer, the monitor is less likely to be defective. The best first step is to inspect and reseat the monitor's video cable and power cable at both ends, and if needed test with a known-good cable. This follows standard troubleshooting best practices: identify what changed, start with the simplest probable cause, and use known-good components before replacing major hardware. This aligns with common CompTIA A+ guidance for display issues such as flickering or flashing screens.
- A. Incorrect.
This is incorrect. A failing backlight can cause dimming, intermittent illumination, or a dark screen, but the scenario already states the monitor works correctly on another computer. That strongly suggests the monitor itself is not the root cause. Replacing the monitor first would skip a basic troubleshooting step and increase unnecessary cost.
- B. Correct.
This is correct. Because the issue began after the workstation was physically moved, a loose or partially disconnected display cable or power cable is the most likely cause. CompTIA A+ troubleshooting emphasizes starting with the simplest and most likely physical causes first, especially after a recent environmental or physical change. Reseating connections is a fast, low-risk first step.
- C. Incorrect.
This is incorrect. Operating system corruption is not the most likely explanation for a monitor that flashes after being moved, especially when the display is intermittently visible and the problem points to a physical connection issue. Reinstalling the OS is overly disruptive and would not be an appropriate first action.
- D. Incorrect.
This is incorrect. A failing motherboard or onboard graphics could cause display issues, but that is a less likely first diagnosis given the timing of the problem and the fact that the monitor itself tests fine elsewhere. Hardware replacement should come only after basic cable, port, and configuration checks are completed.