220-1101 Question 414
Single answerIncorrect input sourceA user reports that their desktop PC is powered on and they can hear the Windows login sound, but the monitor displays only a blue screen with the message "No signal." The monitor's power light is on, and the video cable is firmly connected at both ends. The user recently connected the PC to a second display for a presentation and then brought the system back to their desk. Which of the following should a technician check FIRST to resolve the issue?
- A
Change the monitor's input source to the port currently connected to the PC
- B
Reinstall the graphics driver in Windows Safe Mode
- C
Replace the monitor because the blue screen indicates panel failure
- D
Reset the motherboard BIOS to factory defaults
Show answer and explanation
Correct answer: A
Explanation
This question tests practical display troubleshooting in a common support scenario. In A+ Core 1, technicians are expected to begin with basic, noninvasive checks such as confirming power, cable seating, and correct input source selection on the display. Monitors commonly have multiple inputs, and after being used in a different environment, they may remain set to the wrong source. Manufacturers such as Dell, HP, Lenovo, LG, and Samsung document input selection as a standard first step when a monitor reports "No signal." More advanced steps like driver reinstallation, hardware replacement, or BIOS changes should only be considered after verifying the monitor is set to the active input carrying the PC's video signal.
- A. Correct.
Correct. A monitor showing "No signal" while powered on often indicates that it is not set to the active input source, especially after being used with another display setup. If the PC and monitor are both powered and the cable is connected, checking the monitor's selected input (such as HDMI, DisplayPort, DVI, or VGA) is a fast and appropriate first troubleshooting step.
- B. Incorrect.
Incorrect. A graphics driver problem is less likely when the user can hear the system boot normally and the monitor itself specifically reports "No signal." That message usually comes from the monitor not detecting video on the selected input, not from a Windows driver issue. Reinstalling drivers is more invasive and should come after basic physical and display-source checks.
- C. Incorrect.
Incorrect. A blue screen generated by the monitor with a "No signal" message does not indicate panel failure. It typically means the monitor is functioning well enough to display its own on-screen status message but is not receiving video on the selected input. Replacing the monitor at this stage would be premature.
- D. Incorrect.
Incorrect. Resetting the BIOS is not an appropriate first step for this symptom. BIOS issues can affect display output in some cases, but when a monitor shows "No signal" after a recent multi-display setup change, the more likely cause is an incorrect monitor input selection. Best practice is to start with the simplest, least disruptive checks.