No-Video Diagnostics A monitor’s power LED is on, but the screen remains completely dark. Which of the following is the least likely root cause?

Difficulty: Easy

Correct Answer: System RAM problem

Explanation:


Introduction / Context:
When a display stays dark despite the monitor powering on, the fault could lie with the display, cabling, or the computer’s graphics output. Prioritizing likely causes saves time and avoids unnecessary part swaps.


Given Data / Assumptions:

  • Monitor LED indicates power is present.
  • No image appears on the screen.
  • We are comparing probabilities among common failure points.


Concept / Approach:

The most frequent culprits are simple: loose or disconnected video cables, wrong input selection, or a defective monitor/backlight. A failed GPU or motherboard video output is also plausible. While bad RAM can prevent boot (causing no video signal), it is generally less likely than the direct display path faults when the symptom is specifically “monitor on, screen dark.”


Step-by-Step Solution:

Check cable connections and input selection on the monitor.Test the monitor on a known-good system or test the system with a known-good monitor.Inspect/add a discrete GPU or try onboard graphics outputs.Only after basic checks suspect less common causes like RAM preventing POST video initialization.


Verification / Alternative check:

Swap components systematically: if the monitor works elsewhere, focus on the PC; if a second monitor also stays dark, focus on the GPU/cable.


Why Other Options Are Wrong:

Video cable disconnects and defective monitors are frequent and directly produce a dark screen. Faulty video circuitry in the PC is also common. RAM issues do cause no-POST scenarios, but relative to display-specific faults, they are less likely for this symptom.


Common Pitfalls:

Skipping simple checks (cable, input source), or ignoring monitor OSD messages like “No Signal.”


Final Answer:

System RAM problem

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