Monitor screen keeps turning off and on after plugging in phone via HDMI.

Troubleshooting Screen Flickering When Connecting a Smartphone via HDMI: A Practical Guide

Introduction

Many smartphone users rely on their devices for both daily communication and as sources of important data, including photos and documents. Occasionally, connecting a smartphone to an external monitor or display can introduce technical challenges. If you’re experiencing your monitor turning off and on repeatedly after connecting your phone via HDMI, you’re not alone. This article explores common causes and effective solutions to address such issues, ensuring a smoother connection experience.

Scenario Overview

Imagine owning a 5-year-old OnePlus 8 Pro, which recently developed a persistent green screen issue. With no receipt available, the manufacturer’s showroom refuses to replace the display, and the cost for a third-party replacement exceeds your budget as a student. Despite the hardware issues, your goal is to connect the phone to an external monitor for viewing photos and documents.

You attempted to connect the device using a USB-to-HDMI converter and used a mouse instead of the touchscreen for control. However, this resulted in the monitor flickering—turning off and on repeatedly—making it difficult to use. Interestingly, connecting the same tablet to the monitor worked flawlessly, indicating the issue may be specific to the phone’s connection or settings. You have enabled USB debugging but are unsure how to utilize it for further troubleshooting.

Understanding the Issue

Screen flickering or monitor restarts during connection can stem from various causes, including:

• Hardware incompatibilities or faulty adapters
• Incorrect or unstable video output settings
• Power supply issues
• Driver or software glitches on the smartphone
• Faulty or damaged HDMI ports or cables

Since your setup involves a third-party USB-to-HDMI converter, compatibility could also be a contributing factor.

Potential Solutions

1. Check Hardware Components

2. Test with a different HDMI cable or adapter: Swap your current converter for a different one to rule out hardware faults.

3. Use a different monitor or television: Sometimes, compatibility issues arise with specific displays.

4. Review Connection Settings

5. Ensure correct HDMI output mode: Some phones require specific settings for video output. If available, enable or adjust the “HDMI output” or “screen mirroring” options in your device settings.

6. Adjust display resolution: Lowering the output resolution can stabilize the signal.

7. Update or Reset Software Settings

8. Update your device: Check if your OnePlus