How to Troubleshoot No Signal Issues?

If the SWITCH LED is blinking (indicating no signal detected), follow this troubleshooting guide.

Symptoms

• SWITCH LED is blinking (green for HDMI, blue for DP)

• Solid LED indicates signal is detected

• Blinking indicates no signal

General Troubleshooting Steps

1. Check cable connections

   • Ensure cables are firmly connected

   • Try reseating cables at both ends

   • Verify correct ports are used

2. Verify source device

   • Ensure source is powered on

   • Check source is outputting video

   • Try source with another display

3. Try different cables

   • Cables can fail

   • Use known working cables

   • For HDMI, try HDMI 2.0 certified cables

4. Check correct mode

   • Press SWITCH to toggle between HDMI/DP

   • Ensure mode matches your connection type

HDMI-Specific Troubleshooting

If SWITCH LED is blinking green:

1. Verify power connection

   • HDMI mode requires external power

   • Connect adapter to Type-C PWR

2. Check HDMI source

   • Source must be outputting video

   • Turn on source device first

   • Some sources need TV/monitor to be detected first

3. Test HDMI cable

   • Try included HDMI cable

   • Try cable in another setup

   • Replace if damaged

4. Check source output settings

   • Some devices need output enabled

   • Check resolution settings

   • Try different resolution outputs

Type-C DP-Specific Troubleshooting

If SWITCH LED is blinking blue:

1. Verify DP support

   • Your device’s Type-C port must support DisplayPort

   • Not all Type-C ports have DP capability

   • Check device specifications

2. Try different port

   • Some laptops have multiple Type-C ports

   • Not all may support DP

   • Try each available port

3. Check Type-C cable

   • Must be a data cable (not charge-only)

   • DP-capable cables recommended

   • Try the included cable

4. Device settings

   • Some Android devices need DP/Desktop mode enabled

   • Check display output settings

   • Restart device and reconnect

Quick Diagnosis

LED Status	Likely Issue
Blinking Green	HDMI: No signal, check cable/source/power
Blinking Blue	DP: Device may not support DP, or cable issue
Off	No power (HDMI) or no connection (DP)
Solid	Signal detected, ready

Advanced Troubleshooting

HDMI handshake issues:

1. Power off all devices

2. Connect cables first

3. Power on RecDual Dongle (connect power)

4. Power on source device last

5. Wait for signal detection

DP detection issues:

1. Disconnect Type-C cable

2. Restart source device

3. Reconnect cable

4. Wait for device to detect display

When to Seek Help

If after all troubleshooting:

• Multiple sources don’t work

• Multiple cables don’t work

• LED never shows solid color

Contact support with:

• Device models tried

• Cables used

• Steps attempted

• LED behavior observed

Related articles:

Understanding LED Indicators on RecDual Dongle Why is the LED Not Lighting Up on RecDual Dongle? Supported Devices for RecDual Dongle

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