Something broke and now all monitors I try read “no signal”, red light on motherboard labeled VGU but GPU is fine.

Troubleshooting a “No Signal” Display Issue: Identifying and Resolving GPU-Related Hardware Errors

Experiencing a sudden loss of display output can be both frustrating and confusing for PC users. Recently, a user reported a scenario where, during gaming, all monitors abruptly displayed a “No Signal” message, accompanied by a red indicator light labeled “VGU” on the motherboard. Despite an initial suspicion of GPU malfunction, further diagnostics revealed the graphics card itself was operational. This situation underscores the importance of methodical troubleshooting and understanding motherboard indicators to diagnose hardware issues effectively.

Understanding the Symptoms

The user described hearing a noise while gaming, followed by all monitors going blank. Subsequent attempts to reconnect the displays resulted in the “No Signal” message. Additionally, the motherboard’s red LED labeled “VGU” lit up, which, according to the motherboard manual, indicates a problem related to the graphics processing unit (GPU).

Common Causes and Diagnostic Steps

Check the GPU Seating and Connections
Ensure the graphics card is firmly seated in the PCIe slot.
Inspect power cables connected to the GPU for secure attachment.
Verify the monitor cables (HDMI, DisplayPort, DVI) are intact and securely connected.
Test with Alternative Monitors and Cables
Use different display cables to rule out faulty wiring.
Connect to a different monitor or display device.
Reset BIOS/UEFI Settings
Sometimes, resetting BIOS to default can resolve hardware detection issues. This can be done by removing the CMOS battery temporarily or using a motherboard jumper.
Check for Motherboard and GPU Damage
Inspect the GPU and motherboard for visible damage or burn marks.
Listen for beeps during POST or check for other indicator lights.
Test the GPU in Another System
Since the GPU was tested at a repair store and found to be functioning, consider testing a known good GPU in the original system to confirm the issue.
Evaluate Power Supply Conditions
Ensure the power supply unit (PSU) is providing adequate and stable power, especially if multiple components draw significant current.
Consult Motherboard Manual for Diagnostic Indicators
The “VGU” LED label points toward GPU issues, but if the GPU passes external tests, other hardware components or motherboard failures could be involved.