What's going on

If your ASUS TUF Gaming VG27AQ suddenly reports DisplayPort No Signal—or fails to register a picture when connected via a USB-C to DisplayPort cable—you are likely dealing with a video handshake collapse. The VG27AQ is a 1440p 165Hz IPS monitor that relies on DisplayPort 1.2 protocol timing to sync variable refresh rates (G-Sync Compatible) with your graphics card or laptop.

Because the VG27AQ does not have a native USB-C port, laptop users rely on USB-C to DisplayPort cables that feed DisplayPort Alternate Mode (DP Alt Mode) signals directly into the monitor's DP receptacle. When the monitor's scalar board enters a deep power-saving state or encounters an EDID handshake mismatch, the DisplayPort input stops negotiating video streams, leaving you staring at a blank display.

Symptoms people notice

• The monitor turns on, displays the ASUS TUF Gaming logo, then immediately shows DisplayPort No Signal before entering sleep.
• Using a USB-C to DisplayPort cable from a laptop works temporarily, but disconnects whenever the laptop goes to sleep or changes resolutions.
• The display works normally over HDMI, but switching to DisplayPort yields a black screen.
• Windows detects "VG27AQ" under Advanced Display Settings, but the monitor panel stays dark or refuses to light the backlight.
• Intermittent black-screen flashing when running games at maximum refresh rate (165Hz Overclock mode).

Likely causes

1. Scalar Board Handshake Lockup: The internal micro-controller on the monitor gets stuck in an unhandled power state and fails to acknowledge the DP link training sequence.
2. Incompatible USB-C Cable or Adapter: Cheap or passive USB-C to DP adapters often fail to properly convert DisplayPort Alt Mode lane signals, especially at 1440p resolutions above 60Hz.
3. Corrupted GPU Display State: The graphics card driver gets stuck trying to output an unsupported bit depth or timing parameters over the DisplayPort connection.
4. Signal Degradation at High Refresh Rates: Overclocking the panel to 165Hz pushes DP 1.2 signal integrity to its limits, causing signal drops on sub-standard cables.
5. Damaged DP Female Port: Constant plugging/unplugging can wear out the pins or fracture the solder pads joining the DP connector to the main logic board.

Quick checks first

• Reseat and Test Cables: Re-plug both ends of the DisplayPort cable firmly. Make sure the connector latches click into place completely on both your GPU and monitor.
• Test Standard HDMI: Plug in an HDMI cable. If HDMI gives a picture, you can isolate whether the issue is systemic to the panel or limited to the DisplayPort pipeline.
• Bypass Adapters: If using a USB-C dock or hub, disconnect it and plug a direct USB-C to DisplayPort cable straight into your host device's Thunderbolt / DP-capable Type-C port.
• Force Lower Refresh Rate: In your OS graphics panel, temporarily set the display output to 1440p at 60Hz or 120Hz to check if high-bandwidth modes are choking the connection.

When it's a real hardware fault

If you have verified your cables on another display, tried multiple PCs, and hard-reset the monitor without success, you may be facing a physical hardware defect on the main system board:

• Broken DP Port Pins: Inspect the physical DisplayPort socket on the back of the VG27AQ with a flashlight. Look for bent copper pins or a loose internal plastic housing.
• Blown Protection Diodes: Electrostatic discharge (ESD) caused by hot-plugging DisplayPort cables can blow ESD protection diodes or the DP receiver IC on the board.
• Power Delivery Circuit Failure: Internal rail failures on the scalar board can prevent the 3.3V pin on the DP connector from negotiating proper handshakes.

Soft resets vs board/panel work

Most DP Alt Mode and DisplayPort disconnect issues on the ASUS TUF Gaming Monitor series are logic state glitches. Unplugging power entirely clears the volatile memory on the monitor's controller board, which fixes signal detection 80% of the time.

However, if the DisplayPort port is physically broken or the mainboard IC is fried, resolving the issue requires board-level soldering or replacing the entire mainboard assembly. Internal power supply components carry high voltages even when unplugged; opening the casing should never be attempted unless you are comfortable handling electronics safely.

Next steps

• Check out overall display troubleshooting tips on our Monitors Hub.
• Explore other ASUS Hardware Guides for driver and firmware advice.
• Considering upgrading your screen? Read our latest display benchmarks and hardware evaluations on our Reviews Hub.