What's going on

The ASUS ROG Swift PG27AQDM is a premium 240Hz QHD OLED gaming monitor that pushes massive amounts of data across its display interfaces. To hit high refresh rates at 1440p with 10-bit color, the display relies heavily on Display Stream Compression (DSC) over DisplayPort 1.4 and DisplayPort Alt-Mode over USB-C.

When you see a persistent "No Signal" warning, it usually points to a broken digital handshake rather than a dead panel. The monitor and GPU fail to negotiate bandwidth, leaving the monitor stuck in a deep power-saving mode or blocked by an unfinished OLED pixel cleaning state.

Symptoms people notice

• Black Screen with Active LED: The power indicator glows, but the monitor transitions straight from an ASUS logo to a blank display.
• USB-C Power Without Video: Connected laptops receive battery charge through the monitor's Type-C port, but Windows/macOS reports no external display attached.
• DisplayPort Blackouts at 240Hz: Lowering the monitor to 60Hz or 120Hz yields a image, but toggling 240Hz or HDR instantly cuts the connection.
• Pixel Cleaning Lockup: The signal disconnects immediately after the monitor completes its automatic OLED pixel maintenance cycle while idle.

Likely causes

1. DSC Handshake Failures: The GPU graphics driver lost sync with the monitor's Display Stream Compression encoder.
2. Cable Bandwidth Constraints: Using generic cables that cannot maintain DP 1.4 (32.4 Gbps) or DP Alt-Mode speeds.
3. Firmware State Bugs: Early firmware revisions for this ASUS ROG Monitor family are prone to sleep-state lockups.
4. Auto-Input Glitches: Auto-detect gets confused when multiple inputs or USB-C hub devices are plugged in simultaneously.

Quick checks first

• Bypass Hubs & Adapters: Connect your DP or USB-C cable directly from your graphics card or laptop motherboard port straight to the monitor.
• Test HDMI 2.0: Use an HDMI cable to check if you can display an image. If HDMI works, access the monitor menu to update settings or check firmware versions.
• Swap Cables: Try the stock ASUS cables included in the box. Many aftermarket cables fail to isolate Pin 20 on DisplayPort, causing power feedback issues.

When it's a real hardware fault

If hard AC resets, driver updates, and fresh cables fail across multiple host computers, the issue may be hardware-level. Physical port fatigue—where repeated insertion breaks the internal trace pins on the DisplayPort or USB-C receptacle—is common on heavily used setups.

Internal failures usually manifest as a completely uncommunicative mainboard where even the OSD joystick fails to bring up a menu on screen. If the screen remains pitch black across all inputs (HDMI, DP, USB-C) while the power brick is verified functional, the internal scaler board or OLED power delivery stage has likely shorted.

Soft resets vs board/panel work

Soft resets like draining residual power, disabling Auto-Input, and rolling back display driver updates fix roughly 80% of DP/USB-C signal drops on high-refresh OLEDs. Updating your PG27AQDM firmware via the ASUS MCM utility (over USB-A to USB-B upstream) also permanently resolves many sleep-wake bugs.

Opening the casing to work on the internal power board or logic assembly is strictly not a DIY task. OLED panels are fragile, thin, and integrated directly into thermal management layers. If basic troubleshooting fails, explore broader ASUS repair guides or review our monitor problems hub to isolate system-wide GPU faults before seeking hardware service.

Next steps

• Update your monitor firmware directly from the ASUS support hub using a Windows PC and USB upstream connection.
• Clean install your GPU drivers using Display Driver Uninstaller (DDU) to clear corrupt display profiles.
• Check out our hands-on display reviews if you are evaluating replacement options or secondary displays.