What's going on

DisplayPort relies on a complex bidirectional communication link (the AUX channel) between your graphics card and the monitor's internal scaler board. Unlike HDMI, which is generally more forgiving of simple hot-plugging, DisplayPort establishes a strict link training protocol every time the monitor wakes up.

On many BenQ monitors—ranging from the GW office lineup to EX gaming panels and PD professional displays—the monitor's power-saving firmware can get locked in a deep sleep state. When this happens, the monitor fails to recognize the handshake sent by your graphics card, leaving you with a blank screen and a persistent "No Signal" warning.

Symptoms people notice

• The BenQ logo pops up for a few seconds, followed immediately by "No DisplayPort Signal" and black screen standby.
• The monitor works fine over HDMI, but plugging in a DisplayPort cable results in an immediate lose-of-signal message.
• Screen turns black whenever Windows attempts to switch to a higher refresh rate (e.g., 144Hz or 240Hz).
• DisplayPort input is completely ignored while auto-input scanning cycles back and forth endlessly.
• Operating system settings show two active displays, but the BenQ screen remains dark.

Likely causes

1. DisplayPort Handshake Hang: Deep sleep logic in the monitor's firmware stops listening to the AUX channel.
2. Pin 20 Cable Issues: Low-quality DP cables that pass 3.3V power on Pin 20 can flood the monitor or GPU with unwanted back-power, corrupting signaling.
3. DP Version Mismatch: The monitor is forced to DP 1.4 mode, but the graphics card or port only handles DP 1.2 standard bandwidth.
4. Stuck OSD Auto-Detection: The monitor's microprocessor fails to lock onto the digital stream over DP.
5. Driver Corruption: Windows or GPU display drivers sending an unsupported resolution or out-of-range refresh rate.
6. Port Solder Damage: Wear-and-tear or electrostatic discharge (ESD) damaging the physical DisplayPort receiver on the mainboard.

Quick checks first

Before tearing down your setup, perform these rapid non-invasive fixes:

• The Unplug Trick: Disconnect the monitor's power plug from the wall (not just the back of the monitor) for at least two full minutes while leaving the DP cable unplugged. Reconnect wall power first, turn on the panel, and then re-plug the DP cable.
• Bypass Adapters: Avoid cheap DP-to-HDMI or DP-to-USB-C dongles during troubleshooting. Connect DP natively to DP.
• Try Another Slot: Most modern GPUs feature 3 DisplayPort jacks. Switch to a different port on the graphics card to clear single-port handshake locks.
• Driver Clean Reinstall: If you have a second display, boot Windows and run Display Driver Uninstaller (DDU) to wipe graphics drivers before installing fresh software.

For more general display dropouts across other monitor brands, check our broader monitor troubleshooting index.

When it's a real hardware fault

If power cycling, certified VESA cables, and software resets do not restore video over DisplayPort, you may be dealing with a physical component failure inside the monitor.

DisplayPort lines carry sensitive differential signals. Electrostatic discharge (ESD)—such as plugging in a cable while wearing socks on carpet—can easily fry the electrostatic suppression diodes or input receiver pins right behind the connector. Additionally, plugging and unplugging heavy cables can crack the surface-mount solder joints connecting the DisplayPort jack to the printed circuit board (PCB).

If the HDMI port works perfectly but all DisplayPort inputs are completely dead across multiple PCs, the mainboard's DisplayPort demux or scaler IC has likely suffered hardware failure.

Soft resets vs board/panel work

• User-Fixable (Soft): Hard power draining, disabling deep sleep modes in OSD, forced DP version switching, replacing faulty DP cables, driver reinstallation, and operating system display topology resets.
• Not DIY-Friendly (Hardware): Repairing cracked DP port solder points, micro-soldering replacement surface-mount ESD diodes, or replacing damaged BenQ scaler boards. Attempting component-level board repairs without proper hot-air rework gear and schematic knowledge frequently ruins the display controller beyond recovery.

If your screen is out of warranty and you're considering buying a replacement display instead of hunting down obscure mainboards, browse our hardware reviews hub for tested monitors.

Next steps

Start by executing a complete power-drain reset to flush the monitor's microcontroller state. If that brings back the image temporarily, jump into the BenQ OSD menu, disable Auto-Switch, turn off Deep Sleep, and lock the DisplayPort mode to 1.2 or 1.4 depending on your hardware limits. If the port remains unresponsive across different devices and cables, the monitor's mainboard scaler will likely need replacement.