No Signal

Fix Dell U2720Q No Signal Until Replug

EP
Erropedia Team
📅 August 8, 2026 📅 Updated Aug 8, 2026 👁 0 views Hardware – Monitors Intermediate
Your Dell U2720Q shows no signal until you unplug and replug the cable. Here's the exact fix that worked for me, plus why it causes this.

It drives me crazy when a monitor works fine after a replug but won't wake up on its own. You're not alone—this is a known quirk with the Dell U2720Q, especially when you're using USB-C or DisplayPort. Let's cut to the chase and get it fixed.

The Fix: Update Firmware and Change a Setting

First, check your monitor's current firmware. Press the joystick button on the back of the monitor to open the menu. Go to Others > Display Info and note the firmware version. If it's older than M2B102, that's your problem. Dell released this firmware to fix the no-signal-on-wake bug.

  1. Download the firmware from Dell's support site. Search for "U2720Q firmware" and get the file named U2720Q_M2B102.zip or newer.
  2. Extract the zip file. Inside you'll find a PDF with instructions and the actual firmware file, usually U2720Q_0022_0023.exe.
  3. Run the .exe file on your Windows PC. Follow the on-screen prompts. The monitor will go black for a few seconds during the update — that's normal, don't panic.
  4. After the update finishes, the monitor will reboot itself. You'll see a confirmation message on screen.
  5. Now, unplug the monitor from power completely. Wait for 30 seconds. This clears the internal power state that's causing the issue.
  6. Plug it back in and turn it on.

After updating, also check the Others > USB-C Charging setting. Set it to Off if you don't need it to charge your laptop. I've seen this setting interfere with the wake-up signal, especially on MacBooks and some Windows laptops.

Why This Worked

The firmware bug is in how the U2720Q handles the DisplayPort's hot-plug detect (HPD) signal. When your computer goes to sleep, the HPD line goes low. When it wakes up, the HPD should go high and trigger the monitor to switch on. The old firmware missed that rising edge, so the monitor stayed in a low-power state, thinking nothing was connected. Replugging the cable forces a new HPD pulse, which the monitor does catch.

The power cycle after firmware update resets the scaler chip. It's like clearing a browser cache — it wipes any corrupted state that might linger.

Less Common Variations

If you're still seeing the issue after the firmware update, here are other culprits I've run into in the field:

1. Bad USB-C Cable

Not all USB-C cables carry DisplayPort signals. You need a cable rated for DisplayPort Alt Mode and ideally USB 3.1 Gen 2. If you're using a cheap charging cable, that's why it fails. Buy one from a reputable brand like Cable Matters or Anker with the DisplayPort logo on it.

2. The USB-C Port on Your Laptop

Some laptops only have one or two USB-C ports that support DisplayPort. Check your laptop's specs. On a Dell XPS 13, for example, the left USB-C port supports DisplayPort, but the right one might not. Trying the other port can make a world of difference.

3. DisplayPort 1.2 vs 1.4

The U2720Q supports DisplayPort 1.4, but if your video card or dock only handles 1.2, you might get intermittent signal loss. You can force the monitor to use a lower version in the menu: Display > DP Version and select 1.2. This sometimes stabilizes the connection, especially with older docking stations.

4. Power Saving Mode (standby) Versus Off

Go to Power Management in the monitor's menu. Set Power Saving to Off instead of Standard. Standard mode kills the USB hub and sometimes the DP receiver entirely. Off keeps the receiver active, so it's more likely to catch the wake signal.

Prevention

To stop this from happening again, keep your monitor's firmware updated. Dell releases patches for a reason. I'd also recommend using the same cable and port every day — switching between USB-C and DisplayPort can confuse the monitor's EDID settings.

If you use a laptop dock, plug the monitor into the dock's DisplayPort or USB-C port that's known to work. I've seen docks with weak power delivery cause the monitor to drop the signal when the laptop switches to battery power. Make sure the dock's power adapter is plugged in and rated for your laptop's wattage.

Finally, if you've done all this and the problem persists, check if your monitor is still under warranty. Dell's warranty covers firmware issues and hardware defects. You can request a replacement if you're within 3 years from purchase. I've had to do that twice — it's a known weak spot in the U2720Q's design.

That's the full walkthrough. Start with the firmware update, then the power cycle, and you'll probably be done. If not, work through the variations in order. You'll have a monitor that wakes up every time.

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EP
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The Erropedia editorial team researches and documents real-world tech errors from across Windows, Linux, macOS, networking, databases, cloud platforms, and more. Every solution is reviewed for accuracy and updated as software and systems evolve.