EliteDesk 800 G4 not waking up from sleep

[mgi7]

Hello,

My computer has started acting up recently (past two months). When it goes into sleep mode, it doesn't wake up completely.

More specifically - the computer wakes up, but the screen remains without signal (black). The computer beeps continuously with the tones that normally indicate detecting new hardware and then removing new hardware (like plugging in and then removing an USB thumb drive for instance). The HDD led on the front of the computer blinks, approximately twice per second.

In some rare cases, pressing Ctrl-Alt-Windows-B until the keyboard buffer is full resets the screen and it powers on. After that, the computer works normally. But lately, even this didn't help.

What I've tried:

- Made sure hibernation support is disabled

- Checked for power management issues with the Windows wizard (totally useless)

- Updated drivers and firmware to the latest versions

- Updated Windows to the latest patches

- Set the graphics board (Intel 630) to 'maximum performance' in the display settings

All to no avail. 

This is extremely annoying, as now the only option to wake from sleep is to power off and then back on the machine. And this defeats the purpose.

Do you have any suggestions for fixing this? Is there a way to debug and see which device causes the issue? I assumed it's the graphics board, but maybe it's something else.

[BeemerBiker]

Some things to try

https://www.technipages.com/how-to-turn-off-monitor-with-keyboard-shortcuts#:~:text=Hit%20the%20Ctrl....

If the WINDOWS + L does not work then .

What brand monitor are you using?  HDMI?  VGA?  DP?

Tried turning off and on the monitor?

Disconnect and re-connect the monitor?

Do you have additional video ports?  The spec stats two DP ports plus optional port

If you have HDMI port then try another cable.

Try another monitor or just a TV set and see if the problem goes away.

If you connect a second monitor does the primary one start working?  If so, the obtain a dummy HDMI or DP adapter and set display to "duplicate"

[mgi7]

Thank you for the suggestions.

The display already has a hotkey (Ctrl-F8), which doesn't do anything in terms of reset.

The monitor is in fact a TV, connected on HDMI. It's been working like this with two different TV models over time, so that's not the problem. Also, the TV is shut down when the computer is on standby and re-opened when the computer is supposed to wake up.

This is not a configuration issue, so a second monitor isn't needed. Nothing has been changed in the Windows config, it just started doing this at some point. 

I don't think the cable is the issue, either. Once the computer is rebooted, it works correctly, in 4k, without any glitches.