Won't boot with Cooler Master case

I have an old 11th-gen Intel motherboard. I tried to put it into a Cooler Master case, but it won’t start. When I press the power button, the fans only spin briefly, and there is no video signal output.
Before doing this, I had already updated the BIOS to version 3.20 and set the Standalone Operation to Enabled.
Once I put the motherboard back into my laptop, it could boot up normally again. I have done this repeatedly several times and feel frustrated.
Can anyone tell me how to troubleshoot the issue further? Thank you very much.

Is it possible to get into the BIOS while in standalone mode in the Cooler Master Case?

I’ve had the same problem, and it seems like what happens is the bios will reset itself after some number of power cycles without a successful boot. That makes it tricky as hell to actually get standalone working on an 11th gen mainboard. I briefly succeeded once by installing Debian with the board in a normal case hooked up to all peripherals, then enabling standalone mode and removing the battery/display/input connections. It did boot after that, but after some fiddling to troubleshoot an unrelated issue it started displaying the issue you describe.

It’s possible that standalone mode would be more reliable on the 11th gen if at least a battery is connected. Kinda ugly to have a laptop battery dangling out of the nice cooler master case but I’d be willing to deal with that to have a standalone mode that stays enabled.

It’s really unfortunate. I’d like to upgrade again but I don’t want my 12th gen mainboard to end up as another expensive paperweight.

I thought after the board saw essentially nothing else was connected that it eventually presumes it is in a standalone state but it takes resetting the EC to do so.

I thought there was a guide for installing the 11th gen boards in the Cooler Master case that talked about this. I know when I first got my Cooler Master case and Motherboard, it hung up after powering on.

The only way to get it actually output video (i.e. standalone mode) was to hold the power button down for 20+ seconds, wait about 10 seconds, and then press it once.

If it did not work, then I pulled the power from it and tried the process again.

That seemed to reset the EC and it saw that it was in standalone (or enough that it would POST with video) and I went in and changed it to Standalone mode.