Breadboarding

Andrew wrote: When resting an x370 gaming k4 motherboard prior to installation in a case, I understand that shorting the pins on the front panel header will turn the power on to test for a good post. But how do I safely turn the power off again for installation in the case?

I assume you are not leaving the two Power Switch pins shorted with something after the board has started?

The usual trick to shut off the PC when you are in the UEFI/BIOS, is to press and hold down the power button on the PC case, until the PC turns off. It takes a few seconds holding the power switch down before the board will turn off, but it will turn off.

So in your situation, you would need to short the two Power Switch pins and maintain the short circuit until the board turns off. That has the same affect as pressing and holding down the power switch.

You could also just turn off the PSU with its switch, but that is not as clean and more abrupt than maintaining a short circuit across the two Power Switch pins.