Connect the power supply's 24-pin connector and CPU power cables to the motherboard, and connect the power switch from the case to the motherboard.

Plugging in the 6- or 8-pin supplementary PCIe power connector means the 168W maximum of the 24-pin supply can be increased ...

Hold your power supply's 20- or 24-pin motherboard-connection plug with the terminals facing you and the plastic locking piece facing upward and the flat edge facing downward.

New motherboard, new PSU, the only thing the same is the case. Seems like a faulty switch based on that, but the switch appears to close and open properly in every other case.

Which side of a PC case power or reset switch is positive or negative? (and can I damage my motherboard by connecting it incorrectly?) No, you won't damage a motherboard by connecting the power ...

Asus's latest volley in the war on PC cables includes routing power supply lines right through the motherboard headers to create a graphics card with no cables.

If a suitable top-PSU-mount case can't be found I'll probably pick up that Carbide. I see it has ample accommodation for running the PSU cable below the motherboard tray.