from the manual
Phantom Power
Turn on 48V if the connected device requires phantom power,Touch and hold for 1 second to toggle on or off. This prevents accidental operation.
To prevent audible thumps make sure the channel is muted before plugging or unplugging sources while phantom power is on.
Hello, did you ever get your QU-24 phantom power issue resolved? I’m still trying to figure out how to engage it on a fairly new Qu-24 mixer. It definitely is not straightforward.