I have the documentation but is very confusing. I know how to get into the set up mentu (pressing the pk/vu button while turning the mixer on but the documentaion tells me to to set the "R" meter to -24.
Press the PK/VU button multiple times until the meter does the little back and forth dance that it does when you turn it on.
If you need more piece of mind then you can set an attenuation output so that the side led comes on... then exit the setup... now go back in and follow the above instructions and you'll see that the side led goes out... there, everything is stock again with a visible confirmation.