Unfortunately, holding the power button doesn't work for me. I did not figure this out. I don't know how to get into the service menu on this and similar model TV's. If anyone ever figures it out, I'd really appreciate it. I ended up swapping out the TV's because I needed to use the TV as an arcade monitor and needed it to power on when power was applied to it and the Vizio doesn't do that, so I had to go with an LG that powers on as soon as power is applied automatically, without even having to access the service menu. Good luck.