Hiwaf yeah I got a new power supply and I no longer have to unplug the power supply to turn the monitor on. Your test with disconnecting the power supply from the monitor but not the wall proves that it is the power supply that is the problem. You co...
Had the same issue as OP. I decided to purchase a power supply off ebay for $20 instead of dealing with the crappy ASUS rma process and not having my monitor for weeks. New power supply is working fine (I've had it for a day).I will never buy another...
Nico67, did you end up getting the adapter replaced? I had the exact same issue as you. After a few weeks of that, the monitor began not turning back on at all unless I unplugged the adapter from the wall socket and waited 20 seconds then plugged it ...