I just updated my dad's early 2009 Mac mini to Mavericks. After the final reboot, I noticed the monitor, an old LG l1920p, seemed dead. At first I thought the mini was just asleep. But couldn't get it to wake up. Then I noticed the indicator light on the monitor was not on. I can get it to respond or go into the menu mode. Did Mavericks toast the monitor or is this some crazy coincidence? He doesn't have a spare monitor to test but oddly enough, he does have a spare mini with ML on it.