Have a Z2 upgraded to Z3 on a 80gig HDD, newest firmware and maps. When I start the HU, the screen is always dark, it boots fine and works, but the screen is dark. If you shine a light on it you can see the menus. If I restart the unit about ten times the screen turns on and works great, and works fine till the next day. I am all googled out, and have yet to find an answer. I've been reading here all day to no avail. Any insight would be greatly appreciated.