I have tried apple support but having difficulties getting a response First logged a call back at 09:00AM got the call but didn't have access to machine. They tried to book a call back but system was down. I have not been able to get logged on for a couple of days to book another call back. Got on at about 19:00 last night, booked a call for 22:15 but that call never came. System seems offline again. My ISSUE When the machine is running there is a low level hum emitting from system. My searching points to an inverter issue with the screen. Should I just book a genius appointment or do I need to go through the online support. Has not been a famous easy apple process yet.