If I waited a bit and then used the sleep trick to get a brief working screen you can see the machine sat at the desktop. You can still hear the chimes and the machine continues to boot in the background we no signs of any other problem preventing it starting. So, from a push button switch/turn on and also from a restart I got a a brief flash of white screen and then the screen goes black. By doing so I was able to do a proper shutdown, I also tested a restart too by using the same method. Just some thoughts and sharing observations while it was playing up yesterday: As the video above shows the screen just dies and by pressing the on/off button you cab put the machine to sleep and then pressing again bring it out of sleep mode which activates the screen for a few brief seconds at best. I'm currently trying to stress the machine into doing it again. I'm still trying to get the damn thing to show the problem again!! Since resetting Nvram the issue stopped straight away and hasn't returned since.hmm. I now have the machine on my workbench and I can't get it to do it's thing now but would still like some advice on what's causing it and maybe if it's repairable? It reminds me of when a laptop screen/inverter goes belly up.
We were still listening to some dance tunes when it did it last time to us when I was asked to have a look by him and the music continued on banging away as the screen went dark. To me it looks like a display panel issue as the machine is still running in the background. Is this a serious issue? Apple have quoted £650+ for a repair including a new logic board. It can last half an hour or maybe only 5 mins but it will start doing this annoying thing at some time or another.
Sometimes he can recover by pressing sleep and then touching the space bar brings everything back but sometimes not. He can be working away with a large Photoshop file and boom the screen will go dark (see vid). My friend has a really nice iMac 27" late 2009 (see below) that has developed a very strange issue. I hoping that somebody with much more Apple experience than me can help please?