Screen turns off after 1 or 2 minutes after booting
I have an iMac A1207 20" 2.16 Ghz.
It starts to blank the screen 1 or 2 minutes after booting but the computer remains working. I can even make it to sleep and the awake it from sleep so the screen turns on, but after some seconds it turns off again.
When I left the iMac disconnected from power outlet, the screen remains turned on for more time (like a whole day). But then when the screen starts to turn off, it keeps turning off frequently.
So I have to leave the iMac disconnected from the power outlet.
Does anybody know what is the problem?
I am almost sure it is a hardware problem but which part I should replace? Backlight Inverter board? Heat sink sensor? Which heat sink sensor? LCD? Graphics Card?
Thanks in advance!
Ist dies eine gute Frage?