iMac A1311 EMC 2389 Not powering up
I have an iMac A1311 EMC 2389 helping a friend fix it.
Suddenly it wont power ON.
Checked on AC power the cpu fan runs continuously but no chine is heard when power button is pressed.
If I hold power button for long the fan eventually turns off. Also a subsequent press of the power button will then prompt the fan to run once again but no chime.
I have taken off the LCD and inspected LEDs
Only LED 1 keeps steady on with AC power supply the rest keep OFF when power button is pressed.
The PSU gets input 240v
Voltage psu pin 1 & 4 is 12v
voltage psu pin 1 & 12 is 12v
voltage psu pin 1 & 11 is 12 v when power button pressed.
Any directions from here or help with schematics and board viewer will be highly appreciated
Thanks and Regards!