Chosen Solution
Hello I have this strange problem with my iMac 2009 model.. When the LCD is not connected the indicator lights come ON and it powers up with the fans running. But when I connect an LCD the iMac does not turn ON. There is not even the first light to suggest it is getting power. I have tested the LCD on another iMac and its working fine. I have changed the power supply board and LCD board but still no luck.
@talkit sounds like your panel is shortening out. Check your cables and definitely the connector.
