2009 iMac EMC 2309 No power, no sounds, replaced power supply with new

Hi, I have a 27” EMC2309 iMac. There is no signs of life at all, press the power button-nothing, checked for a diagnostic light on the logic board-nothing. I replaced the power supply with a new one from iFixit but still won’t power on, still no diagnostic lights BUT I checked the voltage coming into the power supply with a tester and it shows 120V. I’m not sure which outgoing plug connections from the power supply I should test to see if the new power supply is outputting any juice.

But even after checking for connections I may have missed, still no life in the iMac. Any ideas?

Thank you Dan, but the image you provided does not represent the EMC 2309 27” late 2009 iMac. I found the Apple Repair manual with images. The diagnostic led’s are actually to the left of the memory slots. They are at the very lowest location on the logic board on the left of the memory.

Apple covered the led’s with black tape so you can’t see them from the inside of the iMac you have to lay the iMac on its back (you don’t even need the LCD removed) and look thru the air vents and from there you can see the lights (if there are any lit).

Apple provided quite a few troubleshooting steps that I haven’t tried yet but will.

Here is the Apple manual for everyone.

ManualsLib - Makes it easy to find manuals online!

The LED section starts on page 23 of the pdf.

This doesn’t make sense to me. The diagram shows LED 4 is closest to the RAM modules but that is the only led lit. The manual says LED 4 indicates that the computer and the LCD panel are communicating. Well the LCD is not even connected to the computer. Maybe Apple messed up the diagram.

2309 LED diagram