3 iMac turned off and won't turn on anymore.
Guys, my iMac turned off and doesn't want to turn on again, I realized it was very hot, I even thought it could be some overheating protection, but after hours of turning it off it won't turn on, I notice that when the plug is plugged in, a green LED lights up, but Even pressing the power button it doesn't turn on.
Update (12/12/23)
I decided to test the power supply with a multimeter, using this Apple manual as a reference.
Pin 3 is not supplying voltage.
Pin 4 is supplying 12v, as Led 1 is on when the AC cable is connected.
Pin 11 starts supplying 12V after pressing the power button. It corresponds to LED 2, but LED 2 does not light up after pressing the power button and the iMac does not turn on.
Pin 12 starts to supply 12V after pressing the power button.
Update (12/13/23)
Guys, I was using the incorrect technical manual, I found the one for the iMac 21.5 Late 2009 and did the voltage test using the pins on the logic board.
-Pin 4 has 12v when I connect the AC cable and LED 1 lights up.
-Pin 11 is at 0v when the iMac is off. When I press the power button it goes to 12v, but LED 2 doesn't light up and the computer doesn't turn on.
-Pin 12 is at 4.6v, when I press the power button, it drops to 0v.
Update (12/13/23)
I decided to take photos of the source for you to analyze, something caught my attention, this component looks strange, with these stains.
UPDATE
I decided to record a video showing the test I did with the font, please forgive my bad English.
Atualizar (12/15/23)
@oldturkey03 @Dan Guys, I tested the new power supply, it didn't solve the problem.
So I decided to remove the logic board and visually analyze it, I found this burnt mark that is in the photo, close to the CPU.
Now I'm in doubt because of the following: I have two options. Buying a logic board (I also need to buy new fans) In total I would spend US$131. Or buy a 2011 iMac 27" that has a GPU problem, the iMac would cost US$202.36 + US$51 for the GPU = US$253.36
329 
971 
Is the Green Light you see one of the diagnostic lights inside the iMac?
Ottobunny さんによる
@ottobunnycoder Yes. Of the 4 LEDs, only LED 1 lights up, corresponding to AC power.
Ramon Ferreira さんによる
@ramonferre18311 sounds like you are getting this under control now. You know you can do it. You got this!!!!
oldturkey03 さんによる
@ramonferre18311 so looks like your power button works but your power supply does not. Check it and see if you have any components on there that look like they could be damaged. If it is not your power button and not your power supply, you don't have much left but the logic board and that would be really bad ;-)
LED #2 missing = PSU issue (prime suspect)
oldturkey03 さんによる
@oldturkey03 Could the suspect be the PSU even delivering 12V to pin 11? Which would be the equivalent of LED 2.
Ramon Ferreira さんによる
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