Model A1418 / Late 2012 / 2.7 & 2.9 GHz Core i5 or 3.1 GHz Core i7 Processor

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iMac wont power up, replaced power supply. Bad logic board?

Hello, I have an iMac A1418 . When I press the power button I get no chime, no hard drive spinning up, no fans going. I suspected faulty power supply so I ordered one and replaced it.

I have not plugged the screen in yet, just all the new power supply cables to test but I am still not getting any response from the computer. Things I have tried below.

1. Turned of machine and unplugged all cables. plugged just the power cable back in and tried turning on, nothing.

2. Tried using a different power cable

3. Tried using a different outlet.

4. Replaced with new power supply.

I was informed that their should be diagnostic led's that are next to the ram slots? Would this then mean that I need to disconnect the logicboard to access behind it where the ram is so I can view the diagnostic led ?

again the computer does absolutely nothing when attempting to power on. No chime, no fans, hard-drive does not spin up nothing.

Any help is greatly appreciated.

Answer this question I have this problem too

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No te LED are not next to the ram. You see the LED without disconnecting the logic board. They are right in front of you. A bit lower then the RAM. (see pics in my question)


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I have the same issue with my imac 2011. Were you able to get yours fixed?

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Hi, my story is a little bit different. When I power my iMac on I hear the HD and Fan spinning for 1 second. Then it stops and does the same thing over and over. 1 LED is steady the second LED lights up when the fan and HD start spinning. See pictures. What could be the problem? If the power supply would be damaged there shouldn't be power, LED or spinning HD and fan right (even when it's just for a second right?)

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Cort will be eternally grateful.
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