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A1418 | EMC 2889 | Late 2015 | 1.6 GHz dual-core Intel Core i5 or 2.8 GHz quad-core Intel Core i5. Released October 13, 2015.

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No power and will not make any sound

I have a iMac Intel 21.5" EMC 2889 that will not power. When it is plugged in there is no sound or anything that would let you know its starting. what I have done so far is as follows. I checked the power button and it makes contact. I also checked the resistance of the input plug to the internal connection with a ohm meter. I have continuity on both wires. I also replaced the power supply with a new one. I even disconnected the hard drive and it still will not make a sound. So I am down two two items I think. The display and the logic board. I am thinking logic. Is this a common item to go out?Has anyone had this issue? If so how did you resolve it. I don't want to buy any more parts unless I know for sure.

Update (04/04/2018)

Thanks for the quick replies. I didn't know they still had the LEDs. I went back to it and plugged it in to see if I had any LED lights on. They were slightly lower on this model but I found them, in case anyone has this issue and don't see them look a little lower than the location on the photo. Anyway I plugged it in and as soon as I did the first LED came on but then went off quickly. I then unplugged it and replugged it in. the second time the LED did not show at all to be on. So after its initial plug in the LED will not come on. I will leave it unplugged and try again. But I only saw one LED come on and it went off quickly. I suspect the logic is bad as well. Would this be a good deduction?

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You might have a bad power supply I would disconnect the logic board and measure the voltages to make sure it was good. If the voltages are present then the logic board is damaged too.

I would strongly recommend you check your AC power making sure the polarity is correct and the ground pin is wired correctly back to the fuse/breaker panel and then check to make sure the line has a 20 Amp service (120 Volt) and the ground of the panel is in good shape to the ground point.

I would also recommend you get a good surge suppressor and/or a good UPS. to prevent a surge from damaging your system again.

da

Hey Willy not an answer but a question. Did you ever fix your mac? I have the EXACT same problem! If you did fix it please let me know what was wrong with it and how you fixed it. I think there is a short in my logic board somewhere.

da

From the best I remember it was the logic board. This has been a while and I think I got a power supply to test it. The power supply didn't fix it. Due to the cost of the logic board I used the rest for parts. We have so many that sometimes if it is a high priced item like logic board I use it for parts to fix others.

da

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It appears the newer iMac's are more sensitive to power surges. Which likely killed your power supply and has damaged your logic board.

Did you check the onboard diagnostic LED's to see what they tell you before you replaced the power supply?

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I would have started there, tell us what they show you now.

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If no sound is produced or there is no sign of life check the LED signs of the Logic Board. From there you should be able to check the light indicators on the logic board itself and see what exactly is going on. If the first LED is lit up then that means that the computer is receiving power but is not processing it properly and is either a bad power supply ( knowing that you replaced it recently it could still be bad, just maybe a faulty one was sent to you, rare but it does happen unfortunately) or a bad Logic board itself. IF you have any other questions just ask!

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Willy Young sarà eternamente grato.
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