Won't turn on. LED 1 and 2 turn on, not 3.

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iMac Intel 27" Retina 5K Display (Late 2014 & 2015)

Model A1419 / EMC 2806 / Late 2014 or Mid 2015. 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (ID iMac15,1); EMC 2834 late 2015 / 3.3 or 3.5 GHz Core i5 or 4.0 GHz Core i7 (iMac17,1) All with Retina 5K displays

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Kyle Johnson @gnulnx

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发帖于: 2019年11月7日

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Won't turn on. LED 1 and 2 turn on, not 3.

Hey everyone. Recently a system update was being installed, when we lost main power. Afterwards, the computer “wouldn’t turn on.”

I opened it up and checked the diagnostic LEDs - the first one comes on when the power cable is connected, and the second comes on when the power button is pressed.

At this point, the fan starts spinning, but there is no chime, and the third LED does not turn on.

I’ve read that the third LED indicates an issue with the video card.

Is it likely that the video card needs to be replaced, knowing that this issue happened during a system update (you know, when it says DO NOT TURN OFF)?

How should I proceed?

Thanks!

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DanJ @danj

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Ouch! Not good at all!

The lost of power at this critical time point corrupted your systems EFI image. As that was the update process. you interrupted.

Time to visit an Apple Store for them to repair your firmware. Explain what happened so they understand what needs to be done. The may talk you into getting the logic board replaced. It shouldn’t need that!

The repair depot they send the system to will need to gain access to the logic board to re-burn the firmware from their special tools they have.

I’ll be honest here, I’ve not needed to get this done in a long time! So it’s possible they don’t do that anymore.

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Thank you for the reply!

I brought the computer in a few days and it has been a frustrating experience, to say the least.

After having explained my own diagnostic steps and results, they gave me flak about having opened the computer; at one point they were starting an "unless you are an authorized apple repair facility..." spiel, which I had to cut off. What, my eyes don't work because I don't have an Apple badge?

Apparently they "don't do that" anymore. Multiple Geniuses looked at me like I had three heads when I asked if they could reflash the firmware. You know, the EFI. You know, like a BIOS. No? Nothing?

They must be following a step-by-step repair guide, because they insist that they must start with replacing the power supply ($60). If that doesn't work, then they're going to replace the logic board ($550).

They've also reported that they didn't get any diagnostic LEDs. When I told them to check again, they came back and said they're getting 1 LED, and that this is further indicative of a power supply problem as the results are "intermittent".

I suppose that is possible, but I did check the LEDs three times, and each time the results were the same.

What a nightmare.

由 Kyle Johnson 完成的 2019年11月13日

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Thank you for the reply!

I brought the computer in a few days and it has been a frustrating experience, to say the least.

After having explained my own diagnostic steps and results, they gave me flak about having opened the computer; at one point they were starting an "unless you are an authorized apple repair facility..." spiel, which I had to cut off. What, my eyes don't work because I don't have an Apple badge?

Apparently they "don't do that" anymore. Multiple Geniuses looked at me like I had three heads when I asked if they could reflash the firmware. You know, the EFI. You know, like a BIOS. No? Nothing?

They must be following a step-by-step repair guide, because they insist that they must start with replacing the power supply ($60). If that doesn't work, then they're going to replace the logic board ($550).

They've also reported that they didn't get any diagnostic LEDs. When I told them to check again, they came back and said they're getting 1 LED, and that this is further indicative of a power supply problem as the results are "intermittent".

I suppose that is possible, but I did check the LEDs three times, and each time the results were the same.

What a nightmare. — Kyle Johnson

iMac Intel 27" Retina 5K Display (Late 2014 & 2015)

Won't turn on. LED 1 and 2 turn on, not 3.

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