iMac 27 inch (late 2013) - display shows nothing (backlight comes on after a while), no boot chime, fan is running, USB power is active

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iMac 27 inch (late 2013) - display shows nothing (backlight comes on after a while), no boot chime, fan is running, USB power is active

I left my iMac on as usual at night. I don’t often put it to sleep. I’ve had it since 2014.

When I went to use it this morning, I touched a key on my keyboard to wake up the display. But it remained off. I forced it to reboot (held the power key) and still nothing.

The fan turns on. USB power is running because I tested it with a device. There’s no startup chime (I don’t remember putting it on mute).

Update as I’m writing this: I’ve left it on for several minutes and the display backlight has turned on. But nothing is happening yet.

Things to consider:

I recently upgraded the internal HDD to an SSD a few months ago. Did it myself from OWC. It’s been working fine since.

I have a Focusrite Scarlett 2i 2 that spazzes out every now and then. It flickers on and off, and Reason tells me my audio driver stopped working. Unplugging and reattaching it fixes this. But it’ll spaz out again. Never figured out why. I’ve had it for about a year.

I just purchased an Anker USB 3 hub. I haven’t plugged in any additional accessories, but I did move two of the devices to the hub. I moved a MIDI keyboard to the hub, as well as a USB powered 2.5 inch hard drive. This happened a few days ago.

I have tried unplugging the iMac from the rear socket and letting it sit for a few minutes. Done this a few times now.

Any ideas?

iMac 27″, macOS 10.15

Posted on Jun 8, 2020 7:33 AM

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Answer 1

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John Galt

Level 10

146,396 points

Jun 8, 2020 8:58 AM in response to Heronymo

You probably did most of the following already, but review it to confirm you didn't omit any steps.

Begin with If your Mac doesn't turn on.

Read and follow each of its steps, including all the links within it, all the way through and including Step 4, which directs you to:

If your Mac starts up to a blank screen

Read and follow each of it steps also, all the way through and including the end, which takes you to:

"If you still need help, please contact Apple Support."

As you know Apple will probably disown you the moment you mention having installed an aftermarket SSD, so you might want to skip that exercise in frustration and accept the fact it might be the cause. Perhaps it simply failed, despite the fact I have yet to experience a single failure of any of their Mercury Extreme Pro 6G models. The oldest one is approaching its tenth year in operation; much more than I would have expected.

Your options may amount to pursuing a solution through OWC, or to revert your Mac hardware to a supported configuration.

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Answer 2

Heronymo Author

Level 1

84 points

Jun 8, 2020 9:08 AM in response to John Galt

Thanks for the reply!

I have tried those steps, yes. And I called Apple. Did mention the ssd, but the guy just acknowledged it and ran through some more troubleshooting with me.

I am waiting to hear back from a local authorized service place to see if they can take a look at the hardware.

In the meantime, I didn’t even think of trying to boot with the old hard drive! Good idea. I no longer have the OWC tools to open up the iMac to swap the drive back in, but I do have an external drive case that I can put the old HDD into and try to boot externally. I’ll try this and update this thread when I do so.

The SSD I got was the Electra model, but it would be strange if it failed after only a couple of months. But if the iMac boots up from the external drive, then I’ll definitely give owc a call!

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Answer 3

John Galt

Level 10

146,396 points

Jun 8, 2020 9:11 AM in response to Heronymo

If you have an external enclosure in which to install a startup disk then definitely try booting from it. Success would effectively narrow down the cause to the SSD, on which you might consider at least reinstalling macOS. That or using Disk Utility would be a harmless first step.

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Answer 4

Jun 8, 2020 9:25 AM in response to Heronymo

Reset the System Management Controller (SMC) on that Late 2013 iMac by simply unplugging it from the power source for 15 seconds, and then reconnect power. Try booting again. Apologies if this is redundant to steps you have already taken.

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Answer 5

Heronymo Author

Level 1

84 points

Jun 8, 2020 9:31 AM in response to John Galt

I’ve connected the original drive externally but no success. I can’t even bring up the startup disk selection screen. Recovery mode also doesn’t work. The backlight still isn’t immediately coming on (though it probably would eventually like last time, if I leave it on long enough).

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Answer 6

Heronymo Author

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84 points

Jun 8, 2020 9:30 AM in response to VikingOSX

Thanks! Yes I’ve tried that a few times now. Nothing.

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iMac 27 inch (late 2013) - display shows nothing (backlight comes on after a while), no boot chime, fan is running, USB power is active

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