iMac (Retina 5K, 27-inch, 2017) black screen problem

shreedx

macrumors newbie
Original poster
Dec 7, 2014
11
1
Hello, I was using my iMac as usual today - did some work in Mac OS X, then booted through bootcamp to Windows and played some PUBG. Suddenly, in the middle of the game (few minutes in), the iMac froze. I waited for couple of seconds and since nothing was happening, I decided to turn it off and on again.

Since then, I was not able to boot. Both Windows and Mac booting never went through. I tried going into recovery screen using CMD + R keys but was not able to do so (it seemed to ignore this keybind and went straight to booting into Mac OS X). After few more attempts to make the iMac work (resetting SMC, NVRAM, basically anything I could possibly find on the internet), things got suddenly even worse.

After one of the reboots, the screen stayed black. Now when I turn the iMac on, I can hear the fan and HDD spinning, but thats about it. Screen stays black and nothing happens.

Have you ever had similar issue? I would be really glad if you guys could help me out here, the iMac is not under warranty anymore and I cannot imagine buying a new one now since this one was very expensive. Thank you.
 

keysofanxiety

macrumors G3
Nov 23, 2011
9,519
24,631
Reset SMC?
  1. Unplug the power cord from the back of the iMac (not from the mains)
  2. Wait 15 seconds.
  3. Plug the power cord back in.
  4. Wait 5 seconds, then press the power button again to turn on your Mac.
 

shreedx

macrumors newbie
Original poster
Dec 7, 2014
11
1
Did this fix the issue? What model was it? Was it the 4.2 i7?
Hi, nope, it did not.

I was, however, able to somehow make the display turn on. It somehow started working after multiple SMC / NVRAM resets and iMac restarts.

Problem is, I am still not able to boot. I get stuck either on the Apple logo with loading bar (infinite reboot loop) or Windows "attempting repair" screen when booting Windows.

CMD + R for recovery does nothing, starts booting as usual and goes into the reboot loop, same goes for internet recovery. Booting from recovery USB does not work either. It shows the Apple logo, starts loading but suddenly reboots. Diagnostics with the "D" key pressed go through and report no issues found. I am uploading photos of the output of verbose mode, which seems to indicate some issues, but I have not been able to find online what do those mean.

Seems like some sort of Kernel panic, but since I am not able to boot any sort of recovery, I have no idea what to do :/ Thank you for any help.
 

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WrightBrain

macrumors regular
May 30, 2009
133
166
Barring trying to start from an external backup, I have no idea. I'm afraid you may have to bite the bullet and take it in for repair. It won't be as expensive as replacing it, and if you raised enough of a stink about it being a new computer and all they may cave and give you a new one.
 

SaSaSushi

macrumors 601
Aug 8, 2007
4,084
479
Takamatsu, Japan
A black screen with just fans and HDD spinning could be a logic board failure, even if you somehow get it to run the AHT diagnostics and it passes.

See this recent thread. If it's out of warranty I'm going to hope that's not the case for you.

Have you added any RAM to the machine? I'd try removing it and booting if possible.

I definitely agree with the advice above to take it in to Apple for a diagnosis.
 

Lethcoeb

macrumors member
Jun 18, 2011
34
8
Houston
I had to return a 2017 27” iMac for a similar problem. Took in for repair twice, both times told it was fixed. Third time I demanded, and received, a refund.
 

WrightBrain

macrumors regular
May 30, 2009
133
166
I had to return a 2017 27” iMac for a similar problem. Took in for repair twice, both times told it was fixed. Third time I demanded, and received, a refund.
What model was it and what was the actual repair? Did they replace the logic board?
 

Lethcoeb

macrumors member
Jun 18, 2011
34
8
Houston
What model was it and what was the actual repair? Did they replace the logic board?
I don’t have the model number but it was a Refurbished 27-inch iMac 4.2GHz quad-core Intel Core i7 with Retina 5K display.
Original “fix” was replacing the RAM.
Second fix was to replace the board where the power cable connects.
When I brought it in the third time I was told that they had also replaced the logic board, but I wasn’t informed of this when I picked it up after the second repair.
Regardless, I asked for and received a refund.
It worked fine for about 6 weeks before it started acting up. It would basically drop power while operating, then I could reboot (only by unplugging it) and it would would maybe boot up then drop power again, or drop power during the boot up sequence.
If I let it sit overnight it would operate, but after a few days the problem would start all over again. It needed to be running for 3-4 days before the problem initiated.
BTW I was told that the next step was to evaluate my “environment” as there was nothing else they could do. Of course, I had been using a 2011 27” iMac at the same desk for 7 years, so I knew the environment was not the issue...
 
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