iM 4,1-14,4 Scrambled start-up screen, cannot reinstall OS

[joncrossley]

Hi.
We have an old 27 inch iMac (2013 I think) that I cannot re-setup. It has an odd scrambled start-up screen as here.

My task was to reset this with a new OS. I have formatted the hard drive.

I can get to the recovery partition but attempting to reinstall the OS from online just returns a 'Cannot reach server' error. The internet connection is fine, as is the computer date and time, and I have reset the PRAM. I have created a High Sierra update USB drive but on startup with the option key pressed to try to select it..... the screen just remains black.

Is this iMac ready for recycling?

Thanks for any advice.

 

[B S Magnet]

Hi.
We have an old 27 inch iMac (2013 I think) that I cannot re-setup. It has an odd scrambled start-up screen as here.

My task was to reset this with a new OS. I have formatted the hard drive.

I can get to the recovery partition but attempting to reinstall the OS from online just returns a 'Cannot reach server' error. The internet connection is fine, as is the computer date and time, and I have reset the PRAM. I have created a High Sierra update USB drive but on startup with the option key pressed to try to select it..... the screen just remains black.

Is this iMac ready for recycling?

Thanks for any advice.

View attachment 2270780

I don’t think the Mac is ready for recycling*, but to help further, there are a few things to explore/consider:


1) Could you, if you don’t mind, share (or take a pic of) the serial number located on the rear? This will help the community to verify which iMac revision yours is.

2) You were able to see a screen when trying to select the recovery partition, but not beyond. This might give me a hypothesis, pending on what we can learn from #1 above.

3) The “cannot reach server” error is very likely a product of the signing certificates for several versions of OS X/macOS expiring in October 2019. Apple have re-directed users to newer versions of the OS with signing certificates which won’t be expiring for several more years. Here’s an article expanding on the issue (and the fix). Unfortunately, the built-in firmware for many older Macs won’t be aware of this and are looking for OS disk images in a place on Apple’s servers which are no longer valid.

The first task here is probably the most crucial, as it can inform which GPU combo your model shipped.

Also, resetting the PRAM won’t usually have an impact on things like this. Resetting the SMC, however, might.

---

* recycling should always be a remedial/last resort, as for electronics, it’s only marginally less energy-intensive than trashing it; if, ultimately, you give up with it, consider selling for parts or donating locally

 

[joncrossley]

I don’t think the Mac is ready for recycling*, but to help further, there are a few things to explore/consider:


1) Could you, if you don’t mind, share (or take a pic of) the serial number located on the rear? This will help the community to verify which iMac revision yours is.

2) You were able to see a screen when trying to select the recovery partition, but not beyond. This might give me a hypothesis, pending on what we can learn from #1 above.

3) The “cannot reach server” error is very likely a product of the signing certificates for several versions of OS X/macOS expiring in October 2019. Apple have re-directed users to newer versions of the OS with signing certificates which won’t be expiring for several more years. Here’s an article expanding on the issue (and the fix). Unfortunately, the built-in firmware for many older Macs won’t be aware of this and are looking for OS disk images in a place on Apple’s servers which are no longer valid.

The first task here is probably the most crucial, as it can inform which GPU combo your model shipped.

Also, resetting the PRAM won’t usually have an impact on things like this. Resetting the SMC, however, might.

---

* recycling should always be a remedial/last resort, as for electronics, it’s only marginally less energy-intensive than trashing it; if, ultimately, you give up with it, consider selling for parts or donating locally

Hi. Thanks very much for this - the serial is DCPN6013FQPH.

 

[B S Magnet]

Hi. Thanks very much for this - the serial is DCPN6013FQPH.

OK. This translates loosely to a late 2013 model manufactured during the 6th week of 2014 (and likely the 13th built that week, on the “P” assembly line at the “DC” plant in the PRC). Appleserialnumber-dot-info doesn’t seem to like that serial, but there’s enough present for one to manually verify the window of time.

Next up: have you tried following that link I posted at the end of the last reply for resetting the SMC? Although it’s a much newer model than a late 2007 iMac I had to revive once, via SMC (and which brought it back to working again), it’s a process of elimination step to try.

One more thing: do you have another Mac and that USB flash drive handy? The second Mac can be whatever model from the Intel or even Silicon era. I would like to try something a little different which worked for another person here not too long ago. Cheers.

 

[sack_peak]

Is this iMac ready for recycling?

If a larger iMac was available today with a M2 chip I'd say "yes!"

If you try to have it fixed get an estimate. It may be cheaper to sell yours "as is" for spare parts then get a iMac 24" M1.

BTW this is your Late 2013 iMac 27" Core i5 3.4Ghz.

 

[joncrossley]

I don’t think the Mac is ready for recycling*, but to help further, there are a few things to explore/consider:


1) Could you, if you don’t mind, share (or take a pic of) the serial number located on the rear? This will help the community to verify which iMac revision yours is.

2) You were able to see a screen when trying to select the recovery partition, but not beyond. This might give me a hypothesis, pending on what we can learn from #1 above.

3) The “cannot reach server” error is very likely a product of the signing certificates for several versions of OS X/macOS expiring in October 2019. Apple have re-directed users to newer versions of the OS with signing certificates which won’t be expiring for several more years. Here’s an article expanding on the issue (and the fix). Unfortunately, the built-in firmware for many older Macs won’t be aware of this and are looking for OS disk images in a place on Apple’s servers which are no longer valid.

The first task here is probably the most crucial, as it can inform which GPU combo your model shipped.

Also, resetting the PRAM won’t usually have an impact on things like this. Resetting the SMC, however, might.

---

* recycling should always be a remedial/last resort, as for electronics, it’s only marginally less energy-intensive than trashing it; if, ultimately, you give up with it, consider selling for parts or donating locally

Hi there
So I (think I) have reset the SMC a few times. Rather than the lines at power on, there is now a black screen with no sign of the Apple logo. (There is a chime.). Nothing happens. At some point the welcome to Mac OS country selection screen arrives, but again it still won't do much else.
I did try assembling a bootable USB drive, but pressing the option key at start up to select it does..... nothing.

 

[joncrossley]

Any ideas?

 

[B S Magnet]

Any ideas?

Honestly, were your iMac on my desk right now, the only other, non-invasive step I might try to do (and I’m not sure this iteration responds to doing this, as I’ve only ever done this with earlier Intel iMacs) is to — from it powered off — hold the power button long enough (as memory serves, at least ten seconds, possibly as long as 20) to have the board respond with a long, low-to-mid tone beep (one, not unlike the sound of a firmware update boot, which lasts about 2–5 seconds).

After the long tone stops, follow it up by releasing the power button and letting it either start up as it otherwise might or, if it doesn’t try to start up after the beep stops and the button is released, wait a few moments before pressing the power button again to power it up as you otherwise would), too see what comes of it.

Beyond that, I have no other ideas to toss out there beyond, say, finding a working Thunderbolt cable and another, Thunderbolt-port-equipped iMac (whose display is verified to work), and connecting your iMacs to that iMac, via Thunderbolt, per Apple’s steps here, to see whether you can get to the desktop on your iMac (as viewed through the other iMac’s display), to look up “System Information…” (holding down the Opt key whilst pulling down the Apple menu), clicking on the “Graphics/Displays” page, and seeing what that reports.

If you try out the “Thunderbolt Display Mode” steps but can’t get the other iMac to pull up your iMac’s desktop (i.e., the other iMac’s display goes dark or stays dark), then I would hazard a guess that the GPU on your iMac is probably no longer working as intended, or the display cable harness inside the system is improperly seated in its socket (Step 19 on this ifFixit link) on the logic board.

Which means, yes, other than finding another logic board online and swapping them out, then it’s time to mothball, part out, and/or properly recycle your system (or, in the extremely unlikely chance it is the display cable being improperly seated, then re-seating it manually might fix it).