2011 iMac 27 will not completely start. What do you make of this?

[dn325ci]

I can see here in the forums that the 2011 iMac is famous for video card failure. My 2011 iMac 27 (stock, except for max memory and SSD upgrade) never had a problem until now. It's running the last approved macOS, High Sierra was it?

So here's what happens: push the power button and it makes the start up sound and boots through the apple logo screen. When it gets to the end of the progress bar under the Apple logo, it pauses for a moment and then completely reboots again. This cycle will continue indefinitely until I unplug the iMac or press & hold power button to shutdown.

If I try to startup in safe mode, it does the same as above, but when it gets to the end of the progress bar it just stops entirely. It doesn't nothing more and does not reboot as above.

Is this a video card issue? Is there a way to diagnose further? I'm comfortable opening it up - I installed the SSD upgrade some years ago.

I had planned to purchase a new iMac this year anyway after the impending update. But if this iMac can be fixed for $150 or less, I'd probably keep it around to run some other tasks.

Thanks!
Don

 

[briloronmacrumo]

One thing to try is Apple's hardware test. See this link for instructions.
Most Apple Stores or Apple Authorized Service Providers ( non- Apple stores ) can also run a slightly more sophisticated version of a hardware test for you. Unfortunately, these hardware tests don't identify all problems and opening the mac and looking is the only way to identify an issue(s). Opening the 2011 iMac is possible and not too difficult. As you noted, video card failures are common in these machines and that repair will easily exceed $150 ( there are some replacements sold on Amazon for $189 just for the part ). Hopefully, the hardware tests will point you in a direction. Rebooting issues are often kernel panics induced by a failing RAM chip but I'd bet it's something else.

 

[dn325ci]

One thing to try is Apple's hardware test. See this link for instructions.
Most Apple Stores or Apple Authorized Service Providers ( non- Apple stores ) can also run a slightly more sophisticated version of a hardware test for you. Unfortunately, these hardware tests don't identify all problems and opening the mac and looking is the only way to identify an issue(s). Opening the 2011 iMac is possible and not too difficult. As you noted, video card failures are common in these machines and that repair will easily exceed $150 ( there are some replacements sold on Amazon for $189 just for the part ). Hopefully, the hardware tests will point you in a direction. Rebooting issues are often kernel panics induced by a failing RAM chip but I'd bet it's something else.

Thanks for the idea. I'll give that a shot tonight!

Don

 

[herrdude]

Thanks for the idea. I'll give that a shot tonight!

Don

Friends do not let friends buy the same graphics card on the 27 2011 model. They all die sooner or later. If you are thinking of going down the road and replacing the graphics card, check out this thread: https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/ It gives you many alternatives and you will be able to get Catalina as well!

 

[Juicy Box]

I had similar issues on a dumpster-pulled Mid 2011 27" iMac that a friend of mine found and gave to me because it didn't work.

It ended up being a corrupt HDD and also a fried GPU.

The HDD issue was easy, as I just swapped for an SSD.

The GPU issue was fixed by baking it, and required removing the logic board, which wasn't too hard, but definitely could be intimidating for someone that hasn't done anything like that before.

There is plenty of YouTube videos on baking the GPU (and many other electronics). Basically, remove the GPU, remove the heatsink from the GPU, clean up thermal paste and pads, then put in the oven and bake for 10 minutes. Reapply paste and pads (I used a kit for the Mid-2011 iMac), and put everything back together.

I did this a year ago, and it works great.

BTW-The dumpster find end up being a top of the line, BTO Mid 2011 27" iMac that was selling for over $600 at the time. You never know what you might find in a dumpster.

 

[dn325ci]

One thing to try is Apple's hardware test. See this link for instructions.
Most Apple Stores or Apple Authorized Service Providers ( non- Apple stores ) can also run a slightly more sophisticated version of a hardware test for you. Unfortunately, these hardware tests don't identify all problems and opening the mac and looking is the only way to identify an issue(s). Opening the 2011 iMac is possible and not too difficult. As you noted, video card failures are common in these machines and that repair will easily exceed $150 ( there are some replacements sold on Amazon for $189 just for the part ). Hopefully, the hardware tests will point you in a direction. Rebooting issues are often kernel panics induced by a failing RAM chip but I'd bet it's something else.

Friends do not let friends buy the same graphics card on the 27 2011 model. They all die sooner or later. If you are thinking of going down the road and replacing the graphics card, check out this thread: https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/ It gives you many alternatives and you will be able to get Catalina as well!

I had similar issues on a dumpster-pulled Mid 2011 27" iMac that a friend of mine found and gave to me because it didn't work.

It ended up being a corrupt HDD and also a fried GPU.

The HDD issue was easy, as I just swapped for an SSD.

The GPU issue was fixed by baking it, and required removing the logic board, which wasn't too hard, but definitely could be intimidating for someone that hasn't done anything like that before.

There is plenty of YouTube videos on baking the GPU (and many other electronics). Basically, remove the GPU, remove the heatsink from the GPU, clean up thermal paste and pads, then put in the oven and bake for 10 minutes. Reapply paste and pads (I used a kit for the Mid-2011 iMac), and put everything back together.

I did this a year ago, and it works great.

BTW-The dumpster find end up being a top of the line, BTO Mid 2011 27" iMac that was selling for over $600 at the time. You never know what you might find in a dumpster.

Super helpful input - thank you. I tried the Apple Hardware Test holding down ”D“ while starting. The AHT never came up. It did the same self-reboot routine. However, one interesting thing - if I hold down Option-D to invoke Internet Recovery the spinning globe with “Starting Internet Recovery. This may take a while.” However, no matter how long I waited, the spinning globe never goes away and never comes to another screen.

So I heard you guys to say it could be:
1. Video card
2. RAM
3. Harddrive - although this seems the least likely as I switched to a Samsung SSD 2 or 3 years ago.

Is there a way to trouble shoot the RAM thing first? That seems the easiest thing to confirm or eliminate.

Don

 

[herrdude]

Super helpful input - thank you. I tried the Apple Hardware Test holding down ”D“ while starting. The AHT never came up. It did the same self-reboot routine. However, one interesting thing - if I hold down Option-D to invoke Internet Recovery the spinning globe with “Starting Internet Recovery. This may take a while.” However, no matter how long I waited, the spinning globe never goes away and never comes to another screen.

So I heard you guys to say it could be:
1. Video card
2. RAM
3. Harddrive - although this seems the least likely as I switched to a Samsung SSD 2 or 3 years ago.

Is there a way to trouble shoot the RAM thing first? That seems the easiest thing to confirm or eliminate.

Don

99,999% = GPU
0% = RAM

 

[dn325ci]

99,999% = GPU
0% = RAM

Thanks friend. I’m down with changing the video card. I’m not a gamer. The current video card was fine for me before it burned. I would love to have Catalina though. What do you recommend going with?

 

[herrdude]

Thanks friend. I’m down with changing the video card. I’m not a gamer. The current video card was fine for me before it burned. I would love to have Catalina though. What do you recommend going with?

k1100m or k2100m. They are the pretty cheap and usually have 2gb.

 

[dn325ci]

k1100m or k2100m. They are the pretty cheap and usually have 2gb.

Thanks. Appreciate your input very much. Sorting through that giant upgrade thread is a nightmare.

I'm comfortable to take this iMac apart, as I did to put the SSD in. Is there a way to confirm for sure either visually or otherwise that it is indeed the video card? I expected the iMac to still be able to boot in safe mode with a bad video card and it didn't. Otherwise I'll plunge in and buy a k1100m or k2100m.

 

[herrdude]

Thanks. Appreciate your input very much. Sorting through that giant upgrade thread is a nightmare.

I'm comfortable to take this iMac apart, as I did to put the SSD in. Is there a way to confirm for sure either visually or otherwise that it is indeed the video card? I expected the iMac to still be able to boot in safe mode with a bad video card and it didn't. Otherwise I'll plunge in and buy a k1100m or k2100m.

I understand that if you boot into Safe Mode, it will work because it isn't using the graphics card in the same way. That could be a test.

 

[briloronmacrumo]

So I heard you guys to say it could be:
1. Video card
2. RAM
3. Harddrive - although this seems the least likely as I switched to a Samsung SSD 2 or 3 years ago.

Is there a way to trouble shoot the RAM thing first? That seems the easiest thing to confirm or eliminate.

The 27" 2011 iMac has a RAM access panel on the bottom of the machine. You could do RAM swaps but I wouldn't bother. I only mentioned the RAM because of your reboots symptom. But since you can't get your machine to launch to the OS desktop, it's highly doubtful RAM is the issue ( and it also prevents you from running software like memtest to check the RAM ). I agree with herrdude; this is either a logic board and/or video card failure. Given the age there are probably other contributing factors that you won't know until after opening the machine ( i.e. the thermal paste is probably totally useless at this age ). I would swap the video card and do what ever else needs fixing while you're in there.