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2012 27" iMac - Thunderbolt Issues

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noahc

macrumors regular
Original poster
Oct 12, 2005
162
68
I have been loving my 27" iMac. Today I finally got a Thunderbolt cord so I could start using it in external display mode with my work 15" rMBP. Everything worked fine for awhile -- so I turned it off and went about doing other things. A few hours later I tried again to put it into target display mode (Command F2) and it didn't respond. Re-started both machines, still nothing. I went into the System Profiler and under Thunderbolt on the iMac it says:

Thunderbolt: No hardware was found

On the MBP, it reports that there is a Thunderbolt Bus and the details. This leads me to believe that somehow the Thunderbolt card in the iMac has failed. Any other ideas?
 
B

bonedaddio

macrumors member
Jan 23, 2009
63
0
PA, USA
I'm not sure, but I THINK I recall something about a "waking from sleep" issue like this, did you try powering both all the way down, then powering them up again, then connecting the cord, the CMD-F2?

I may have read about this over on the Apple forums. I was researching this because I wanted to know if I could do the same thing with my late 2011 MBP and the Mac CSR wasn't too sure about it (I googled it right then and there on my phone); I tried it in the store with my own MBP and a 21" iMac, and it worked fine, but I think I saw something about the sleep/wake issue.

Hope this helps, let us know how it turns out. I kind of doubt (and seriously hope) that something is wrong with your TB on your iMac :eek:
 
N

noahc

macrumors regular
Original poster
Oct 12, 2005
162
68
Thanks. Have re-started and tried many different configurations of the cable. The iMac does not pick up any FireWire anything - target display, Target disk mode etc. Anybody else?
 
N

noahc

macrumors regular
Original poster
Oct 12, 2005
162
68
This was solved after a call to Apple support. A reset of the PRAM did the trick!
 
D

denart

macrumors newbie
Jan 7, 2013
2
0
Just added MDP to HDMI to TV from my iMac

Having same problem and I can't get it to work. So how did they reset the PRAM? I am not sure what PRAM is...sorry...still learning! :(
 
fitshaced

fitshaced

macrumors 68000
Jul 2, 2011
1,741
3,632
denart said:
Having same problem and I can't get it to work. So how did they reset the PRAM? I am not sure what PRAM is...sorry...still learning! :(
Click to expand...

You take the baby out and wheel it down the road and back.
 
D

denart

macrumors newbie
Jan 7, 2013
2
0
Thunderbolt issues

fitshaced said:
You take the baby out and wheel it down the road and back.
Click to expand...

Too Funny! But I did figure it out and it didn't involve any babies or PRAMs! Read my response to my own post if you actually have this problem! :)

----------
noahc said:
This was solved after a call to Apple support. A reset of the PRAM did the trick!
Click to expand...

Here is what I did.......It seems as though a simple fix was missing.... I did this and it works just fine...Here ya go!!!!!

I have a 27' imac. I used the Thunderbolt port on the back to a MDP to A HDMI to my 55" Vizio HD 1080p TV. It didn't work until...... I called my Boeing engineer son-in-law (who is a very part time mac person (but smart) and he had me go to...HERE IT IS STEP BY STEP!!!

Open SYSTEM PREFFERRENCES click DISPLAYS. A window opens that will say your mac on the top of the window (mine said- iMac). Then....click ARRANGEMENT (there will be 2 little blue screens inside--1 portrait and 1 landscape view) and check MIRROR DISPLAYS. Now a second window opens with the name of your other display (mine said- VZ55.....which is my TV) (the two little blue screens will now be overlapping) then go to DISPLAYS on same window and choose your RESOLUTION arrow pack on window to SYSTEM PREFFERRENCES click SOUND click on whatever your other display is (mine was VZ55....) choose your resolution (mine was 1080p) and ****POOF**** there it was.... my computer on my TV!!! WALLA!
Good Luck All! :)

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denart said:
Having same problem and I can't get it to work. So how did they reset the PRAM? I am not sure what PRAM is...sorry...still learning! :(
Click to expand...

I figured it out with help! It seems as though a simple fix was missing.... I did this and it works just fine...Here ya go!!!!!

I have a 27' imac. I used the Thunderbolt port on the back to a MDP to A HDMI to my 55" Vizio HD 1080p TV. It didn't work until...... I called my Boeing engineer son-in-law (who is a very part time mac person (but smart) and he had me go to...HERE IT IS STEP BY STEP!!!

Open SYSTEM PREFFERRENCES click DISPLAYS. A window opens that will say your mac on the top of the window (mine said- iMac). Then....click ARRANGEMENT (there will be 2 little blue screens inside--1 portrait and 1 landscape view) and check MIRROR DISPLAYS. Now a second window opens with the name of your other display (mine said- VZ55.....which is my TV) (the two little blue screens will now be overlapping) then go to DISPLAYS on same window and choose your RESOLUTION arrow pack on window to SYSTEM PREFFERRENCES click SOUND click on whatever your other display is (mine was VZ55....) choose your resolution (mine was 1080p) and ****POOF**** there it was.... my computer on my TV!!! WALLA!
Good Luck All! :)
 
E

emoh

macrumors member
Jan 27, 2008
51
0
thunderbolt blackscreen on iMac 27"

Hijacking this thread as I have similar issue.

I tried the thunderbolt cable connection Mid 2011 MacBook Air to the Late 2012 iMac 27".

the screen detection works for the iMac on MBA. I can see the TB connected. However when I click cmd+f2, the iMac screen went blackscreen.

Even though the steps recommended here have been tried and tested, the blackscreen won't get resolved.

Detecting Display, change resolution for iMac to various resolutions, returns blackscreen results.

I've logged a case with AppleCare.
They asked me to do timing snoop as well as capture data to allow further troubleshooting with the iMac & MBA. Am Pending the Engineering Team to revert.

was wondering, could this be a thunderbolt cable issue?
as I did try the thunderbolt cable with iMac and Early 2011 MBP, which gives similar outcome.

:( peeved.

*interestingly, 1st level tech support actually told me that Late 2012 iMac doesn't support Target Display Mode!!! I argued with him that it does support both the Target Display Mode and Target Disk Mode.He has no choice and said he will contact Advanced Tech Support who as since take ownership of my case.
 
T

tigerpaw

macrumors newbie
Jan 26, 2013
1
0
Solved! (for me at least)

I had exactly the same issues being described here. I'd reset my PRAM and tried booting in different orders. Persistently had a "black screen" on the Late 2012 27" iMac when using it as a target display over Thunderbolt from my mid 2012 MacBook Air.

I called Apple support and they got me to safe boot and reboot both machines. Then they asked me to reset SMC (system management controller). Here are instructions http://support.apple.com/kb/HT3964

For the MBA, as you can't remove the battery:
1. Shut down the computer.
2. Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
3. On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
4. Release all the keys and the power button at the same time.
5. Press the power button to turn on the computer.

After this my problem seems to be completely resolved. I hope this helps.
 
E

emoh

macrumors member
Jan 27, 2008
51
0
tigerpaw said:
I had exactly the same issues being described here. I'd reset my PRAM and tried booting in different orders. Persistently had a "black screen" on the Late 2012 27" iMac when using it as a target display over Thunderbolt from my mid 2012 MacBook Air.

I called Apple support and they got me to safe boot and reboot both machines. Then they asked me to reset SMC (system management controller). Here are instructions http://support.apple.com/kb/HT3964

For the MBA, as you can't remove the battery:
1. Shut down the computer.
2. Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
3. On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
4. Release all the keys and the power button at the same time.
5. Press the power button to turn on the computer.

After this my problem seems to be completely resolved. I hope this helps.
Click to expand...

This didn't work for me.

It's been 1 month and 9 days since I logged the case with AppleCare. They have been asking me to capture data, timing snoop for various scenario and corresponds with me every 3-4 days, with me always emailing them for updates.

Useless Engineers! :mad: :(

One moment, Engineer A went on leave, Engineer B took over.
Engineer B, one day on sick leave, next moment on leave. and what not.

My case has dragged and dragged. I dialled AppleCare US and what I was told, they can't correspond with customers' via email. It's against North America Apple Inc. policy to even email customers on case troubleshooting and advisory. (BULLS$*#) every case is via phone correspondence. They can't call overseas line. (even though I gave them a IP phone no.) I used my IP phone no. to dial AppleCare US.

For those in North America, is that true at all??

Truly thinking, is it AppleCare trying to pull a fast one, instead of changing a new iMac for me, they chose to drag so that they will end up giving me a refurbish iMac Late 2012, 27".
 
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