Thunderbolt ports not working on late-2012 iMac 27"

Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
I bought this computer brand new direct from Apple about a year ago. I am trying to connect a 2nd monitor via an HDMI cable and HDMI-Thunderbolt adapter AND a FW800 hard drive via a FW800 cable and FW800-Thunderbolt adapter.

Neither work.

I also have a mid-2012 Macbook Air 13" and BOTH the monitor AND hard drive work flawlessly with the MBA with the exact same cables and adapters.

On my iMac, I just updated to Mavericks, installed all available software updates, and reset the SMC and PRAM. Still no-go. And I tested the monitor and HD between each of those steps, with no luck each time. When I check System Information>Thunderbolt, the devices do not appear there either.

Any other suggestions before I conclude that both my Thunderbolt ports are dead on this barely year old computer?
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
Just to be sure: Have you pushed the "Detect Displays" button in System Preferences>Display ?

I had to hold the OPTION key down to make that button appear under Display Preferences. Tried that, but clicking "Detect Displays" does nothing.
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
Anyone else have an idea what's going on? I'm really frustrated right now. I have a wonderful 21" secondary monitor mounted in my work space that apparently I can't use with this $2000+ machine since the Thunderbolt ports are the only video out ports on it.

What else can I try that I haven't already done? I also did a permissions repair last night, but the TB ports are still not working.

:Angry:
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
Have you contacted Apple? Called them? Gone to an Apple Store? Used the contact info on their web site?

No. Last time I did that, they were not helpful in diagnosing the issue, and their solution was to send me another of the same thing, which obviously is not going to happen in this case, as I bought it over a year ago and do not have Apple Care. Thus, I am trying to see if anyone here can suggest I try anything else before I assume the ports are shot and pay hundreds of dollars for repairs and in that time be without my primary computer while they try to repair it. I want to be sure I'm not missing anything.

Anyone else here actually have an issue similar to this, and what was the resolution?

Thanks.
 

chscag

Well-known member
Staff member
Admin
Joined
Jan 23, 2008
Messages
65,249
Reaction score
1,830
Points
113
Location
Keller, Texas
Your Mac's Specs
2017 27" iMac, 10.5" iPad Pro, iPhone 8, iPhone 11, iPhone 12 Mini, Numerous iPods, Monterey
The Thunderbolt ports are backward compatible to MiniDisplay Port. Do you have a MDP adapter that you can try? Even a MDP to DVI (assuming your 21" monitor has a DVI input) would work if the ports are OK. Or an MDP to HDMI would likewise work.

I'm finding it hard to believe that a machine a little over a year old lost both its video output ports. I suppose it's possible but not very likely. If both ports are really defective, you may be looking at an expensive repair since that will likely require the logic board to be changed out.
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
The Thunderbolt ports are backward compatible to MiniDisplay Port. Do you have a MDP adapter that you can try? Even a MDP to DVI (assuming your 21" monitor has a DVI input) would work if the ports are OK. Or an MDP to HDMI would likewise work.

I'm finding it hard to believe that a machine a little over a year old lost both its video output ports. I suppose it's possible but not very likely. If both ports are really defective, you may be looking at an expensive repair since that will likely require the logic board to be changed out.

I actually do have both a TB-to-VGA and MDP-to-VGA adapter (the monitor also has VGA input). I will try that tonight and let you know the results. Just seems odd that the adapter I have now (TB-to-HDMI) would work on my MBA but not on my iMac.

Thanks for the suggestion!
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
Bad news yet again. Tried using the VGA-Mini Display Port adapter, and still nothing. When I plug the same thing into my Macbook Air, it immediately turns the display on and my desktop appears.

Sigh...

Not sure what I'm going to do now. Attempt to replace the logic board myself to save money or sell this iMac (with the TB issue fully disclosed, of course) at a great loss and buy a new one.

Very disappointed. :(
 

chscag

Well-known member
Staff member
Admin
Joined
Jan 23, 2008
Messages
65,249
Reaction score
1,830
Points
113
Location
Keller, Texas
Your Mac's Specs
2017 27" iMac, 10.5" iPad Pro, iPhone 8, iPhone 11, iPhone 12 Mini, Numerous iPods, Monterey
I would take it to Apple and throw yourself on their mercy... never hurts to ask about repairing it for free since your machine is fairly new. Never can tell, you may just get lucky. We've seen some fantastic customer service stories in our forums. Let's hope yours is the next.
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
(previous post deleted)

Changed my mind, and will not bother seeing about getting the TB ports on the iMac fixed. I have been wanting to get a Mac Mini anyway to dedicate towards music production tasks, and just purchased one. It has HDMI (for monitor) and FW800 (for HD) ports native, so that works out great, and of course it has a TB port too should I need it.

The iMac works great besides the TB ports and I've really enjoyed it. I'll just sell it at a bit more loss than normal down the road (due to non-functioning TB ports) when I upgrade to whatever the "latest and greatest" iMac is a year or two from now. For now, it is still my primary computer, and I don't really need a second monitor for anything other than music related stuff (my secondary monitor is mounted to the side of the desk, and swings over my stage piano...now it will be the primary monitor for the Mac Mini).
 
Last edited:
Joined
Nov 16, 2015
Messages
1
Reaction score
0
Points
1
I didn't ever used my thunderbolt ports till last week.
I bought a OWC thunderbolt 2 dock last week and it seemed not working.
So I tested it on a other iMac 27" with Mavericks. Then my dock works fine.

I called the support from Apple and after these tasks requested by Apple, my thunderbold ports do no longer work.
- Bought a new thunderbolt cable on a apple store
- Reset SMC
- Reset NVRAM
- Install El Capitan from scratch

So I am really disappointed.
Do you have an idea to solve my problem ?
 

chscag

Well-known member
Staff member
Admin
Joined
Jan 23, 2008
Messages
65,249
Reaction score
1,830
Points
113
Location
Keller, Texas
Your Mac's Specs
2017 27" iMac, 10.5" iPad Pro, iPhone 8, iPhone 11, iPhone 12 Mini, Numerous iPods, Monterey
Same reply to you as above. Take the machine to Apple and have them run diagnostics on it and get an estimate for repair if the ports are indeed dead. There's nothing you can do by yourself unless you are skilled enough to change out the logic board (assuming that's the problem).
 
Joined
Mar 23, 2013
Messages
187
Reaction score
5
Points
18
Location
near Versailles
Your Mac's Specs
2021iMac M1 Monterey;2019 iMac 21.5 Monterey;2017MB 12"Mojave, 2iPhone12, AW2 + AW6
Thunderbolt + HDMI to monitor works with MacBook, not with iMac

Hello,

I had a similar problem as GraceGuitars: thunderbolt-to-HDMI cable from my mid-2011 iMac 12.1 (A1311) did not detect my Samsung external monitor. Combination worked with my MacBook Air and another, more recent iMac.

The solution - discovered this morning after trying everything yesterday : push the Thunderbolt plug fully into the computer port. I know, it's the first advice on the list, but the port on the older iMac was 'sticky' and I had to apply more pressure. Maybe the first T-bolt ports were not as good as later ones? Or I just got one that was slightly off-spec?

Anyway, a relief.
 
Last edited:
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
Resurrecting this thread I started long ago. I'm still quite peeved that neither of my thunderbolt ports are working, as it would be nice to have a secondary monitor. I could replace the logic board myself (I've read the ifixit tutorial and have the skill and patience to complete it successfully, but wow what a pain in the rear) for about $550 in parts/tools. It's either that or taking a gigantic hit in selling it and buying a new iMac. Then of course there's taking it to the Apple store and paying a lot more, I'm sure. Basically, there are no pleasant options, and it's an issue of picking the "lesser of multiple evils."

However, my question is, is there a sure-fire way to determine for a fact that the ports themselves are the issue without taking the iMac to the Apple Store? I ran the Apple Hardware Test (with the extensive testing option checked) and it said "no trouble found." The ports are clean and dust free. I've even tried AMACL's suggesting of pushing the plug really firmly, but absolutely nothing works.
 

Slydude

Well-known member
Staff member
Moderator
Joined
Nov 15, 2009
Messages
16,717
Reaction score
603
Points
113
Location
North Louisiana, USA
Your Mac's Specs
2.8 GHz 2008 MacBook Pro 10.11, 8 GB mem, iPhone 12 Pro Max, 2015 iMac 16 GB Big Sur
Have you considered connecting the additional monitor using one of these. I used a device similar to the first one several years ago and it worked fairly will. IIRC at that tines there were some issues with the device I used not really working well if I tried to use software that needed Open GL. support. It might be worth checking into them further and the OWC gang has good support.
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
Wow, thanks! I didn't know it was even possible to get a video signal through USB. I just might give that a try.

I'd still like to know, though, about a sure-fired way to diagnose the issue with my thunderbolt ports (if what I've done so far has not already proven what it is), in light of future resale.
 

Slydude

Well-known member
Staff member
Moderator
Joined
Nov 15, 2009
Messages
16,717
Reaction score
603
Points
113
Location
North Louisiana, USA
Your Mac's Specs
2.8 GHz 2008 MacBook Pro 10.11, 8 GB mem, iPhone 12 Pro Max, 2015 iMac 16 GB Big Sur
You're welcome. Hope that helps.

If you decide to go with that USB device keep us posted on how it works. I'd like to know how much such devices have improved since the last time I used one. We've had a few members recently that i've suggested something like this to as a possible option.
 
OP
usagora
Joined
Jul 6, 2008
Messages
857
Reaction score
52
Points
28
You're welcome. Hope that helps.

If you decide to go with that USB device keep us posted on how it works. I'd like to know how much such devices have improved since the last time I used one. We've had a few members recently that i've suggested something like this to as a possible option.

I will. I did order it and it should be here Friday.
 

Shop Amazon


Shop for your Apple, Mac, iPhone and other computer products on Amazon.
We are a participant in the Amazon Services LLC Associates Program, an affiliate program designed to provide a means for us to earn fees by linking to Amazon and affiliated sites.
Top