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27" display with 2560 x 1440 pixels resolution Thunderbolt & MagSafe cable attachments

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Thunderbolt display cutting out intermittently, possibly heat related?

I've been using my Thunderbolt Display daily for 13 years without any issues—until last week. Suddenly, it started cutting out and not turning back on as if I had unplugged it.

Symptoms

  • The display shuts off randomly, but more frequently when my MacBook (late-2012 Retina) is closed.
  • When closed: The display cuts out every 1–2 minutes or less.
  • When open: It lasts 2–5 minutes before cutting out.
  • If it cuts out while closed, the MacBook screen stays off until I unplug the display.
  • If it cuts out while open, the MacBook screen remains on like normal.
  • Moving the MacBook away from directly under the display significantly reduces the issue.
  • Speakers will continue playing music, peripherals continue charging or maintain connection, macbook remains charging from the TB cable. No interruption when the display cuts.

Troubleshooting

  • Checked, unplugged, and cleaned all cable connections.
  • Updated my OpenCore Legacy Patcher (OCLP) build and patches.
  • Reset NVRAM/PRAM—but I didn’t hear the Thunderbolt Display fan cycle.
  • Noticed the display feels warm.

This makes me wonder if it’s heat-related. Since the issue improves when I move my MacBook away, I’m thinking the Thunderbolt Display’s cooling system might be failing or the heat from the MacBook is affecting it.

Does anyone have insights or similar experiences? Any suggestions on what to check next?

Update (04/23/25)

I've been waiting for a new thunderbolt m-to-m cable, it finally arrived. I plug it in and get nothing, the strange thing is one or two of the times that I attempted connected, the screen on both the mbpr and tb display flashed like it connected but then cut immediately back to mbpr.

The display fires up and works normal with the factory octopus power/tb cable (other than the intermittent cutting issue of course)

I'm lost. Is this new cable bad? I dont have any other TB2 devices to test this.

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Resolved:
I guess I feel a bit dumb, but it turned out to be the cable + a potentially dead/intermittent port. I tried another new cable plugged into the back thunderbolt port and wasnt getting much other than a brief glitch. Decided to open the display to connect the cable at the board and this resolved the issue.

Display has been working for 2-days without issue since connecting the new cable at the board. Rear port is still not responding correctly, but thats ok I never use it and can diag later.

Thanks for the help everyone

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@rbrfd24 this "it started cutting out and not turning back on as if I had unplugged it" and "the screen was off like it lost power" sounds like you maybe starting to have issues with the power supply. I think it's time to open it up and to take a look at the power supply. Use the guides from here Apple Thunderbolt Display to at least get into it. Once there, take a couple of good pictures of the power supply and let's see if we can make out any weak spots. The time is about right for some of the capacitors to start riding off into the sunset. Adding images to an existing question

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OT - If moving the laptops location on one’s desk improves things how would that be a power supply issue? The idea of heat from the laptop a good three inches under wouldn’t offer the display enough heat to set off a power supply issue. But! The TB cable would be more likely the issue and is a common issue.

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danj there is always more that one option, isn't there? I prefer to remaining open minded and trying to narrow things down to troubleshoot an issue. I do not like to go by second and third guessing and trying shotgun approaches but that is just me. I

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If you’re up to it you may want to give the internals a good clean of the dust and debris buildup. A one inch paint brush and a can of canned air is all you need besides the needed tools to open the system up. Follow this guide Apple Thunderbolt Display Fan Replacement in addition there is a known issue with the backlight LEDs string loosing connection due to the Lead free solder chemistry used at this time. Here’s a deeper view into that issue Apple Thunderbolt Display Black Blanking Out Repair to verify the issue when it winks out place a flashlight against the screen at a sharp angle you should still see the faint image of your desktop and its icons. If you do then that points to the backlight either the LED strings or the backlight power logic.

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Apple Thunderbolt Display Fan Replacement

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25 - 35 minutes
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Apple Thunderbolt Display Black Blanking Out Repair

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4 hours

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Thank you for the reply. I will have to pull the display apart over the weekend for a full inspection and cleaning. On the last cutout I used the flashlight technique but there was no image behind the darkness, the screen was off like it lost power. Again it leads me to believe this is an excess heat issue, where my laptop is bleeding hot air directly into the display and its either overloading the fans ability to cool, or its effecting the power supply board. I'll report back what I find

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@rbrfd24 - That’s starting to sound like the cable is worn. Do you often unplug the display taking your laptop?

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@rbrfd24 - let’s give this a try, if you have a spare Thunderbolt cable plug it into one of the displays connection and your systems Thunderbolt port. This works! As TB is a hermaphrodite connection!

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updated original post with a new question. new cable isnt firing the display, while existing cable does

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@rbrfd24 - Not good, did you try the other ports? If they also fail then you have a deeper issue than the combo cable which often fails.

I don't think this is a power supply issue as jumping between the two connections wouldn't react differently, here the main logic board is suspect. Even still this display did suffer from Capacitor Plague. So you should inspect the electrolytic capacitors just the same.

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