⟐ Answer edited March 28, 2026 at 17:42 MST

Photo #1: Screen with yellow line issue.

Photo #2: Original cord has electrical tape on wire. (I bought it like this.)

THANKS!

⟐ Commented March 06, 2026 at 11:21 MST

⟐ Answer edited February 19, 2026 at 16:34 MST

⟐ Answer edited February 10, 2026 at 12:50 MST

Deep in the weeds with this THUNDERBOLT 27" display -I have no screen, and the thunderbolt connection not detected by an external computer, but power is getting to the logic board just fine. Tested the G, 12V, and 24V rails and power is fine on the logic board. When testing the smaller panel test points, fan, usb, etc. works great, but no power at the LCD power panel test points (Just to the left of the circled component in the pic attached). There should be 12v there according to the Technician's manual.

Ok, but there IS 12V right at the circled component on the one leg at the bottom, but 0 volts on either of the other two legs! So I suspect this part has failed.

Now the help! What is this part? Voltage divider or detector? It's labeled with either a "AM K" or "1 AM K" (K is sideways) although the 1 might just be a line indicating directionality? These components are all over the board and always gives voltage readings on all legs, so that's why I suspect this one is bad. Any super smart SMD folks know what this part is?

⟐ Commented January 21, 2026 at 18:21 MST

2009 MacPro 2 x 2.26 Ghz Quad core Intel Xeon / 32 GB memory silver tower (Model No.A1289). 30” Cinema HD Display aluminum monitor with 2560x1600 resolution. Bought new - its a beautiful display and once a primo $5K workstation. I’ve been running OS 10.6.8 on it to continue using some obsolete legacy apps I happen to love. I also own a newer 27" iMac.

From the beginning, this display got very hot, so I’ve always had a small quiet fan blowing across the back of it. Starting years ago, for no apparent reason, the monitor would intermittently go “completely black”, usually after a few hours, while I’m doing nothing more than typing or moving the mouse. And the tiny green light in front bottom right goes out. After a few minutes, it might flicker back on and stay on, but eventually go black again. At first I’d restart the MacPro, which often helped. Then it didn’t help. I asked around, tried zapping PRAM and firmware updates.

Experimenting, I found the oval/racetrack-shaped plug connection (don’t know the proper term) in the 3-way cable that connects the monitor to the “Dual-link DVI” adapter brick (Apple HD Display 150W Power Adapter A1098) may be the problem, because unplugging and replugging it fixes the issue temporarily. But invariably, after some time, the monitor goes black again. As time goes by, I’d unplug/replug this adapter connection plug 3, 4, 5 times a day. Eventually after many mos. of unplugging & replugging, even that won’t get the monitor going again.

So I found a used adapter on eBay ($75+) and replacing it seemed to fix the problem. But after a few months, up to a year, the monitor starts to flicker/go black again. Frustrated, I buy another adapter, which gets the monitor going again, but eventually stops. I did this many times over the past 7 years. At this point, it seems likely I’m buying others’ problem adapters. Now my 5th used adapter no longer works after only 2 months, the plastic plug guard on the cable from the monitor has broken and it looks like replacing the three-way monitor cable is the only way forward.

I’m finally posting this request for help in exasperation. Thanks for reading it all!

Is there a way to confirm what the problem is, that replacing the cable would fix it? (e.g., could it be a logic or power board or graphics card?).

Is a cable still available? How to get the right one? Saw reports the 3 way cable is non-existent

Can I replace it myself without much tech experience? Checked this ifixit guide and viewed this Youtube video and think I could manage but never done anything more than swap in a graphics card and memory.

What I’ve tried:

- Unplugged replugged the cord from the MacPro to the DVI adapter

- Zapped PRAM

- Contacted Apple (“Obsolete hardware and systems aren’t supported”)

- Replaced the DVI adapter brick (5 times in 7 years)

- Asked for help on the Apple forum. Determined that its unlikely a graphics card or firmware issue

- Read numerous forum posts including:

• 27” Cinema Display turns off randomly

• How can I fix my display blacking out intermittently?

• I have a 30 inch Apple Cinema Display that just went blank

• Apple LED Cinema Display 27" LED Panel Replacement

• Apple Cinema HD Display 30" Teardown

- Shopped around for other 30” monitors, like this Dell UltraSharp U3014 But a reviewer states it requires a DVI dual link adapter system to work - which is apparently the same thing causing the issue with my Apple monitor

Heres my current adapter. I've kept the last 2 as well, thinking it may not be the adapters at all, but they are identical to this one. For all its life until only a few weeks ago, the (4-way) cord built into the monitor looked newish, but the plastic casing broke recently after I used a clamp to hold it in place into the adapter in frustration. It still worked for a time even with the guts exposed but admittedly it now looks like this is clearly the current reason for the problem even though thats not necessarily the case. I've cleaned the plug shiny many times over the years - and the hole as well - and that made zero difference, so now the metal is tarnished from constant plugging/unplugging.

Thanks for trying to help me!

Had high hopes posting my question here would lead to getting help to fix my monitor. Anyone?

⟐ Answered January 21, 2026 at 14:07 MST

Thunderbolt Display connected to Mac mini 2018 MacOs 10.15.6 via Thunderbolt adapter to USB-C.

I’m skeptical of the display because no issues to TV but that’s HDMI signal not Thunderbolt. I’ve repaired the A1267 and hoping not to mess with this one.

#2-How hot is too hot for this display? Fan is running.

#3-Should Display USB ports always have constant power when Mac is off? Will not charge phone constanlty

Thanks in advance..

What’s supposed to be connected here?

No extra parts found

⟐ Commented January 10, 2026 at 11:38 MST

*Took out the chip in case I ever find one from a donor board, but would still like to know if it's worth the extra hassle.

I assume this is a power supply issue with how other things being plugged in affect it, and I already tried replacing the logic board which did not fix it. Is there any other ideas on this, where I could look to repair on this power supply board? Thank you in advance!

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?

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.

⟐ Commented November 16, 2025 at 12:16 MST

All blogs read Replace one of the following:

•Power Supply

• Logic Board

• LCD Panel

Since Im getting power Ive ruled out the power supply.

Next, on to the Logic board.

What needs to be checked? Capacitors?

Please confirm the most likey suspects.

Thanks

⟐ Commented October 20, 2025 at 11:55 MST

https://www.amazon.com/LCDOLED-Replaceme...

Is this the same panel as the original? Is this doable to replace myself? I took a 5k iMac apart before to replace a hard drive, which required taking literally every part off, including the display, so I'm pretty comfortable with fixes like that, but not sure how the Studio Display compares.

⟐ Edited by author September 16, 2025 at 7:24 MST

⟐ Answered July 13, 2025 at 20:44 MST

Strangely, even though when the video is not working, my MacBook still recognizes it (in the sense that I can select screen arrangement settings in System Preferences and also move my mouse onto the other screen). Furthermore, the speakers and camera still work when the screen is black.

I have tried resetting PRAM/SMC and tested multiple laptops and the problem persists. I have also tried using an external thunderbolt cable. Finally, I have shined a light on the display when it is dark and I can’t see any faint images.

Two things that sometimes work to “revive” the display are plugging the AC power cable into another outlet or unplugging the AC power cord where it connects to the back of the display and then plugging it back in. I have also noticed that if I accidentally bump the AC cable where it plugs into the back of the display, this can cause the screen to go black.

What is the likely culprit here? I suspect the AC power cable, but perhaps it is a logic board issue? Additionally, if the AC power cable is at fault, where can I find the right model? I don’t want to buy the wrong one by accident and I also want to make sure I buy from a reputable seller.

⟐ Answered July 08, 2025 at 13:49 MST

I am looking for some help with my 6-year old ACD. It works for about 2-3 seconds when turned on, then flickers and dies. This happens regardless of whether it is plugged into my MacBook or Mac Mini.

Using a flashlight, I can still see my desktop on the screen, but it is extremely dark. The other features (MagSafe charger, speakers & iSight) are all working fine.

Going through the questions here, this seems like a pretty common problem, however the answers are conflicting and confusing - some people say the logic board is toast, others say the backlight is dead, and I've even read something about the backlight being part of the logic board (what??) which is faulty.

Can somebody please confirm exactly what is wrong, and the replacement part I'd need to buy? Your help would be greatly appreciated.

Regards

⟐ Commented June 01, 2025 at 11:05 MST

⟐ Commented February 10, 2025 at 5:55 MST

Lightning port to lightning port cable where is it?

⟐ Answered February 09, 2025 at 8:15 MST

got a Cinema Display from a flea market, without its original charger, and cause I love this screen event its very old I bought it, cut off the charger port in the screen, and plugged in a generic psu with 6, 10 and even one for 16a from a 3d printer

the screen works just fine, but sometimes turns off, but by powering it off and on, or unplugging the power cable it would work again for 20min 1 hours even no problem and then do it again, thinking it was the PSU tried different ones same result

lately tried unplugging just an xt60 between the screen and the 24v rail, and same thing, so thought maybe its something to do with something else, there's a third tiny cable in the same thing, just unplugging it and replugging and the screen works again

if anyone have any idea why it might be id really appreciate it very much

thanks a lot

⟐ Answered January 29, 2025 at 11:01 MST