24" Cinema Display Backlight problem

Your Item 2 may have been the trick for me, I plugged an apple USB keyboard in to the monitor and powered up, as I know that the separate keyboard brightness keys go to the Display. I immediately hit the F1 lower brightness key and the display magically appeared. It may be running the LED's full out causes some safety circuit to trip. We will how long this lasts....

Hello,

I'm having the exact same problem as most have reported here. I've taken my display apart, checked both the logic and power supply board along with all the cables. And I found that the "liteon pa-2201-02a" capacitor is making "click" like sounds inside. I'm posting a picture with it.

Do you know if there is a possibility of replacing the capacitor on the board? I've tried to search the item online but it doesn't seem to be for sale anyware aside from just buying the whole power supply scheme.

To make it work now, I just have to unplug the mini display port or the power cable few dozen of times (while it flickers the image twice of three times every time) until it works, but at a slightly dimmer light.

Thanks,

Iulian.

Hello everyone,

After a very long struggle with my own A1267, the backlight only flashing when turning it on, and having to plug and replug the monitor, for it to boot up eventually, I've decided to test both the logic board and the power supply unit inside the case. Both worked perfectly (my test was to simply replace them with tested ones which I knew worked flawlessly). Then I replaced TFT display unit, and of course, it worked. I went even more with it as I wanted to know what is the reason for the display to behave as it does.

I dissmantled the fautly TFT display unit piece by piece and when I got to the last part, the led lights, I noticed a very strong burn smell from it, that indicating the fact it was heating over its design limits (maybe?).

I compared the two outside alluminium frames from both my new TFT and the faulty, older one. I then noticed a difference at the bottom side of it, there, the fautly unit has black tape sticked on the "ventilation shafts" preventing the warm air to escape from the approximately 20 led lights enclosed into the frame. I strongly suspect that it is the reason, or at least one of the reasons for the display to get this issues/behavoir.

I am not sure as to if the replacement of the led lights unit will fix the problem, but it is, I think, a good indicator.

As for the black tape on the "ventilation shafts", I think the reason for it, was to preved the black stains appearing over time under the display glass, as so many A1267 users reported having an issue with.

There are a few photos of both the TFT displays I have now, I tried to take the pictures I best as I could.

Regards,

Iulian.

The fautly TFT with the black tape:

The working TFT (as you can see):

Hi Iulian,

I am playing with the idea picking up one of these from a warehouse clearance place. I am wondering if now that it has been about 2 months since you posted if your display with the tape now removed has keep chooching? I guess they has it on for asthetics? the silver vent hole could maybe be seen through the front glass? thanks t

hi Iulian, I was wondering if you could take a moment to please explain how you tested again because I'm not completely sure. This is what you said:

"I've decided to test both the logic board and the power supply unit inside the case. Both worked perfectly (my test was to simply replace them with tested ones which I knew worked flawlessly)."

Do you mean the ones your replaced worked or the old ones worked?

"Then I replaced TFT display unit, and of course, it worked."

Why did you replace the TFT and do you mean the old one or the new one worked?

Thanks

I am having the same problem with my 24" LED cinema display. The screen is completely black, but audio, USB, iSight, and magsafe charging all still work. I've tried plugging the display into a Macbook, and Mac Mini, and a Mac Pro, all with the same results.

I found a service manual online and used a multimeter to check voltages at the various test points on the logic board. The voltages all came up fine. Based on the step by step guide in the service manual, everything seems to point to the LCD panel. I started disassembling the LCD panel and noticed a chip and possibly a diode on the T-con board were fried.

I looked online to see if it would be possible to buy just the T-con board, but it doesn't seem available, and I am not sure how it would even be possible to remove it from the LCD panel. I might just have to buy the whole LCD panel assembly, which is not cheap.

Hi Mikkie,

Yours seems to be the first of such posts related to this problem that I found to have a very thorough approach. My config too is similar to what you have – a 13" MBP (Macbook late 2011), running Yosemite (10.10.1), plugged to a 24" Cinema Display.

I first encountered my blackouts around the same time Apple pushed out the Thunderbolt Display Firmware update v.1.2. I cannot be absolutely sure that there's a correlation here. Just to be sure, I tried my display with a friend's MBP (without the update) and the display had the same problems.

So far what I've been able to determine by trying various things:

1. Turning off the power supply to the display and replugging it after 10-15 seconds brings back the display. But only momentarily. Display goes dark in a minute or two.

2. I stumbled upon another scenario: that of brightness. If I kept the cinema display's brightness set to around the 35% mark, it would work just fine. No issues whatsoever. However, whenever I plug in the display, the default config puts the display on auto-brightness. So in the window of a minute or so i have, i need to set the brightness to the lower mark. Thereafter, the display works just fine endlessly.

I haven't taken to any service centre just yet. I fear they'll employ the take-the-sledgehammer-to-a-nail approach. So, I want to have some understanding of this problem before taking that step. I unfortunately, have no knowledge or possession of the electronic tools.

I'd love to know more about what you've tried, and if there's anything I could try as well..

After reading your post, I was wondering, is there is any chance that employing a "voltage stabiliser" instead of feeding the power directly to the Cinema Display might help?

Thanks,

Anirban

MikkieRSA,

I've researched this issue a little since I have the exact same problem. Charging, iSight, Speakers all work. In the System Preferences you can even see the display being recognized, just no image. Initially I could get it to come on for a few seconds, then it progressed to just flashing briefly when plugged in, now nothing.

It appears most people just opt to replace both the power supply and logic board for the unit. Since they seem to think it's a combined issue. I'm considering just purchasing the logic board first (both parts are roughly the same $130 - $160) so it's a 50/50, if one doesn't work I'll purchase the other and if both don't work I'll just return them for a refund. If I get the logic board to work and if it looks like the logic board has damage like Pie's would you benefit from having a board to play around with and attempt to repair? I know you probably need a good working board as well to compare. So I've provided a link for the parts. They don't specify if it's refurbished or new.

http://www.macpalace.com/661-4823-logic-board-apple-led-cinema-display-24-mb382l l-a1267.html

Hello... I realize that this is an older post, but I thought I'd add my experience to it in case it can help someone down the line.

My symptoms were exactly the same as described in the original post. I followed the suggestion of anirvan_m to power the display off for 10-15 seconds, and I was able to get the monitor back on. Although, now it's slightly dimmer than it was originally. I'm still trying to figure out why, or if it's just slowly burning out, but it's been working fine for about 30 minutes now, other than that.

I'm having the exact same problems as many of you here... 24" Apple LED monitor (but mine is connected to a 2009 27" iMac). For a while the screen would get really light. Unplugging it and plugging it back in solved that for a few days at a time. Then it went completely black. Still has power to the USB ports in the back though.

I found something interesting though - now when I unplug the unit and plug it back in, it stays black.... UNTIL.... I reboot my iMac that the 24" LED is plugged into (with mini displayport). Then it powers up fine and runs fine.... until the iMac goes to sleep and the 24" LED goes black and stays that way.

Does this indicate anything? Power supply? Or logic board? Mine is in excellent cosmetic condition, and I've had it for probably 5 years. I love it and don't want to part with it. Suggestions would be appreciated. Thanks!

Sounds like I've got the same problem. Starting with the non-working black screen, un-plug the mini display port from the laptop and display's power from the wall. Plug in the power then upon plugging back in the laptop the backlight flickers rapidly on and off about 5 times in roughly half a second and then it stays off. By repeating this several times sometimes it is possible for it to stay on. Then it can be fine for weeks (even going off via energy saving) before the issue arrises again.

The other symptom is the capacitors have been squealing loudly for months now.

I have a 27" apple cinema display and having the same backlight problems.

Most of the times that I plug it in my macbook, the screen stays dark with sometimes a flicker. What I found that worked, was to remove the charger and usb cable from my macbook and just plug in the Mini Displayport connector into the macbook. After pulling it in and out for 1 to 10 times, the screen will flicker and turn on and I can use it until the next time that I unplug my macbook.

Sometimes the brightness doesnt seem to be a 100%, and sometimes its very bright, but as long as this screen is working, thats good enough for me. Although I'd like to fix it too

Tried everything but nothing worked until this!!! Thank you, thank you, thank you!!!