⟐ Answered April 06, 2024 at 3:48 MST

I have an LED cinema display 24" from 2009, I have excatly the problem that the screen blanks out after a 1 sec flash of the image (probably LED driver signal turns down). I was about to try the bypass solution above for the 3.3V drive input, but then wanted to ask first if the same backlight strip probem problem could be on my LED Display as well, because I would not want to loose the dispay dimming possibility.

update:

So I did take the LG LCD panel apart in search for the notorius LED Strip, see pictures:

Taking the LCD apart:

The LCD frame,

The Backlight panel,

The plastic frame,

The glass of the panel,

The back plate,

Finally getting down to the LED Strip

So I did resolder the LED connector (just added some solder to it and re-heated the 5 pins again thoroughly), but my problem still persists, the LED stripe only flashes quick at connection display port connection time. I am considering of doing some logic measurements tonight with my oscilloscope for the LED driver, but the willi fix for bypassing the 3.3V is starting to sound tempting (still trying to find out the real reason for this failure, and I have to admit that the LED stripe fault sounds more plausible to me due to the drive signal LED shutdown after one second flash.

@io nut

I made some advancements with the display but the reason for the fault is still unclear.

All of a sudden the LEDs decided to turn on again.

I am convinced that it has something to do with the horizontal positioning of my setup. While lit I quickly checked the LEDs and realised that Led nr. 27,30,40 and 60 are out. Next day when I started the display the background lighting did not lit again.

I figured it might have something to do with grounding and tried out connecting the displayport without the USB cable. No effect the LEDs turn on with or without the other USB connector and/or the Powerconnector. I realised that the LED cinema display brightness can not be adjusted without the USB cable connected to the my macbook pro.

LED illumination pattern 2/3 Leds.

LED illumination pattern every third LED

So after all the MODs my display is running again. Eventually I ended up only changing 9 capacitors (3 pcs of each of the black ones in the pic, the orange ones I still have originals) on the powersupply,

and resoldering the LED stripe connector,

in addition I assembled and reassembled the display several times (loose connectors).

So Im still not convinced about the source of the fault and Im now testing the display for a week, lets see if it actually stays on.

My Apple LED Cinema Display 24" is still up and running.

Unfortunately I have to report that my LED cinema display died again after one month of fluent usage. So Im back to square zero. :!

I decided to try out if my display runs and it seems to run again :). So lets see for how long, but I am suspecting some sort of capacitor voltages that are incorrect due to capacitor ageing.

⟐ Answer edited January 22, 2025 at 7:35 MST

Please help.

⟐ Commented October 30, 2020 at 13:56 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

From here, I don't know how to proceed troubleshooting this problem. It's always evading my attempt to fix it. The best way to troubleshoot this problem would be to temporarily swap identical model components to isolate what is the source of the problem. But I'm living in an area where nobody has a ACD. I've tried bartering with ACD sellers on online marketplaces to no luck. There are six main physical components inside the monitor that are culprits, replacing each on the off-chance would cost a collective ~€300 if I was unlucky.

Images: http://imgur.com/a/09iOx

Dan,

I've read the service manual carefully several times but I can find no solution and I've read every answer to the backlight issue on fixit but find no solution.

I've taken apart and reassembled every component inside the monitor with the exception of the main driver cable leading directly into the monitor. It was covered with weird silver tape (electrical tape?) that had to be peeled back. But I haven't had the guts to attempt to remove the cable from the slot, as it doesn't seem to want to come out. Does anyone know how to remove this cable?

Images: http://imgur.com/a/i3JUs

I have an update 13 months since my last post. The brightness in my display eventually gave out entirely and just didn't boot up at all when I powered on the processor. But then to my surprise the processor also stopped booting! Which implies the problem was with the processor all along.

Anyway, I bought a replacement graphics card and PSU individually, and neither part solved the issue. I cleaned the inside thoroughly and made sure everything is connected and such.

I am not done with the problem. I have not yet found a solution. My current focus is on the backplane board as I have ruled out almost everything else.

Occasionally the processor boots after an attempt to power up, with the display flickering for a moment and then going black.

⟐ Answer edited January 22, 2025 at 7:37 MST

I'm posting some pics. Any suggestions?

Thanks!

⟐ Answered September 21, 2023 at 12:44 MST

⟐ Commented January 24, 2020 at 15:27 MST

My cinema display started smelling weird and then shut down. I opened it and found the problem to be a burned spot on the logic board. No problem I'll just replace the logic board and then I can use it again.

So I was browsing for a new board when I saw a dutch thread with someones logic board also burned. But the weird thing is that the burn is at the exact same place.

Does anyone have had a problem with a burned board?

⟐ Commented November 03, 2015 at 4:53 MST

After some time (more than 6years of almost everyday usage that's not bad) my display got some difficulties to stay "awake", and then goes definitely black.

First I though, after some deep reseach on internet that it was the PWM module on the main board. (I could see a perfect image on the dark with a flash light.) So I cut some wire and short circuit the "power balun" as they said that energize the back panel. You find a lot of info on google. But.... this was not this. ( this is not for everyone)

Too bad I did it for nothing.

They come the idea, to do another try with a probabilist failure approach : change as much as possible capacitor in the power supply ( you can still find this power supply for sale on Internet type PA-2201-02A 661-4821 or A1267 on Ali express even mother board for 80-150$ each)

Then I ordered, same parts characteristics mostly, a couple of 1uF 450v, a combination of 400-450v 39-120uF and 10uF/50v + 22uF 50v.

Did it on Ali Express to test the approach fix a chinese pb with chinese supply. Intellectually, this was an interesting idea ?

Found some componant that was reasonably priced. ( 30 - 40 days of shipping but arrived )

typically : I bought this lot and une one of the capacitor to repair.

https://fr.aliexpress.com/item/10pcs-120...

It is just a little to large but the power supply still fit in place. ( I just did not put on the screw )

Then for about a budget of $11 + about approx $15 for the other capa the display when on again.

You have then a lot of spare for other device.

Basically the power supply is well design, very few capacitors, the only difficulties is the board is RHOS

so tin takes more time to be unsolder.

My tips to helps I add a traditional lead solder to lower the fusion point of the mix.

I hope this helps other.

And for once, thank Apple for a reparable design.

⟐ Commented October 09, 2017 at 16:59 MST

Thanks.

⟐ Commented June 16, 2020 at 18:39 MST

⟐ Answered June 05, 2015 at 11:01 MST

I've a problem with my 24" LED cinema display. The display is constantly switching on and off. I've used the Apple Technician Guide to check out whats wrong. I was going step by step trough it. What i found out is:

The volltage between TP11 and GND is not stable. It moves constantly between 22.7 - 23.2 VDC.

Also the connector cable voltage (Pin 1 and GND) from the power supplay is moving constantly between 14.3 - 14.8 VDC.

All other voltages are stable and in the needed range. It looks like the power supply is somehow not working correct.

On the power supply unit its is no damaged part or short visible.

So before ordering a new power supply for 250$ from US to Switzerland my questions:

- Can somenone confirm that most likely the power supply has to be replaced?

- Is it possible to check and maybe repair the power supply itself?

Thank you very much in advance for any help!

BR

Marcel

⟐ Commented October 26, 2017 at 10:33 MST

Is there any one who successfully done it?

Thanks in advance,

⟐ Commented October 05, 2021 at 9:48 MST

⟐ Answered January 24, 2018 at 15:30 MST

Can I divert the 27-inch part number 922-9743 or 922-9362?

⟐ Answered January 18, 2018 at 9:23 MST

⟐ Answer accepted April 28, 2015 at 19:16 MST

i have a problem:

My Apple Cinema Display won't turn on again.

The USB and iSight Camera does NOT work.

It won't be recognized by my mac (nothing happens at the Mac-side).

It still can charge the Mac.

The fan is spinning.

I measured the voltages on the Logic Board an they are all ok (i use the Apple Technicians Guide for help).

All cables are connected and the boards looks like new.

Can anybody please help me?

Sorry for my bad english, i am from Austria.

PS: ich habe das Display-Kabel (das interne) auf Durchgang überprüft und es passt.

Best regards and thanks for helping!

Mike

Update 21.2: Hello, im tested a few things on the logicboard and found something strange.

When iam unplug the cable which goes from the logicboard top to the Panel, i have 24,3 Volt on TP11 and the fan is spinning.

When i plug in the cable an move it slightly, then the fan stops to spinn and i have only 14,8 Volt.

So it looks like the cable is defect, but how can this happens? The cable was never in motion.

And the Mac still dont find the Display, with or without the cable :(

Thanks for help!

I have taken some pictures of the LCD board and the Chips look alright.

Next week i want to measure the voltage with the oscilloscope, maybe the power supply has a defect ELKO which drops the voltage.

⟐ Answer deleted January 13, 2022 at 5:14 MST

⟐ Answer unaccepted March 18, 2024 at 3:29 MST

This is my webcam connector https://drive.google.com/file/d/19FsGzWg...

⟐ Commented December 31, 2022 at 1:01 MST

I have a 24” LED Cinema Display that stopped working properly. The monitor is able to power my laptop, utilize the USB ports with data, sound works, and the iSight camera works. I isolated the issue to the backlight as I shined a light on the screen and I can see my desktop mirrored.

Interestingly, when I first plug in the display while connected to my Macbook Air, the screen will flicker for a split second so I assume that the backlight still works and that is NOT the issue but I am not entirely sure. When the display is on, I do not see a dim glow at the bottom even at the highest brightness.

I opened up the display to make sure the the cables were not pinched or anything and fully connected but I am at a loss right now. I unscrewed the power supply and logic board and didn’t notice any bulging capacitors after doing a very quick glance. I noticed on the power supply board there was a white chalk like substance covered on the left portion of the board and I cleaned it with isopropyl alcohol but didn’t notice anything else.

I was trying to follow a similar guide on this website but I am not sure where to start. Wondering if it could be a capacitor issue, or voltage issue?

Should I just cut my losses and recycle the machine?

Thank you!

⟐ Answer deleted September 01, 2022 at 12:46 MST