Submitted by Pixel Chimp on Tue, 18/09/2012 - 15:39

LED PSU running an Apple Cinema Display

Close up of the supply & power switch

NB: Photos copyright Eroni De Oliveira

A reader sent me some information on replacing the Apple power supply for the Cinema Display. He realised that a 24V ‘LED Strip’ power supply should meet the power requirements for the display.

The power supplies sell for around $20 which is a considerable saving compared to the Apple version around $100 to $200 (depending on usage). He was in the process of testing 2 ‘dead’ displays and was able to exchange parts between them to diagnose the problem for each display…

I ended up fixing one of the monitors by switching CCFLs between them, which confirms my belief that the most common problem among these older units, is related to the backlight bulbs. The other monitor has a cracked LCD display.

Like any fluorescent lamp, as they get old, and darkens it’s extremities, their current consumption changes, triggering protection circuits in the ballast board and/or the logic board, as well as in the external power supply itself. Remember that these bulbs work with high voltage (around 420 Volts) and any small current variation at that level causes a much higher one at lower level, hence the need for protection circuits despite having a 3 Amp fuse at the ballast board. That explains why, sometimes, a more powerful power supply is able to correct it (temporarily nevertheless).

Another issue has to do with the high cost of the original power supplies been, most of times, twice the price of a defective monitor. I decided to use an alternative power supply that cost around $ 20.00 and are very stable and ripple free. They are designed to power LED strips, with an output of 24 Volts, 5 Amps (about 120 Watts). They have others with different specs also. The output voltage can be “fine tuned” to precisely 24.5 Volts; there is a control for that purpose.

The connection is simple: the shield (from the monitor) is grounded along with the ground from the AC line (green wire). The red, from the monitor, goes to the positive and the black to the negative. The “control/protection” from the monitor (center thin wire) I left disconnected. I trust that the 3 Amps. (on the ballast board) should blow, in case the bulbs get really bad.

Ebay LED Power Supply and Alternative Ebay supplies

– Eroni De Oliveira.

The pictures are self explanatory, cut off the Apple power connector from the display and wire the correct outputs from the supply.

It certainly seems like a good solution. With a simple case added to the supply it should keep running for another few years just think about the heat dissipation if you do choose to put it in a case.

Thanks for the info Eroni, I envy your workshop :^)


Alternative PSU for 20” and 23” ACD

Submitted by Anonymous on Fri, 28/09/2012 - 22:20.

Good job, Eroni. As to myself, I’ve used an old Powerbook 65W PSU for testing my 20” ACD.

And yes, nice workshop you have there!

No luck though, Q1 on the motherboard itself is blown. It is an SMD transistor, and nobody seems to be able to identify it…

Even though this comment was

Submitted by Anonymous on Sat, 13/06/2015 - 06:20.

Even though this comment was posted years ago… I’d love to know how you used the 65W Powerbook PSU to power the display!

Fingers crossed…!

Just a guess…

Submitted by Pixel Chimp on Sat, 13/06/2015 - 13:45.

I imagine it was simply used as a test - you would need to rewire or convert the adapter output connector to use with the display.

Some Powerbooks seem to run off 24V, so it may be close enough to see if the display is dead or not. Only the 20” display is 60W so don’t try it with any larger models.

PS for 30” model

Submitted by Anonymous on Wed, 31/10/2012 - 12:10.

The 30” cinema display uses a 150W power supply. Still 24.5v but also 6.1A. Do you think the 2nd power supply, “Universal Regulated Switching AC in DC out Power Supply LED)” will work on this? It shows a range of amps, 2a, 3a, 5a, and 10A. Though I can tell how to adjusting the voltage works in the picture, its not clear to me how amps is set/detmermined for output. 5A would be too little, would 10A be too much?



It might be OK…

Submitted by Pixel Chimp on Wed, 31/10/2012 - 15:43.

I’m not entirely sure, but I think it should be set to 10A, then the display will draw the 6A it needs. The power supply shouldn’t get overloaded since it is running below the 10A setting but there is a risk that the supply could overload the display if the display draws too much current.

FWIW the display Eroni fixed was a 23” model that originally runs from a 90W supply, he used a 5A (about 120W) supply. He does mention that the as the backlights fail they can draw more current so if they start to go bad there is the possibiity blowing the fuse on backlight board.

I will ping Eroni to see if he can add anything.

A bit more info

Submitted by Pixel Chimp on Thu, 01/11/2012 - 02:12.

Eroni kindly replied with some more information…

Hi Drew.

You are absolutely right. As long as the voltage is correct and the current (amps) capacity of the power supply is HIGHER than the consumption (demand), everything should be all right, assuming the monitor has no other problems. Take as an example a car battery that has to provide, let’s say 500 Amps to turn over the engine, when starting. The same battery will light a 1 Amp bulb without damaging it, because it’s voltage is constant.

In the case of David, if his monitor stopped working with it’s original P.S. and is able to function with a more powerful one, I would think it is consuming more current than it’s suppose to. Again, my suspicion, in this case, would be the aging backlight lamps (CCFL). Granted, he may get few more hours out of these lamps but still is, in my opinion, a temporary fix.

Another issue is, as we talked before, is the elimination of that center wire from the monitor, which I believe to be a control line that shuts down the power supply, when the consumption becomes excessive. That is why some people disconnect that wire with a piece of paper and get them going for a while longer, remember ?.

If the lamps get so bad and the current reaches high values, still there is that 3 Amps fuse in the ballast board as the last resort protection agains serious damage.

Take care of yourself, and good luck to David. Remind him to observe correct polarity.


I hope that helps David, please create an account if you reply, I may be able to email you more info. I’d guess the 30” display has a higher rated fuse on the inverter board for the CCFLs.

Just did this for a 30” Apple Cinema Display

Submitted by Anonymous on Sun, 10/02/2013 - 22:42.

Hey guys, great info thanks so much.

I just did this with an Apple Cinema Display 30”. I bought a 24V 150w 6.5A power supply off ebay. This one:

Since the ACD was 6.1A I figure that’s close enough without allowing the current too high.

I am by no means skilled with wiring but Eroni’s instructions were simple and easy. $24 total. I can provide a pic if you want!


Hey that’s great Joel. I’ll

Submitted by Pixel Chimp on Mon, 11/02/2013 - 00:04.

Hey that’s great Joel.

I’ll add the pic to the post if you want to send it. Try the contact form & I’ll get back to you.

It’s good to hear others have resurrected these displays :)

I have an ACD 27”

Submitted by viettrungforum on Sat, 15/06/2013 - 13:29.

Dear Joel,

please send me the pics you did with your ACD 30”. I have ACD 27” and the Supply 24VDC, 10A but I didn’t know how to wiring. I supose that I will cut the MagSafe of ACD 27” then wiring to the supply?

Please send to

Best regards.

The monitors we are fixing

Submitted by Pixel Chimp on Sat, 15/06/2013 - 14:20.

The monitors we are fixing are the older ones without magsafe. I doubt they are failing in the same way as the newer magsafe versions?

This fix may not appy, the wiring is almost certainly different.

Search around, you’ll find the service manual somewhere.

How easy is this?

Submitted by Anonymous on Sun, 04/05/2014 - 05:16.

Hello Joel, my name is Joel as well. I just got a 30’ Cinema Display and the the power supply is bad. Could you send me instructions and a picture of your to my email?

thanks a lot.

Hi Joel#2

Submitted by Pixel Chimp on Sun, 04/05/2014 - 15:47.

I’m not sure that Joel#1 will see this so I’ll try to provide some info…

The power connector should have 3 wires, red, black and grey.

It terminates in the black conector inside the monitor as shown in the first picture at /2011/12/18/apple-23-cinema-display-possible-fix-short-long-short-error/

You have 2 options to hook up to the new LED powersupply.

1. Cut the power connector & rewire onto the black & red wires.

2. Dismantle an Apple power brick, remove the connector & wire the PSU onto that.

This page has a simple diagram of how the connector is wired (see the accepted answer).


24.5V 0V no connection 0V 24.5V
24.5V 0V no connection 0V 24.5V

The pins have duplicate connections, probably because Apple chose such small contact areas for a lot of current.

Hope that helps…

30’’ apple cinema display

Submitted by Anonymous on Sun, 06/07/2014 - 13:58.

Hey Joel. I have a apple display and im trying to do the same thing you did for the power supply. If you could respond to this and help me better understaind this i would appriciate it or if you would like to call me my number is xxx-xxx-xxxx

It’s been a while…

Submitted by Pixel Chimp on Sun, 06/07/2014 - 14:09.

Joel#1 or Joel#2 haven’t responded to the earlier comments, it’s been a few months now.

If you are having issues you can try the contact form to contact me directly. I haven’t used this fix, but I understand how it works.

I’m really unsure what to suggest, it’s just some basic wiring that you need to do to make the LED supply run the display.

P.S. I edited out the phone number - sorry I don’t want other people getting junk calls from numbers on my blog.

Flickering Lines

Submitted by Anonymous on Fri, 11/04/2014 - 05:24.


I have an Apple Cinema Display 30” monitor.

After the monitor runs for a while (a few hours) the screen starts to show horizontal lines on it in random areas. It is odd because if the screen is all white, then I don’t she horizontal lines flickering.

I tried a different video card and same problem.

I am wondering if anyone knows if this might be an indicator of a bad power supply.

Not sure I know what is happening here…

Submitted by Pixel Chimp on Thu, 17/04/2014 - 01:35.

This seems a little odd. The lines must be because of something that is controlling the LCD display. Does it happen on a different Mac? I guess it could be the logic board on the Mac if you used the same one for each graphics card test.

I think as the monitor heats up something expands just enough to open up a loose connection?

I would see what parts of the display case feel hot & try to cool them by blowing air over them with a fan. If you can isolate the issue to one side or region of the display it gives you a good idea where to focus your attention once the case is opened.

From there I would check all the connectors are clean, correctly seated then move on to visually checking all the solder joints. Sadly some of the surface mount components are tough repair without advanced equipment.

Please excuse the vague advice, I haven’t heard of this issue. See if more searching helps…

Good luck

PS for 30” ACD

Submitted by Anonymous on Wed, 25/02/2015 - 00:06.

This thread was very useful for me. Wanted to report that I used the 24V (adjustable to 24.5v) 6.5a MeanWell RS-150-24. It was $24. Working great!

More options?

Submitted by Anonymous on Thu, 11/04/2013 - 17:07.

Sorry to bump an older post, but I was inspired myself by this post and had a possible contribution/question. Would something like this device work as well for the 23 inch model?

Looks like it can offer a max of 24v/5a from the product description. It’s about 10$ more than the ebay unit but I feel it offers more aesthetics for the extra money. I may order one up and test it out on my 23 inch and post the results but thought I would ask if there may be any glaring downsides to using this over the ebay PS?

Thanks again for this informative post!


I’d expect that to

Submitted by Pixel Chimp on Thu, 11/04/2013 - 18:01.

I’d expect that to work.

It has 24V/120W output that should provide the 90W that the 23” display needs. I’d guess it will warm up since it will be operating near the upper end of it’s spec, but it should work.

I think the LED power supplies have a potentiometer to change the voltage, but that supply probably has selector switches, so you may find the voltage is not as adjustable. Just make sure it outputs a clean, stable 24V for the display and check it doesn’t sag too low as the monitor starts up (ideally no noticeable dip in voltage at all unless you have an oscilloscope to measure precisely).

The casing looks like it is all plastic, so you can’t easily ground the display’s power cable shielding. I believe you can hook the shield up to the ground inside the power supply, but that would give you another wire to run to the display. If you leave the shielding ungrounded you may see noise on the display, or the display could cause interference to other items (I think). I’m really unsure how much this will be an issue, and it’s unclear how the supply can be earthed if it only has a 2 pin EU mains input (I know much about the EU/US system). It may support earthed input judging by the photos.

Ideally the PSU would run with an earth/ ground, since the display is metal :)

Could it possible to modify an xbox 360 power brick for this?

Submitted by Anonymous on Mon, 01/07/2013 - 17:39.…


Just select the right tool for the right job.

Submitted by Pixel Chimp on Mon, 01/07/2013 - 18:24.

It really depends on how clever you are & how much you know about electronics.

The supply in your picture has a 12V & a 5V output. Apple Cinema Displays require 24V.

You do the maths, 12 ≠ 24 where I come from.

Spend around $20 - $30 and get the right power supply for the job, or spend a few days working out how to make the Xbox PSU supply twice the voltage by running it through other transformers before discovering the efficiency is reduced & you no longer have enough current to drive the display safely…

It seems like a square peg for a round hole to me, however if you have a big enough hammer, the peg can fit.

Thanks, I will just wait for

Submitted by Anonymous on Tue, 02/07/2013 - 02:41.


I will just wait for the 24V 10A part I ordered on eBay :) Will let you know the result.

By the way, it should mater which wire I connect to the + and -, right? Just make sure the green ground wires connected to ground?

Thanks again

Polarity is really important,

Submitted by Pixel Chimp on Tue, 02/07/2013 - 13:49.

Polarity is really important, if it’s wrong it can destroy the device depending on if it has protection circuits. Use a multimeter to see what the supply outputs.

Apple used standard red & black wiring inside the display connector, with the grey wire as a ‘sense line’ (not ground). The ground should be connected to the cable sheilding according to Eroni’s instructions.

Don’t forget measure twice, cut once :)

Good luck, and let us know how it goes.

Got it working

Submitted by Anonymous on Wed, 03/07/2013 - 00:57.


I finaly got my adapter from ebay. Wired all wires as guided and got my monitor working. One thing though, the screen blinks when I increase brighness to the maximum using the + button on the monitor. That’s not normal, right? I am still happy with the result though.

Thanks again!

The blinking doesn’t sound

Submitted by Pixel Chimp on Wed, 03/07/2013 - 01:13.

The blinking doesn’t sound right, check the service manual for trouble shooting. I may be tempted to open the display & check everything is connected correctly. Mine just fades up as the brightness is increased.

Have you made sure the output is 24V? If the power supply is adjustable it would be worth checking it is outputting the correct voltage.

Good job on getting it working again :)

Any chance for more detail?

Submitted by Anonymous on Mon, 29/07/2013 - 17:05.

Hey there! First off, THANK you for this. I may actually get to continue using my ACD 23” without the need to plop down over $150 for a new power adapter. However, I want to make sure I do this right. Do you have, or know of where there may be, a more detailed step by step for this procedure? Super appreciate it, and thank you again!

I’m afraid I don’t know of

Submitted by Pixel Chimp on Mon, 29/07/2013 - 17:39.

I’m afraid I don’t know of any other places that troubleshoot Apple displays like this. I mostly gleaned what I know from other forums via some internet searching. Eroni contacted me with the PSU replacement info, I thought it would help to post it.

The ‘service source manual’ is the closet thing to a repair manual if you can find it. It troubleshoots major components like entire pcb boards, or power supplies etc. Apple expect service engineers to replace entire modules not components (it keeps repair time and costs down).

It is the best place to start, since it lists disassembly instructions and required tools and techniques. Otherwise try

If you are not familiar with electronics read up on handling power supplies, it isn’t difficult if you use some common sense :)

Thank you, wow, quick reply.

Submitted by Anonymous on Tue, 30/07/2013 - 16:10.

Thank you, wow, quick reply. You are much better at keeping your blog up to date than I am. But, yes, thanks, and for all you’ve put up on the apple discussion boards as well. One last quick question. I see in the pic there is an on/off switch attached to the power supply. I’m assuming that didn’t come with the power supply. Do they not have an on/off on them, or is it just for convenience? Cheers!

I’d guess the PSU’s dont have

Submitted by Pixel Chimp on Tue, 30/07/2013 - 22:25.

I’d guess the PSU’s dont have built in power switches. I don’t think it’s an issue since the Apple ones don’t have them either. It’s probably there to save wear and tear on the plug.

Personally I get paranoid about devices I make & like to turn them of overnight if possible, at least untill I know they work as expected :)

Good luck with your display.

Super Thank You

Submitted by Anonymous on Thu, 08/08/2013 - 01:37.

Hey, just had to thanks again, what a treat! My monitor is alive!!! FYI to others who knew as little as I did:

1. You can google an image of all the icons for the power supply terminals. Lets you know what they all mean.

2. For the power cord, just get your hot and neutral correct. Look for a W next to one of the prongs, or one side of the cable will have ridges, google that for more info.

3. You can get these power supplies on Amazon. Same price. When I looked on eBay, they were all shipping from China. Amazon was a bit faster.

4. Now the boss here reminds you to switch the power to 110v. Don’t forget! You’ll need to remove the mesh grating to get to that switch. There is a sticker on the mesh grating pointing to where it is. Oh, I am so happy! Thank you thank you thank you!!!!


Submitted by Anonymous on Wed, 09/10/2013 - 18:30.

Hey there again,

So, all is still working well, can’t thank you enough. So I do notice now and then a bit of a…hmm…how to describe, it is like a flickering. The top 1 inch of the screen will kinda flicker a bit now and then, and the flicker seems like a slight dimming of power.

You had mentioned that these power supplies (I think you did) where good because you could make slight adjustments? I’m wondering if I need to look into that. For now, I’m happy, but if it happens more often in the future, perhaps.

Could you describe how one can make small adjustments to the power flow? Thanks again!

Flickering could be the input

Submitted by Pixel Chimp on Sat, 26/10/2013 - 16:47.

Flickering could be the input power supply, you would need to monitor the input voltage to see if there are any noticable dips as it flickers. You would also need to monitor the input current too to look for similar dips. Be aware that your multimeter must be rated to support the levels you want to monitor.

I would lower the backlight to see if that makes any difference - perhaps the inverter is failing to supply enough power to the cathode backlights?

Otherwise it could be a loose connection internally which is difficult to diagnose (either in the PSU or the display). You may notice a pattern to the behaviour e.g. if it only happens when the monitor or supply is hot it could be something that has expanded & opened up a solder joint. Also listen for any sounds from the display, Mac and PSU as it happens - buzzes or squarks are not a good sign.

Another posibility is that there is another device that is causing interference, this can be diagnosed by moving the display & computer onto another part of the power curcuit in the building, I’m not sure how this would only affect the top inch of the display though.

Also you will need to try another computer to rule out the graphics card in the current machine, re-seating the graphics card (if it is a Mac Pro) may help clean any dirty connections.


Submitted by Anonymous on Tue, 05/08/2014 - 19:53.

Been a while, and I wanted to update.

Nearing 1 year since setting this up for my ACD. Still working great. For the first month I would un-plug at night, but I no longer do. So almost 1 year of constant running.

I still get some “flicker” at the top of the monitor now and then. Never got a better voltmeter to test it out. It comes and goes. I just started paying attention to it agian lately. I’m going to try to notice if it is realted to when the house is pulling a lot of electricity (when the central AC turns on for example)

But I wanted to thank you again.

Thanks for the feedback

Submitted by Pixel Chimp on Wed, 13/08/2014 - 04:49.

It’s good to hear these are still functioning with this fix.

You may want to look at a UPS or filter if you have a poor mains supply, it may help filter out any noise etc.


Submitted by Anonymous on Mon, 02/09/2013 - 18:57.

Can anyone, who has tried this, tell me if the Usb ports are still working after this modification? From what I’ve read the grey cable is the 5V cable for usb.

On the one I fixed it still

Submitted by Pixel Chimp on Mon, 02/09/2013 - 19:50.

On the one I fixed it still worked, but I wasn’t making a new power supply, I replaced a faulty regulator.

The grey cable isn’t 5V it is a ‘sense line’ with a fixed resistance that the display uses to detect if the PSU was intended to power that display. Otherwise a 30 inch display could overheat a PSU intended for a smaller monitor (they have the same connector).

You can test the theory by blocking the center pin - like the ‘jacobean fix’ on the Apple discussions as mentioned in the previous post.

Would this work on a 23” Display

Submitted by Anonymous on Sat, 26/10/2013 - 15:57.

Gino LED Strip Light Switching Power Supply Driver AC 110/220V DC 24V 5A 120W

That seems OK

Submitted by Pixel Chimp on Sat, 26/10/2013 - 16:24.

Probably, if the supply is adjustable you should be able to turn it up to the 24.5V that the display requires.

The LED power supply that Eroni used also is 24V 120W so it should work.

Gino LED Strip

Submitted by Anonymous on Sat, 02/11/2013 - 14:36.

Just to let you guys know, This Gino power supply did work. Plus it was only $18.99…

Hey thats good news, thanks.

Submitted by Pixel Chimp on Sat, 02/11/2013 - 14:42.

Hey thats good news, thanks.

Jeff Reisman’s Blog/Replacement Power Adapter/CD 23”

Submitted by Anonymous on Sat, 23/11/2013 - 12:56.

This blog gives easy instructions (with photos) for hooking up the replacement power adapter.

< for-23-apple.html>


Submitted by Pixel Chimp on Sat, 23/11/2013 - 17:27.

It’s always good to see others doing the same fixes :)

23” psu workaround

Submitted by Anonymous on Sat, 07/12/2013 - 15:01.

Hey there,

Got a PSU 24 variable. All working :) No flicker!

Only gripe is that the PSU ‘whines’. If i adjust the voltage the whine will go up or down in pitch. Is this just ‘coil whine’ from the PSU?

If anyone could shed some light i’d appreciate it :)

Top work

Submitted by Anonymous on Wed, 22/01/2014 - 12:07.

Thanks very much for this guide, I’ll be giving it a go myself. I was just wondering what people are are doing to protect/insulate the live mains (220v) wiring on the PSU?

An option for a A1097 power supply fix?

Submitted by tpmac on Thu, 23/01/2014 - 05:43.

Eroni - Thanks for the post and information.

What do you think of the following approach for addressing a dead Apple Cinema Display 23” power supply while preserving the ability to use the USB/Firewire ports on the back of the monitor and avoiding cutting the power connector off the monitor cable:

1. Crack open the A1097 power supply brick and remove the guts from the case.

2. Dismantle the innards and:

     a) isolate/separate the A/C plug and wires that are connected to it 


     b) isolate/separate the small circuit board with a resistor attached to the outlet for the power to the monitor (small oval outlet) with the wires that are connected to it.

3. With the shell of the A1097 stripped of everything, reinstall the above two items into the shell

4. Connect red wire extensions to the live leads of each live wire and connect black wire extensions to each of the neutral wires on the components that have been reinstalled in the shell.

5. Drill a hole in the side of the shell/case of the powe supply that is large enough for the wires to exit.

6. Label the wires and so as not to confuse the A/C and D/C sides and feed them through the hole.

7. Seal the case.

8. Connect the A/C wires to the new switching power supply: red connects to “L” and black connect to “N”

9. Connect the D/C wires to the new switching power supply:

red connects to “V+” and black connects to “COM”

**note there is no wire connected to the ground on the new switching power supply, but there is a ground wire that runs from the A/C outlet ground post to the small circuit board that the monitor power cable connects to on the inside of the hollowed out former A1097.

Do you think this is a workable configuration?

Plan B is, of course, doing as you described. I’d really like to have those monitor ports available though…if possible withoug spending $200 for a used A1097.

I think that’s OK…

Submitted by Pixel Chimp on Sat, 25/01/2014 - 02:11.

I think that makes sense, you are basically aiming to reuse the existing monitor power connector from the Apple PSU.

See if you can find photos of the internals if you are not already inside the case, some of Apple’s components are difficult to solder by hand.

I’m a little unclear about what you are hooking it up to so long as it’s able to provide the 24V/5A cleanly it should be OK, good luck.

“solution” specifics

Submitted by tpmac on Sun, 26/01/2014 - 04:45.

Thanks for the feedback!

I will be connecting a Cinema Display HD 23” with a Mean Well Switching Power Supply NES-150-24 (output +24V/6.5A).

Yes, the idea is to reuse that existing monitor connection from the original PSU and avoid having to cut the wires on the monitor while, hopefully, keeping the USB ports on the monitor working.

I’ve got the PSU open, the pieces needed for the new “solution” rewired, the new power supply ordered and my multi-tester readu to go. If the new PSU arrives on Tuesday as promised, I’ll be giving it a try then and will circle back and post the results.

It worked, with a catch…

Submitted by Anonymous on Wed, 29/01/2014 - 21:46.

So, after salvaging the A/C part of the original Apple PSU along with he D/C circuit board with power connector and wiring it to the new 24V/5A power supply, I got the monitor and USB ports on it to work. It wasn’t, however, without a hitch.

The hitch was that I had also to cover the middle pin on both sides of the D/C power line going to the monitor with tape to prevent them from making contact.

That method was described in this youtube video:

So the combination of reusing parts from the original, getting a new PSU and taping a couple of connections has got me up and running very cost effectively with a monitor that still looks great!

Thanks for sharing the information such that I could get this working!


Hey, that sounds like good

Submitted by Pixel Chimp on Wed, 29/01/2014 - 21:50.

Hey, that sounds like good news.

Good job :^)

Power supply

Submitted by Anonymous on Tue, 11/02/2014 - 23:07.

Thanks for your post.

However, please remove that power supply listed in your fix. It is an absolute garbage, cheapo knockoff PSU and it looks like it was designed by a 2 year old. I just got one DOA from that seller. I wish I never purchased it.

Suggest getting a reputable PSU from meanwell, lambda, emerson, or ANY company that will actually give you a datasheet. I wish I thought a bit more before just blindly clicking your link.

Sorry you had a bad

Submitted by Pixel Chimp on Wed, 12/02/2014 - 18:05.

Sorry you had a bad experience with the PSU. Eroni managed to get it working.

which power supply to use

Submitted by Anonymous on Fri, 01/01/2016 - 01:15.

I’d echo the comment about the PS specified in the link to be poor quality. Mine died after a few months.

I built another with a Meanwell RS-150-24 (available from, among others) and it has been very reliable. And only slightly more expensive than the eBay one.

Up and running

Submitted by Anonymous on Wed, 12/02/2014 - 15:48.

I finally got around to sorting this today, it was a bit daunting cutting the plug off a screen I’d bought on Ebay without being able to test but it works a treat. The first time I turned it on the screen wouldn’t stay on without keeping my finger on the power button (nearly crapped my pants) but I knocked it off at the wall and tried again and it’s perfect. I’ve used a well drilled sandwich/tupperware box as case for a bit of added peace of mind. Thanks for the guide!

Fixed my trusty old 23” Cinema Display

Submitted by johnsaxon on Sat, 22/03/2014 - 03:02.

Thanks for this great post! I ordered the PSU from eBay for $18.95 including shipping and got it wired up in just a few minutes. My display now works perfectly.

I broke open the old Mac power supply brick so that I could use the connectors. The AC power connector helpfully has “L” and “N” marked on the two power wires so you can just hook those to the new box. The proprietary display connector has a red and black wire and also a ground wire over to one side of the attached circuit board. I connected the ground wire from the AC connector and this ground wire to the ground post on the new PSU, hooked up red to V+ and black to V-, changed the input voltage on the new box to 110 and I was good to go.

USB ports seem to work fine.

You saved me from having to pay $100 to 175 for a new Apple PSU or, god forbid, having to buy a new non-apple display.

That’s great

Submitted by Pixel Chimp on Mon, 24/03/2014 - 17:53.

Thanks for the info, recycling the PSU conectors seems like a good idea to me too :)

I would like to share.

Submitted by Anonymous on Wed, 16/04/2014 - 03:22.

Information perposes only etc…

This is NOT for the faint of heart.

A source for a supply is the HP LaserJet 4 and probaly any in that family that uses the SanKen Model no. RG5-031, or similar variants. I found the 24v on pin 3 of the big connector. Ground or negative on pins 4,5 ,and 6. Pins 1 and 2 are 5v.

I think the important thing here is the presence fo the 24v fan under the grate that is above the controls and display.

Bash the grate open, lift the metal tab and confirm the 24v mark on the fan. If it is there then rip off the right plastic panel. There it is at the bottom! This should confirm that you have a 24v sourse from the P/S. Question everything, grab your multi meter!


There is a HIGH voltage plug on ent side near the AC in plug!

Thank you for all the information here. I hope my contribution helps someone.

Mica P.F.

p.s. I know my spelling and grammer can be atrcious. :-)

Thanks for the info

Submitted by Pixel Chimp on Thu, 17/04/2014 - 01:21.

I guess someone out there may have a dead Apple display & a HP printer to hack up. So long as the specs match up it should be OK I guess…


30” ACD - psu is now clicking

Submitted by Anonymous on Sat, 21/06/2014 - 16:47.


I hope there’s still interest here and someone can point me in the right direction.

I acquired a 30” Apple Cinema Display that was missing a power adapter brick, and based mainly on the info in this thread, I bought a 24v 8.5A 150W power supply from ebay and wired it up. Everything worked fine for a few days, but now the psu makes a rapid clicking noise and the monitor won’t power on. Did I fry something?

Did I need to adjust the voltage dial before hooking it up?

I have a basic knowledge of electronics, but I thought I was in the clear, since everything was working fine.


Sorry, that doesn’t sound good

Submitted by Pixel Chimp on Sat, 21/06/2014 - 17:27.

It would have been wise to check that the voltage was correct before running for an extended period.

Do you have a multimeter?

I suspect you will need to measure the output of the PSU to see if it is now failing to provide 24.5v. 150W should have been enough for a 30” display but I guess it’s possible that the display drew more current & maybe overloaded the supply?

Turn the PSU off, disconnect everyting & let it cool. If you are lucky there may be a thermal fuse that resets. See if you can see the specification sheet for that model of supply, they are confusing, but eventually they can yeild useful info.

Thanks a bunch!

Submitted by Anonymous on Fri, 27/06/2014 - 23:17.

I really wanted to replace my mismatched 22” displays with a couple of Apple Cinema Displays, since I have a Mac Pro.

I was trying to understand why I saw all sorts of displays for sale with no power supplies, so I did some searching and came across your blog.

Being an electronics person, I had no problem locating a 10A 24VDC switching power supply which I am now using to power my two 23” ACDs purchased from a computer salvage vendor on eBay.

Total cost: $230.

Total satisfaction.

Thank you!


Submitted by Pixel Chimp on Sat, 28/06/2014 - 12:12.

No problem.

This was Eroni’s idea, it’s great to know it is working for you too.

Good luck with it & you are most welcome.

30” apple cinema display

Submitted by Anonymous on Sun, 03/08/2014 - 20:59.

hello for the people that have made this work on a 30” apple cinema display and its been continuously working with no problems please tell me the specific power supply and or laptop power supply if used you used please include full specs on power supply and and time in use with no problems and any thing that would be helpful to know while or before the operation in reference to the 30” apple cinema display this would be helpful to me and others as i have 2 that need power supplies and the information I’ve found online so far is for the 20” and 23” as far as giving conformation it worked on those size displays and continues to work i can not find this for the 30” with conformation of working continuously and specific specifications of adapters used so if you can please help by provide your experience and knowledge and it will be very helpful and appreciated by me and others thanks

Please take a look at the

Submitted by Pixel Chimp on Sun, 03/08/2014 - 21:32.

Please take a look at the links in the post.

There are LED power supplies listed, you will need to compare it to the original supply - e.g. you will need a supply capable of 150W (minimum) at 24V.

PS for 30” ACD

Submitted by Anonymous on Sun, 22/03/2015 - 13:30.

This PS has been working for me…..

30” display internal power socket

Submitted by Anonymous on Thu, 16/10/2014 - 17:48.

I would like to try and do this with the 30” version of the display. I have already opened the display and rather than cutting off the end of the cable I would ideally like to connect the power supply to the internal socket of the board. From what I have read when you cut the cable you have a red, grey and black wire, however internally I can see 5 wires, 4 black and one thin greay wire in the middle. Does anybody know how I should connect these to the power supply? It might be worth noting that I am in the UK in case there are any differences. Thanks!

Alternative power supply for 30 inch cinema HD display – (150 wa

Submitted by Anonymous on Wed, 18/03/2015 - 20:08.

I purchase 24-volt DC 20 Amps power supply (china made), and I fixed it as you say.

It’s amazing, I save lot of money plus I put 20 Amps power supply with thermal sensor fan. I am really thank full to you.

Abul Faiz


Submitted by Anonymous on Sat, 13/06/2015 - 07:38.

Does the Voltage need to be 24.5V or is just 24V ok? Lots of people seem to just be using 24V PSUs, however the Apple website lists the supply requirement as 24.5V. Will running just 24V kill the screen?

Thanks in advance

Eroni’s supply was tweaked to output 24.5V

Submitted by Pixel Chimp on Sat, 13/06/2015 - 13:54.

Re read the original post, Eroni said that the supply was setup to output 24.5V. Others are apparently having sucess with 24V, but sticking to the original spec is the best thing you can do.

I suspect 24V may be close enough, however some power supplies can ‘sag’ and fail to output continously. I think you will be safer if the PSU can output 24.5V when under load, there is less chance of causing the display to stop working.

The voltages within the display are stepped up to be high voltage for the backlight, the input voltage & current needs to be within a range otherwise the inverter won’t work, you’d get a different flashing error code for that.

If you are not sure seek out a replacement Apple supply, stay safe :)

High Pitched Sound from Converter

Submitted by Anonymous on Tue, 08/09/2015 - 22:23.

Thank you for this great tip.

I bought the 24v 5a 120W converter (…) to use with an Apple 23” Cinema Display, got it connected and working. However I hear a high pitched noise coming from the converter whenever I raise the brightness all the way on the display. What’s the noise and is there a way to stop the noise? Thank you.

Sorry I don’t know what would

Submitted by Pixel Chimp on Wed, 09/09/2015 - 19:06.

Sorry I don’t know what would cause that high pitched sound.

You should get up close to the monitor and to the power supply to be certain where the sound is coming from.

The power supply will use components that operate at a high frequency, sometimes a solder joint or collection of components can resonate making noise. If the power supply is making the noise I would contact the vendor & return it or enquire if it is considered ‘normal’.

The display also has a high voltage inverter inside which powers the cathode backlights these can also squeal for similar reasons. The noise may be a sign that the cathodes or inverter are failing - the fact your older Apple PSU no longer works also points towards similar issues, as the lamps fail they require more current which the PSU was never made to supply.

p.s. I personally did not use this repair, it was another reader so my knowledge of these supplies is limited.

can’t get supply for 30” ACD to work

Submitted by Anonymous on Fri, 01/01/2016 - 01:26.

I am trying to build a power supply for a 30” Apple Cinema Display. I’ve actually tried one that I built (and worked well) for a 23” model, but it will not work with the 30” one; instead, the pilot light blinks in the repeating “short-long-short” error code which indicates the wrong supply. I used a Meanwell LRS-150-24, which should supply (barely) the current required by the 30”; I’ve measured the output voltage of the PS and it is not sagging (below 24.5v) so I don’t think that’s the problem. I wonder if it has something to do with the center wire (on the connector) ? I have salvaged a connector from a dead 23” brick, and on it I connected the center wire to GND. I tried disconnecting it completely, but still no luck.

I guess it’s possible that

Submitted by Pixel Chimp on Sat, 02/01/2016 - 21:45.

I guess it’s possible that the same 3.3V regulator that causes the other models to show the ‘short-long-short’ error code could be causing your issue. See another page on this site…

Another thing to consider is that the power supply needs to produce a sufficient current, not just sufficient voltage. An underpowered supply may cause the display to fail to work but I don’t know if it would cause this error code.

The center pin on the supply is actually for telling the display what supply is connected, other people would use the ‘center pin hack’ to cover the pin to fool the display into thinking it was a more powerful supply. To me that suggests you should check that the center pin has infinite resistance, I think the 30” model uses the highest rated PSU.