lebungleski

Q: Apple Cinema Display 23" - Blank Screen, "short-long-short" LED code

Hello everyone.
This sounds like something of an epidemic... My Apple Cinema 23" HD Display (bought Dec. 2007) hasn't been turning on after a power outage hit our area last week.

The Computer and Display were OFF when the outage occurred. Everything was plugged into a surge suppressor. Everything ELSE plugged in to the suppressor is fine (including my Mac CPU)... but not the monitor.
It’s not dead-dead…. It’s a blank screen but there IS a morse-code flash on the LED (short-long-short). According to Apple Support’s LED Translation, it SHOULD be something to do with the power adaptor. The adaptor IS correct… a 90 watt… but just in case I bought ANOTHER 90w adaptor brick. I plugged the monitor to the new brick. THE RESULT WAS THE SAME.

I’ve tried power cycling, I’ve tried plugging it into different outlets, I’ve tried connecting to other computers. The same LED result remains.

And, yes, of course, I’ve got no Apple Support, and from what I read in similar posts, outside-the-warranty repairs could hit around $400. I REFUSE!

For now I have a Samsung monitor from Costco. It’s not bad, but it’s not the Apple monitor with its awesome color-fidelity.

I've read some other posts with the same problem (LED blink code and all) elsewhere but haven't got a solid answer.
I wonder… has anyone else incurring this same problem (with the same LED flashing deal) tried to use a 150-WATT adaptor brick? I would try this myself, but I’m currently financially unable (and personally unwilling) to throw more cash at this problem unless I know it’ll fix it.

Mac OS X (10.5.7)

Posted on Jul 18, 2009 7:03 PM

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Q: Apple Cinema Display 23" - Blank Screen, "short-long-short" LED code

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  • by Drew Reece,

    Drew Reece Drew Reece Oct 21, 2013 9:11 AM in response to creativejedi
    Level 5 (7,485 points)
    Notebooks
    Oct 21, 2013 9:11 AM in response to creativejedi

    Apple service technicians don't do individual component repairs on PCB's. They simply see which PCB board is likely to be at fault & then they replace the entire board, if it still fails, move on to the next board or wiring loom, display panel etc. Perhaps the boards are refurbished back at HQ where they have access to complex test & soldering equipment?

     

    Replacing the main board plus a couple of hours work could easily cost $475. Apple also have fixed rates for each job, so they try to eliminate all the paths that can consume hours of work leading to a dead end.

     

    Using this site & a suggestion on ehmac.com I found a 3.3V voltage regulator had failed, I blogged it…

    http://pixelchimp.net/blog/pixel-chimp/apple-23-cinema-display-possible-fix-shor t-long-short-error

     

    The center pin tells the display what rating of PSU is connected, covering it convinces the display it is running off a 150W 30" display supply so it can draw much more current if it needs to do so. Chances are you are still using the standard 90W 23" supply.

     

    I'm no expert & could easily be wrong, however it worked for me, testing the regulator with a multimeter is the clearest way to tell if it could be the issue, but getting into the display is not for the feint of heart.

  • by Guy Hemmings,

    Guy Hemmings Guy Hemmings Oct 31, 2013 4:33 PM in response to Drew Reece
    Level 1 (4 points)
    Oct 31, 2013 4:33 PM in response to Drew Reece

    My 20" Cinema Display failed too, the LED giving the short long short flashing error message with the white LED. I had read on the net of a solution which involved messing about with tiny bits of tape to isolate the centre pin of the connector to the screen, and reckoned that repair would not last more than a few insertions of the connector before it would fail again.

     

    I took apart the power supply by sawing through the shell on the three clear edges carefully so I could then crack it open.

     

    After lifting out the board I removed the two screws holding the internal connector and on turning it upside down noticed that the centre pin was not isolated due to a surface mount resistor connecting it to one of the other terminals. Following the idea of isolating the centre terminal, I desoldered the resistor, reassembled everything and bingo! the screen works perfectly again, and it is a permanent fix.

     

    It appears that JPGs cannot be displayed on the forum, so visit the URL listed for photos of the fix.

     

    http://macs2u.blogspot.co.uk/2013/10/fix-for-apple-cinema-display-power.html

     

    Guy Hemmings

  • by Drew Reece,

    Drew Reece Drew Reece Oct 31, 2013 5:24 PM in response to Guy Hemmings
    Level 5 (7,485 points)
    Notebooks
    Oct 31, 2013 5:24 PM in response to Guy Hemmings

    Congrats,

     

    You have just made the monitor detect that power supply as if it is a 150W model. It will happily try to pull more current than the PSU was rated for. The alternative is to open the display & test a 3.3V regulator & replace it for a few pounds. The regulator seems to fail & cause the sensing circuit to kick in & switch the monitor into the error mode.

     

    The hypothesis is that ageing cold cathode backlights can start to draw more current as they degrade, the main board realizes it is connected to a PSU that is rated for either 65, 90 or 150W via this 'sense line'. It refuses to continue to power up because would be overloading the supply. The 150W model is open circuit - equivalent the mod you just did (and the paper hack).

     

    I believe this is a safety feature you have defeated so take care with this power supply & display.

     

    For what it's worth no one else has reported any deaths yet, maybe I'm just too cautious?

     

    (Apologies to everyone who has heard me say this over & over, I really believe it is not a proper fix and may be unsafe).

  • by Carey Marks,

    Carey Marks Carey Marks Nov 1, 2013 1:23 AM in response to Drew Reece
    Level 1 (15 points)
    Notebooks
    Nov 1, 2013 1:23 AM in response to Drew Reece

    Hi Drew,

    Well I did this about 6/7 months agao. No problems at all, however I notice the PUSU get rather warm. So I keep items off it. Is that indicative of isues would you say?

  • by Guy Hemmings,

    Guy Hemmings Guy Hemmings Nov 1, 2013 1:52 AM in response to Drew Reece
    Level 1 (4 points)
    Nov 1, 2013 1:52 AM in response to Drew Reece

    Hello Drew

     

    To test the concern that the power supply may try to draw more current than it is rated for (65 Watts), I powered the 20" Cinema Display through a wattage meter. At full brightness with a white screen, expecting that to draw the maximum current from the power supply, it drew 53 watts. Allowing for some margin of error in the wattage meter, we still seem to be consuming well below the rated wattage of the 65watt power supply. I expect what's more important is not to attempt to use this modified power supply with one of the larger Cinema Displays, as the protection you mention is no longer present, and they would obviously want to draw more than the 53 watts of my 20".

  • by Drew Reece,

    Drew Reece Drew Reece Nov 2, 2013 4:43 AM in response to Carey Marks
    Level 5 (7,485 points)
    Notebooks
    Nov 2, 2013 4:43 AM in response to Carey Marks

    I really can't say, I have read logical arguments that I tried explaining above about the cold cathodes possibly drawing too much current. Hopefully it is rare & other safety features may prevent accidents or fire, but personally I would be worried about it overheating.

  • by Drew Reece,

    Drew Reece Drew Reece Nov 2, 2013 4:49 AM in response to Guy Hemmings
    Level 5 (7,485 points)
    Notebooks
    Nov 2, 2013 4:49 AM in response to Guy Hemmings

    That sounds accurate to me Guy.

    The backlights are the big current draw, and the voltage is stepped up an awful lot inside the display, so if they want a few more volts it translates to a lot more on the input. So as long as the backlight was up full it should have ability to power it. I suspect Apple over engineer these power supplies, they tend to make solid hardware, however thats what got us here in the first place :^)

  • by bold_seagull,

    bold_seagull bold_seagull Mar 24, 2014 4:17 AM in response to lebungleski
    Level 1 (30 points)
    Mar 24, 2014 4:17 AM in response to lebungleski

    So, 4 years after Jakobean's fix, I can't see anyone posting any diasters with short circuits, fires, electric shocks or any other side effects.

     

    My ACD 23" went off this morning (it's 7 years old now I think), and the Jakobean fix has just worked.

     

    I used a piece of insulation tape folded onto itself, about 1mm wide, and creased into an 'M' into the cable. Monitor now working again.

     

    Was a tricky fix, requiring attempts with paper, plaster, photo paper until I finally got it with the tape.

     

    Hopefully will give me some further great years of service from the monitor.

  • by Jast_DK,

    Jast_DK Jast_DK Mar 24, 2014 5:39 AM in response to bold_seagull
    Level 1 (0 points)
    Mar 24, 2014 5:39 AM in response to bold_seagull

    So, 4 years after Jakobean's fix, I can't see anyone posting any diasters with short circuits, fires, electric shocks or any other side effects.

     

    I can confirm that after 3-4years I still have no trouble using the fix for my ACD 23". No exessive heat from the powersupply as well.

  • by Drew Reece,

    Drew Reece Drew Reece Mar 24, 2014 10:57 AM in response to Jast_DK
    Level 5 (7,485 points)
    Notebooks
    Mar 24, 2014 10:57 AM in response to Jast_DK

    I'm glad it's all still working for you both, despite my protestations against the 'pin hack'

     

    I do recollect seeing a scorched power jack from this method (looked like overloaded pins IMO), but I can't remember if it was posted here.

     

    Good luck, I still use my 23" ACD too

  • by bold_seagull,

    bold_seagull bold_seagull Mar 24, 2014 1:22 PM in response to Drew Reece
    Level 1 (30 points)
    Mar 24, 2014 1:22 PM in response to Drew Reece

    Well, perhaps jakobean was an Apple plant afterall. An out of the blue technical fix and never to be seen on the discussion boards again despite his name being used across the internet as the solution to this problem. Apple obviously can't say stick a bit of paper into the middle prong, but perhaps keeping many loyal users monitors going was worth inventing a discussion board alias to do so.

  • by louis1946,

    louis1946 louis1946 Mar 24, 2014 2:45 PM in response to Jast_DK
    Level 1 (0 points)
    Mar 24, 2014 2:45 PM in response to Jast_DK

    I'm into year three with the pin fix (put a thin strip of electrical tape on mine). No problems.

  • by creativejedi,

    creativejedi creativejedi Mar 24, 2014 3:05 PM in response to bold_seagull
    Level 1 (1 points)
    Mar 24, 2014 3:05 PM in response to bold_seagull

    I'm another believer. About 6 months on my electrical tape so far, no problems to report. Thanks, everyone, forums are great. -- bold_seagull: Interesting theory, I would like to think that Apple is that benevolent.

  • by Drew Reece,

    Drew Reece Drew Reece Mar 24, 2014 3:29 PM in response to bold_seagull
    Level 5 (7,485 points)
    Notebooks
    Mar 24, 2014 3:29 PM in response to bold_seagull

    It may have been someone from Apple or possibly a external engineer whose job relies on not upsetting Apple. The certification courses have rules similar to the NDA's for developers that cover repair docs.

     

    Apple could be benevelent if they weren't so obsessed with secrecy & taking down sites that host old service manuals etc.

  • by hncl,

    hncl hncl Apr 1, 2014 11:36 AM in response to bold_seagull
    Level 1 (0 points)
    Apr 1, 2014 11:36 AM in response to bold_seagull

    My older than I can remember Cinema display just started to exhibit the no-image short-long-short light symptoms this afternoon.

     

    Without much hope in my heart, I searched on "repair apple cinema hd display," found this thread, and read until I found Mr. Jakobean's fix.

     

    Still skeptical, I figured it wouldn't take very long to do, and at least I could say I tried.

     

    My Cinema display is now working again!!!!! OK, it's less than an hour since it came back, but what a simple and wonderful little fix.

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