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

189986 Views 344 Replies Latest reply: Apr 1, 2014 11:36 AM by hncl RSS
  • Scott Perez-Fox Calculating status...

    Just used the so-called Jakobean Method to repair my 23" Cinema HD Display. Like so many others on this thread, the last time I used this monitor successfully was just before the power went out in my apartment (thank you, Hurricane Sandy.) I also moved during this time and feared that it was phsyically damaged in the move.

     

    SO relieved that this little hack has worked. In my case, I used a thin strip of blue painter's tape and a piece of thin plastic to get the job done. Not sure if these are the best materials long-term, but at least now I know this method exists, and that it works for my conditions.

     

    If anyone is interested, here is the YouTube video I used to get inspired.

     

    https://www.youtube.com/watch?v=4dMPtczFwDs

     

    Thanks

  • robin2468 Level 1 Level 1 (0 points)

    HI Folks,

         I had the short, long, short error on my 23" Cinema display last November (2011) and used the jakobean fix.

         As of today (Dec 11th, 2012), still working.

         Thank you all.

  • Adam Barisoff1 Calculating status...

    23" Cinema recently died with short-long-short. Replaced 90watt adapter for same at Apple store, no dice. Found this thread - and yes it worked, thanks. Anyone been using this a long time have some feedback? Still working? Did monitor eventually fail and after how long?

  • louis1946 Level 1 Level 1 (0 points)

    I've been running for a year on the fix of blocking that one pin in the connector. No problems. I used a narrow strip of black electrical tape to cover the pin.

  • hexdiy Level 1 Level 1 (60 points)

    Hey Scott, great for you, but how long is our memory on the subject? Update/ bump: http://pixelchimp.net/blog/pixel-chimp/apple-23-cinema-display-possible-fix-shor t-long-short-error

    Actually he is the authority here, I was just the messenger reviewing the thread for you all. & Thank you all BTW!

  • Drew Reece (Re:co) Level 2 Level 2 (310 points)

    LOL thanks hexdiy, I'm pretty sure you helped out too

     

    I did get an interesting contact on my site, it led to this second post about actually replacing the power supply with one for powering LED's.

    http://pixelchimp.net/blog/pixel-chimp/replacement-power-supply-apple-cinema-dis play

     

    Eroni's suggestion is that as the cold cathode florescent lamps start to age they draw more current. His theory is supported by what I have found by searching & reading. CCFL's run from high voltages that are stepped up from the 24V input.

     

    Logic suggests that the 'pin hack' is not a great idea, for 2 reasons (that I can see).

    1. You are simply fooling the monitor into thinking it is OK to overload the power supply (it thinks it is using a 150W supply, but the standard 23" supply is built to provide 90W).
    2. The 'paper/ plastic' insulation can move as it is inserted, blocking other pins causes all the current to pass through fewer contacts (Apple made so many pins for a reason, to carry the current).

     

    I vaguely remember someone mentioning earlier in this thread 'brown marks' or discoloring around the power connector after using the pin hack, I'm not convinced it is a sensible long term solution. Check the pins for scorch marks if you dare disconnect the pin hack.

     

    I'm glad the hack is still working for people on here, but please consider there are probably better solutions such as checking the components or getting a power supply that can cope with what could be a greater load. In theory the supply will have thermal cutout/ fire prevention circuits & should be able to run for periods above the max rating, but who wants to trust their workplace or home to that?

  • rebusBakery Level 1 Level 1 (0 points)

    An alternative to the cover the middle pin trick is to simply cut the cord. Well, the lead that connects to that center pin anyway.

     

    Went through the process so many had followed. Monitor died for no good reason, LED indicates power supply is dead. Replace power supply but no fix. Find this or related thread and try cover that tiny pin. Tried that a few times and lost patience so here is what fixed it:

     

    Carefully remove about an inch of the outside plastic of the power cable. Then carefully slice and seperate the shielding web to reveal three wires and some filler. Two of these are power carriers (red and black and heavier gauge) and one is the feedback lead (thin and grey.) Cut the feedback lead, tuck everything back into the cable, plug it in.

     

    Worked great, no fuss over trying to get the center lead blocked, no scorching or risk of shorts or such. So what if the monitor is tricked into overloading the power unit that was originally just fine for it. Beats having a dead monitor!

     

    Have one of my better monitors working again. Many thanks to the original discoverer of this fix.

  • Drew Reece (Re:co) Level 2 Level 2 (310 points)

    rebusBakery wrote:

     

    Worked great, no fuss over trying to get the center lead blocked, no scorching or risk of shorts or such. So what if the monitor is tricked into overloading the power unit that was originally just fine for it. Beats having a dead monitor!

     

     

    Tell that to your insurer or the fire brigade after a fire, they may disagree.

     

    It may just be that overloading simply shortens the life of the Apple supply by making it run a fraction hotter than normal, personally I think a computer monitor is not worth risking my life over (if this was used in my home). Especially when you can get an appropriately rated replacement supply cheaply and wire it up yourself in a matter of hours.

     

    I also contemplated just cutting the sense wire inside the monitor but decided it was better to try to troubleshoot the fault instead. I'm not trying to rain on your parade, well done for getting it working again, just take care with it. You have effectively defeated one safety feature with this hack, the question is how many other safety measures did Apple fit? Thermal cutouts, over voltage protection, additional fuses… ?

  • louis1946 Level 1 Level 1 (0 points)

    I haven't noticed the power supply overheating, but I can't argue with you, Drew, it's certainly better to replace the power supply.

     

    You say one can get an appropriately rated replacement supply cheaply. Could you point me in the right direction? I can do basic soldering, but not anything complex. Thus if I had to find a technician to make the replacement power supply work, it could add up to a cost that would exceed the value of the monitor.

     

    Thanks - LJ

  • Drew Reece (Re:co) Level 2 Level 2 (310 points)

    I can't take the credit for the cheap power supply, but the info is on my site…

    http://pixelchimp.net/blog/pixel-chimp/replacement-power-supply-apple-cinema-dis play

     

    Basically Eroni brought a LED power supply that is rated for 120W at around 24V. It should provide enough extra current to cope with extra load created by 'failing' CCFL's. It's adjustable & cheap compared to the Apple version.

  • Jast_DK Calculating status...

    Thanks jakobeon


    MacPro with old 23" HD ACD and newer (2008) 20" Apple CD. After unplucking 1 week the screen on the 20" Apple CD would not turn on. However, onn/off function and MacPro detecting was ok.

     

    Tryed the jakobeon solution with 1,5 mm paperstripe. It did not work, paper got teared when connecting.

     

    Tryed again succesfully with Post-It paper sticky side out. That worked .

     

    Will now monitor potential overheating.

     

     

  • Drew Reece (Re:co) Level 2 Level 2 (310 points)

    Jast_DK wrote:

     

    Tryed again succesfully with Post-It paper sticky side out. That worked .

     

    Will now monitor potential overheating.

     

    I feel like I have explained this many times in this thread.

    Covering that center pin makes the monitor think it is a higher rated power supply (like the one for the old 30" displays), so it decides it can draw more current, possibly more than the supply was designed to provide.

    It's the power supply you should worry about overloading/ overheating, especially since you have inserted paper into the contacts.

     

    It's a safety feature that people are circumventing - like not wearing a seatbelt or lifejacket in the hope that an accident doesn't occur.

     

    Good luck with it.

  • Jast_DK Level 1 Level 1 (0 points)

    @ Drew Reece (Re:co)

     

    Thanks Drew. Sorry, I did not explain myself.

    It is the PowerSupply I will be monitoring.

    It is the standard 65W that was provided for my 20" Apple CD.

     

    Now, after a few hours I can not notice any change and since it is the same powersupply and screen I do not expect to experience overheating.

     

    It is very strange through that this "Apple Cinema Display 23" - Blank Screen, "short-long-short" LED code" error appears - out of the blue, and no Apple explanation for the LED code error, to be found anywhere!

  • Drew Reece (Re:co) Level 2 Level 2 (310 points)

    It's a service engineers code. Find the right manual & it has a table of the LED patterns, they are out there if you look, I think my blog mentions them too

     

    I believe the cold cathode fluorescent lamps backlights (ccfls) can start to draw a higher current as they age or begin to fail. Since the voltage is stepped up from the 24V input a small change in the high voltage can cause a larger load on the input. The circuitry for the ccfl's seems to detect if it can draw extra current based on the power supply, which is 'sensed' via that center pin.

     

    It may be completely safe, but I worry about doing things that are outside the makers intent.

  • Jast_DK Level 1 Level 1 (0 points)

    @ Drew

     

    Drew Reece (Re:co) wrote:

     

    It's a service engineers code. Find the right manual & it has a table of the LED patterns, they are out there if you look, I think my blog mentions them too

     

    I believe the cold cathode fluorescent lamps backlights (ccfls) can start to draw a higher current as they age or begin to fail. Since the voltage is stepped up from the 24V input a small change in the high voltage can cause a larger load on the input. The circuitry for the ccfl's seems to detect if it can draw extra current based on the power supply, which is 'sensed' via that center pin.

     

    It may be completely safe, but I worry about doing things that are outside the makers intent.

     

    Thanks.

     

    The apple manual download side does not work for the ACD!

    http://manuals.info.apple.com/en_US/CinemaDisplays_20_23_30inchUserGuide.pdf

     

    What is your blog link?

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