repair 23" Cinema Display (no power, after power surge)

Discussion in 'Mac Accessories' started by gucio, Apr 18, 2008.

  1. gucio macrumors newbie

    Apr 18, 2008
    Hi there,

    I had a bad power surge (USB hub that was plugged into the back of the display had the wrong power cord plugged in... very stupid mistake I know!!) take out my 23" Cinema Display. The display shows no sign of life (no power light, etc) and the brick has been tested and is OK. My local service place says that they will have to send the display back to Apple which means a minimum of $400 for repair so I'm wondering if anyone has had a similar issue that they resolved successfully? The service place suggested that Apple would replace the logic board but is there any way to test to see if this is the main issue? I have seen logic boards sold separately online but would be hesitant to buy it without know that this would fix this issue.

    Any suggestions or advice would be great!!!

  2. mperkins37 macrumors 6502a


    Jan 17, 2007
    Phoenix, AZ
  3. jjahshik32 macrumors 603

    Sep 4, 2006
  4. taylorwilsdon macrumors 68000


    Nov 16, 2006
    New York City
    Does not cover damage from power surges.
  5. mperkins37 macrumors 6502a


    Jan 17, 2007
    Phoenix, AZ
    If you're handy I see transformers & Boards on ebay all the time, Crack it open & replace em yourself, If you take it to Apple it'll run ya.
  6. gucio thread starter macrumors newbie

    Apr 18, 2008
    I'd love to try and fix it... any thoughts on how to figure out what is broken inside (ie, logic board, transformer, inverter board... etc)? I don't have any fear about opening up the back... nothing to lose at this point :) Thanks for the help!
  7. mperkins37 macrumors 6502a


    Jan 17, 2007
    Phoenix, AZ
    Power surges generally take the power transformer out first. I would get that first.
  8. dprorok macrumors newbie

    Apr 14, 2008
    Several people have suggested replacing the transformer, but the transformer is in the brick, which the OP has stated has been tested and is okay. DC power comes out of that brick and runs into the monitor. I haven't taken an Apple display apart, but there aren't likely to be a lot of power components inside the display itself. There might be a high voltage DC converter in there, but I doubt there is a transformer in there.

    The OP says there was a power surge, but then talks about a USB HUB with the wrong AC adapter. Was this USB hub then, in turn, plugged in via USB to the Apple display and it was a surge over USB cables, not power cables, that occurred? If this is the case, you likely toasted whatever board is immediately connected to the USB ports and the melted/smoked/popped capacitors, resistors, or chips near and connected to that USB port should be a pretty clear indicator of what part needs to be replaced.
  9. brtittle macrumors newbie

    May 15, 2008
    Cinema Display - Troubleshooting

    Not sure about the 23", I have a 22".

    The external power supply is 16Vdc@3.8Amps.

    You can measure the voltage on the two larger pins on the 3-pin round connector. You can get a cheap meter from radio shack.

    If you want, I can send you a manual on how to take a 20" apart that is probably simular.

    My 22" only has one surface mounted fuse inside.
    You can measure the fuse by turning off power and setting the meter on ohms. A good fuse measures 0 ohms.

    There is a +5V regulator on the main board. It should measure +5V. Once you have the back off of it, If you send me good pictures I may be able to help further.

    Forgot to tell you. The backlights for the LCD display may be very high voltage (+800Vdc) be very carefull. I found a data sheet for the display by google the Sharp Number that was on the display. It had a pinout for the display in it. You can try this also. The USB operates off of +5V. The main CPU on mine was a 42 pin Dip motorala processor. Send me the P/N on your CPU and I will tell you where to measure P/S voltage on it. The Monitor has several voltage reglators, invertors ect that all run off of the 16VDC external power supply (Brick).

    Hope this helps

  10. rdw283 macrumors newbie

    Sep 13, 2010
    I just had this same issue, plugged in a USB cord to the hub attached to the monitor. The monitor tripped my UPS and now won't come back on. We have 40 of these monitors at our company and this is a first for us.
  11. easthampton macrumors newbie

    Oct 9, 2010
    Cinema Display Power Issues

    Hi- Sorry to be posting this so late to your problem. It sounds like you might have a problem similar to mine. My 24" HD Cinema Display stopped working. The 75 W brick checked out OK, and the Apple Dealer wanted to send the display back to Apple for diagnosis. I found a thread online that suggested trying the display with a 150 W brick.

    It worked!

    It seems that for some unknown reason, some 24" HD Cinema Displays stop working with the 75 W adapter and need more power. You can diagnose the display's problem by the pattern of the blinking light on the front of the display:

    Here’s what the flashing power light means:


    If you see three short flashes, the display is receiving the wrong video format or is set to an unsupported resolution. Make sure your display is compatible with the computer you’ve connected it to, and restart the computer. If the problem continues, try resetting the parameter random-access memory (PRAM) by shutting down the computer, then turning on the computer and pressing and holding the Command-Option-P-R keys. Hold the keys down until the computer restarts and you hear the startup sound for the second time.

    If you see a “short, long, short” flash pattern, make sure you’re using the correct power adapter for the display.

    If you see a “short, short, long” flash pattern, the display is detecting a backlight error. Check your display’s power connection and restart your computer. If the problem continues, contact Apple or an Apple Authorized Service Provider.

    Hope this helps you!
  12. camero90, Apr 25, 2012
    Last edited: Apr 25, 2012

    camero90 macrumors newbie

    Apr 25, 2012
    covington, Ga.
    here is a fix for the 23" cinema hd display when the power brick not working !
    it requires you to take apart the monitor, it's very easy, google it, when you get
    the panel out lay it flat on a soft towel, connect the power brick and dont worry
    about video, at the center top of the logic board pull back the black tape, there will be a 3 wire black connector red,black, and a very small gray wire, check the red and black wires with a volt meter, if the voltage the pulsing high and low the brick is at foult, you will need a +24v power supply for the next test, cut the red,black, gray cable about 2 to 3" back (if this test is neg. it may require you
    resplice the connector back in). however, this worked for me very well, as i got a 24v power supply out of a floor standing copier whole unit for 15.00 and got alot of other goodies to. put the power supply in a cabnet run seperate power wire, this works great and i through that power brick as far as i could get it. i connected the the power supply and plugged it in and started the computer and vola we got display. cut off the gray wire and do'nt worry about connecting it.
  13. Maxq108 macrumors newbie

    Jun 5, 2012
    Hey Camero90
    I got the same problem and I'm glade I've found this post.
    Something is not clear for me in your explanation if you could please
    Help me out, I'm not really an expert in electronic fixing, would you mind to take few shots of the final job I'm kind of confused about the 24v power supply, About what type and how you have wired everything together, and where to store it,I would really appreciate that.
    Thanks in advance

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