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I have an apple 30" monitor plugged into my late 2008 15" Macbook Pro. Every once in a while when I start up the Macbook pro the monitor will first turn on, then off and repeat indefinitely until I unplug the DVI connection. If I place a finger on the power touch switch on the side the monitor, the display will usually stay on as long as I hold my finger there.

Has anyone else had this problem. Anyone know what causes it or if it can be easily fixed.

The monitor is not under any kind of warranty at this point.

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Just mentioned this to a colleague and he wondered if you'd noticed the power light doing anything when you switch the monitor on from cold? Apparently the Cinema Displays will briefly flash the power light as a diagnostic if there is an internal problem, and this might be something you hadn't noticed. I expect there is a doc on the Apple website about the meaning of the different flashes (etc). –  robsoft Dec 17 '10 at 14:15
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3 Answers 3

up vote 3 down vote accepted

Stan Marsh Unpluging Internet

I don't know why, but if you unplug the monitor power (not just press the power off switch) and then plug it back in the problem goes away.

My guess is that the on/off switch on the side of the monitor is heat sensitive and calibrated for the temperature of the room, if the room temperature changes, things become un-calibrated, and the monitor starts thinking it's receiving a touch even when it's not. The stan marsh method resets this calibration.

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+1 for South Park –  Martín Marconcini Dec 10 '10 at 13:02
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I have a similar problem with my 2009 15" Unibody MBP, intermittently.

It seemed to be to do with the mini-DVI to DVI connector. My laptop goes everywhere with me and is invariably plugged into other things whenever I arrive anywhere, so over time the ports start to get a bit 'soft'. I found that if the mini-DVI to DVI connector wasn't completely sat in the dvi-out socket properly, then the display it was plugged into would flicker.

I have 2 'identical' Apple mini-DVI to DVI connectors, and one of them seems much more prone to being a 'loose fit' than the other one.

Can you borrow another mini-DVI to DVI connector to try it?

Your heat theory is an interesting one but I doubt that the calibration is that sensitive (I've got an older Cinema Display model with the touch-sensitive brightness and power controls, and I've never known it turn itself off/on regardless of the temperature of my office, which varies wildly throughout the year). I could be wrong, though! :-)

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The Late 2008 Model mac book pro was before they switched to the uni-body design and does not have a mini-DVI port, just a regular DVI port. Also, my monitor doesn't flicker, it turns on and off, when it's on the signal quality is perfect, then it turns off, then on , then off again –  Ben Dec 10 '10 at 23:55
    
Oh, sorry - I didn't realise there was that difference between the models. All I can suggest now is that it's a problem with the cable or, as you say, some kind of problem with the switch itself. How strange. :-( –  robsoft Dec 14 '10 at 10:56
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I also found that @Ben's answer worked for me, but it help kept happening more and more often. Eventually I called Apple because the monitor was still under warranty and Apple replaced the monitor--just the monitor, not the power supply so it seems that @Ben's right on what the problem is.

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