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Green / Red / colour pixels on external monitor

Today I bought an 24inch LG 24EN43 external monitor for my mid-2009 15inch MBPro. It is connected via mini displayport and HDMI cable.

I am seeing flashing coloured pixels /noise / artifacts ( mainly green but some red) on the left side of the monitor that gradually get less as they get further from the left edge. This happens in both mirror mode and extended desktop mode. It happens on all external monitor resolution except 720p. This resolution is fine for some reason.

My MB screen has no issues at all.

I have checked for loose connections. Tried restarting screen and mac. All drivers and software is up to date.

Any ideas would be greatly appreciated.

Thank you.

MacBook Pro (15-inch Mid 2009), OS X Mavericks (10.9)

Posted on Nov 23, 2013 1:21 PM

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6 replies

Community Specialist

Nov 25, 2013 8:35 AM in response to mjsteny

Hi, mjsteny.

Thank you for visiting Apple Support Communities.

The article below will walk you through some troubleshooting steps when experiencing issues with external displays.

Apple computers: Troubleshooting issues with video on internal or external displays

http://support.apple.com/kb/HT1573

Cheers,

Jason H.

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Level 1

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Dec 29, 2013 2:42 AM in response to jason269

I got the same problem, but nothing from this (http://support.apple.com/kb/HT1573) worked for me.

I use an 27inch Samsung S27C750 for my mid-2010 13inch MBP.

Any other ideas?

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Level 5

6,138 points

Dec 29, 2013 2:46 AM in response to epslon

Have you tried a different cable? Sounds like possible interference. Just a thought.

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Dec 29, 2013 3:57 AM in response to BobRz

i tried 3 different hdmi cables. also i tried to connect my PS3 with the cable and the monitor: there are no problems.

I also reset the NVRAM/PRAM and the SMC. -> nothing 😟

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Level 5

6,138 points

Dec 29, 2013 4:02 AM in response to epslon

It could be a hardware issue. A Genius Bar eval would be free, you might want to try that. Also, does anything in this thread help?

https://discussions.apple.com/thread/1946855?answerId=9197746022#9197746022

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Dec 29, 2013 4:56 AM in response to BobRz

nothing worked. i tried a custom resolution with switchResX but after restart it was the same problem..

tomorrow i'll visit the apple store..

thanks for your engagement 😉

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Green / Red / colour pixels on external monitor

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