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Green flickering pixels on my monitor

by ediblecastle / October 10, 2008 10:04 PM PDT

my monitor - HP LP2475w. running at 1900x1200 res
my computer - Dual 1.8Ghz Mac G5

I know this is a PC hardware forum. But bare with me please.

my problem - i have green (sometimes pink, once red) flickering pixels on some parts of my screen. They are not always in the same positions, in fact they move in accordance to the image currently on the screen.

here are a couple of photos I took to better illustrated the problem:
http://www.willarbuckle.com/knuj/pixelexample.png (pink vertical line, 1 pixel wide)
http://www.willarbuckle.com/knuj/greenpixels.jpg (when moving the window, the green pixels will move with it)

I've tried the monitor with a Windows laptop, as a 2nd screen. and there was purple pixels on the desktop wallpaper.

I had a cheaper LCD monitor about a week ago (returned it because it wasn't very good quality) but it worked fine with my setup. same resolution etc.

So I suppose all these experiments point at the monitor being faulty.

But when I change the screen resolution. the problem is non-existent on some resolutions and back again with others)

I've just swapped the standard DVI-D cable with a heavy duty DVI-I cable as both the computer and the monitor female ports accept DVI-I, so I thought it was best to give it a shot. But this gave horrendous results: see here: http://willarbuckle.com/knuj/redngreen.jpg plus the whole screen flashed on and off repeatedly.

I'll send the monitor back to HP but was wondering if anyone had any ideas to what causes this?

I suppose I'm just a bit reluctant because I've already had to send back another monitor and it's a hassle. Plus I've read on other forum posts where people have had several displays replaced... but had the same problem on each new display. There's actually a discussion over on the apple forums that's lasted about 2.5 years with no one solving the problem.

Any ideas? Thanks,
-Will

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" the problem is non-existent on some resolutions and back "
by R. Proffitt Forum moderator / October 11, 2008 12:04 AM PDT

" the problem is non-existent on some resolutions and back again with others)"

To me this nails it as the display is mis-rendering the VGA signal. Sadly to fix this you need to try other than VGA connections or change the display. Also, if you can control the refresh rate, drop it to 60Hz.

"I've tried the monitor with a Windows laptop, as a 2nd screen. and there was purple pixels on the desktop wallpaper."

You've proven to me this monitor has issues not in the actual LCD but in the circuitry that renders VGA to the LCD.
Bob

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did you mean DVI?
by ediblecastle / October 11, 2008 12:27 AM PDT

Thanks for the reply.

The display doesnt have any VGA connections. When u say VGA, did u mean DVI?

the computer only has 1 DVI port (and 1 port specially for apple displays)

I also only have the option to run it on 60Hz to begin with.

The monitor also has a HDMI port. but I don't have an HDMI-DVI cable to try it.

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Alphabet soup connections.
by R. Proffitt Forum moderator / October 11, 2008 12:51 AM PDT
In reply to: did you mean DVI?

You got the message. Try other connections. I will not attempt to untangle or define all the possible ABCD connections. Sorry.
Bob

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hdmi-dvi
by ediblecastle / October 11, 2008 1:01 AM PDT

cool. well i'll try to get my hands on a HDMI-DVI cable on monday and see if that sorts it out. cheers.
-Will

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Thanks for understanding.
by R. Proffitt Forum moderator / October 11, 2008 1:12 AM PDT
In reply to: hdmi-dvi

I had to hit google up for more info as I connected up HDTV for the first time this year.

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returning...
by ediblecastle / October 14, 2008 7:24 PM PDT

I tried a high quality shielded DVI-DVI cable and a HDMI-DVI cable. but unfortunately the problem got really bad and worse respectively.

after getting no help from HP email tech support or phone I will be returning the monitor. and hopefully getting a new one which works. tempted to blow more money on the monitor just so don't have to deal with HP again. (took me about 45 mins to talk to a real person who actually tried to help)

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was the problem ever solved?
by splitfinger32 / June 8, 2009 1:20 AM PDT
In reply to: returning...

I have a similar problem with my screen. It's an older LCD tv/monitor. I recently bought a new plasma and wanted to use the old one as my monitor, but I have the same problem with random pixels flashing green/red/purple, etc.

I thought it might be a problem with my graphics card (it's 4 1/2 years old, nvidia 6800 gt). I've tried using both vga and dvi connections, but both have the same result. However, when hooking up the tv to my newer laptop, there are no discolored pixels.

Any ideas?

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