Wavy colored lines on screen - little like a photoshop selection effect

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Level 1

8 points

Wavy colored lines on screen - little like a photoshop selection effect

Hi All,

This morning when I woke my 20" intem iMac from it's sleep, I was presented with a screen full of wavy "ie moving" curved lines moving around the screen. It looked a bit like a selection in an image editing program like photoshop. In all other respects the machine was working fine. Anyways, after mild panic and a few reboots, no dice, still wavy lines.

I did notice that the initial mac icon as it booted looked normal, then the wavy lines kicked in, so I had a little hope that it wasn't a hardware problem.

Long story short, resetting the PRAM (command option+PR) during reboot fixed it for me. Phew.

Just thought I'd post in case someone else runs into this problem.

Cheers

iMac 20" - 2Ghz core duo - 2Gb Ram, Mac OS X (10.4.6)

Posted on May 18, 2006 5:40 PM

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Answer 1

myhighway

Level 5

7,270 points

May 20, 2006 10:44 PM in response to colourpixels

Dale,
Just curious. Are you up to date on both the system firmware (update last month) and the SMC firmware (update past week)?

If so, and if you have since performed a SMC reset as well, without any improvement, I'd recommend calling AppleCare and getting them to take care of the problem for you. There's no reason for you to put up with this once you're past the obvious quick self-fixes. Letting it go too long without any action could make it seem that you don't rank very highly the importance of a fix. You've heard the old saying - give 'em an inch and they'll take a yard?

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Answer 2

myhighway

Level 5

7,270 points

Jun 4, 2006 3:39 AM in response to colourpixels

Dale,
Thanks. I've never noticed, but can't say that I'd be paying too much attention at that particular moment. I'll have to see if I can replicate that on one of mine.

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Answer 3

colourpixels Author

Level 1

8 points

May 19, 2006 8:46 PM in response to colourpixels

Ok, so I thought it was fixed, but awaking my iMac from sleep this afternoon and the wavy lines are back. Resetting the PRAM on reboot doesn't work this time so I'm back into panic stations.

Anyone have any thoughts on what to try?

Thanks
Dale

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Answer 4

colourpixels Author

Level 1

8 points

May 19, 2006 9:17 PM in response to colourpixels

Well, continuing on with my soliloquy, rebooting for about the 20th time holding down
ctrl + option + command + a + v

And my mac came back looking as I would hope, wavy lines gone. Whether it had anything to do with that key combination (that I found in a thread somwhere) I have no idea. If it happens again I'll call applecare support, guess I have it for a reason eh.

Ok, hope no-one else is running in to this frustrating problem. (but if you have post here so I at least know it's not just a dud machine)

Cheers
Dale

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Answer 5

colourpixels Author

Level 1

8 points

May 20, 2006 10:15 PM in response to colourpixels

Well, this time it happend fom a cold start (ie from fully powered off for a day) A single restart using the conrol option+command+av and it was fixed.

I think I'm going to just leave the darn thing on permanently at this point...

cheers
Dale

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Answer 6

colourpixels Author

Level 1

8 points

May 20, 2006 11:49 PM in response to myhighway

Yes, I did download that sms firmware update (and unplugged my power etc as described), it Didn't seem to have any noticable effect.

When you return a machine via Applecare, do you essentially lose everything on your machine that you've installed etc, or do they mirror the drive accross for you?

I'd hate to have to go through the whole installation process again and getting everything just right again (you know...quicksilver settings etc etc) which is why I've held off calling them.

Thanks for your response, much appreciated.

Cheers
Dale

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Answer 7

myhighway

Level 5

7,270 points

May 21, 2006 12:55 AM in response to colourpixels

Ah, yes, the usual reason not to give up a computer for repair. They might simply replace your display, leaving you with the rest of the unit and original hard drive in place. There may be no problem occur, but it's always wisest to be prepared for a repair failure and back up prior to giving up the machine. While the repair personnel might be interested (or not) in protecting your interests, I'd keep in mind that they're only human and do make errors.

I don't know what will happen next if you choose to do nothing. What if the problems escalate for you and you end up losing everything on the hard drive - are you backed up and prepared for that possibility? Not fair, I know, throwing the doomsday scenario at you, but .... your decision.

Edit-
You might want to check the warranty language, as I imagine that Apple won't agree to be responsible for your data, even if they try to help you out in that respect during service.

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Answer 8

colourpixels Author

Level 1

8 points

May 21, 2006 6:11 PM in response to myhighway

Well the control av etc appears to be a no go. What I think is happening is that while the machine is cold it's doing these wavy lines...then when some critical temp is reached the display comes good on the next reboot (which was just coincendence that I was trying out the a=v combo)

Sigh, applecare call tonight.

Cheers
Dale

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Answer 9

emanuele

Level 1

0 points

May 30, 2006 1:37 PM in response to colourpixels

Hey, I've got the same problem. I just post a message (monitor-sleeping mode than display totally confused),

what are your suggestions? I phoned Apple Support, I made the PRAM, but now what are you doing? What could we do?

emanuele

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Answer 10

colourpixels Author

Level 1

8 points

Jun 1, 2006 2:59 PM in response to emanuele

Well after a call to applecare I took it into the repair centre for a fix-up. Got it back today (after almost a week sans computer...oh the horror) and the problem seems fixed. Apparently they changed the display.

So if you experience this problem, the moral of the story is call applecare straight away, there's no software solution to it.

Cheers
Dale

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Answer 11

colourpixels Author

Level 1

8 points

Jun 2, 2006 7:39 PM in response to colourpixels

Well the new screen certainly doesn't have the old problem:
http://www.colourpixels.net/downloads/WavyLines.jpg

but it does have the other "refresh rate/ interlacing problem described in other threads.

Cheers

Dale

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Answer 12

myhighway

Level 5

7,270 points

Jun 4, 2006 3:00 AM in response to colourpixels

"refresh rate/ interlacing problem described in other threads.

I've seen a couple mentions of this, but haven't seen anything very accurately described so that it's understandable to someone without the (supposed) issue. Without knowing more, I'd suspect lack of maintenance, a common cause of many different issues.

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Answer 13

colourpixels Author

Level 1

8 points

Jun 4, 2006 3:08 AM in response to myhighway

Lack of maintennance wouldn't fit my situation, as my iMac is all of a couple weeks old, and this new screen is < 1 week old.

Lets see if I can describe it.
1) when iMac comes back from "display off" from energy settings
2)There is a slight flicker to the screen, most obvious on the white of the tool bar for me. It looks similar to a monitor at too low a refressh rate, or the slight shimmer you see when playing an interlaced video on a non interlaced display. (ie the video split into fields)
3) I'd photograph it if I could, but it's fairly subtle and would be hard to capture.

cheers

Dale

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