Q: Small lines / dots over parts of screen

Sounds like I'm experiencing the same problem - 3 1/2 year old iMac G5 ILS with a yellowish grid pattern covering the entire screen. Looking at it too long makes me feel like I'm getting a bad migraine. The problem suddenly started last week when I was burning a DVD but cleared up for several days after I powered down over night. Now it's back and the comments in this thread do not make me very optimistic!

Here's a screenshot of what the problem looks like on my iMac.

My three years with AppleCare on this machine ended last August but I'm going to take it into my local Apple Store to see what they say. I'll make them aware of this thread too.

well, I took mine to the Apple store to the genius bar. Mine is just over 3 years old, and I was told it was the logic board. The price for the board is just under $1000, and the labor is $136. I parted my iMac out, you can see all the parts on ebay now. I am so disappointed, but it is not worth sinking over $1100 to fix it. At the genius bar, they plugged in an external monitor, and it had the same hash marks. That let me know it was not the monitor, but the video ... which is part of the logic board. I hope your problem is not the same.

Just an update: I took my iMac G5 to the Apple Store this morning. They confirmed the failure and traced it to the logic board as it also exhibited on an external monitor. The best part is they said there would be no charge for repair since it was a known issue that would have been covered under AppleCare which I had originally purchased. Whew!

This confirms to me to always buy the AppleCare. I've usually gotten back at least some of the extended warranty price in avoided repair costs. And this repair would have cost much more than AppleCare.

Phil, I also had two motherboards ewplaced within a few months after purchasing My iMac G5 (isisght). Fortuantely I had AppleCare and other than at that time the tech from a nearby town didn't know how to get the back off it was finally done.

More recently I had the OS quit recognizing the boot or anything else except the <install disk 1> but then it wouldn't boot the HD or install so .. I took it to local Tech Advanced (Authorized repair and reseller) and they got it working again (see post under "displays). Three days lost and $100+ but .... ???

This is a grievous disappointment to me. I switched to simplify after 22 years of DOS and Windows.

Here is one more with a pink line on the screen. Suddenly appeared a few days ago. It has disappeared a couple of times, but comes back. It is a vertical line on the right of the screen. Like most of you, mine is about 3 and a half years old. Mine is a PowerPC.
Shirley

I had a local reseller take a look at it, he says the logic board has to be replaced. He'd charge €831 ($1074) for a new one (incl. working hours).

I also started getting the dots over the icons and the lines around the cursor at the end of February. I ran the hardware test and I have been told that the error message I got means it is a problem with the video controller chip and the only way to solve it is to replace the logic board. My iMac is just under three years old and I don't have Applecare. I had checked it's serial number against the recall but it was just outside the range too.

Since yesterday I have been experiencing the exact same problem as iMPH. Since I was running Tiger and thought it might be a software problem I installed Leopard, but the problem remains. A friend of mine said it has to do with the way transparency is being handled by the system, as the grids of dotted lines only appear around icons, windows, the menubar, and the dock.

My iMac is 3 years 9 months old, and was working fine until now, never had any problem before. My applecare contract ended last june. If indeed this is a logic board problem, it will be my second Mac that dies this way as my 5 year old iBook G3 broke down last year with a dead screen due to a faulty logic board.

Did you get a chance to take your iMac in to the Apple Store to get it look at?
I am having the exact same problem with my 17", if possible could you let us
know what they said? Thanks.

Given the date this problem started for everybody, I can't help but wonder if the latest software update (for 10.4.11 users) is somehow causing the issue. I know for me, the day I installed the latest software update (about two weeks ago), a most troublesome issue immediately popped up: Finder kept quitting about every 15 seconds. The issue was resolved by turning off a particular preference on Stuffit.

Now today, I started up my iMac G5 (purchased August 2005), and I'm having display issues. For me, there are random blurry spots on the display. Oddly, if I move my mouse over certain areas, the entire display shifts about a sixteenth of an inch and it seems to sort of expand in height and width at the same time. Also, when I mouse over an area of the display that is still crisp, it turns blurry and vice versa. I've already tried rebooting and resetting display preferences to no avail. Next I'm going to try resetting the P-RAM and SMU. I doubt that will fix it.

I had this same "display blurry in spots" problem with my 17" Powerbook g4 (purchased at the same time as the iMac) at the beginning of January after experiencing a kernel panic. But, the laptop had had serious display issues for quite some time (the multiple cyan, magenta, yellow vertical lines filling up the right side of the screen, with more showing up on a daily basis). A few days later, the display went black and I had to send it in for repair. The backlight cable, inverter board, and the LCD screen were replaced. All problems are now resolved.

I've read that these kinds of issues are related to either the video card or the logic board. I can't help but wonder if the latest software update had some bug in it that slowly kills your iMac, one component at a time.

I can't believe such a sinister plan would be part of a corporation's way of doing things, but it just seems quite odd to me that so many of us are currently having problems with the same machine at this exact time.

Obviously, most people who have the money would just go buy a new machine.

It *****. Unfortunately, I don't think a PC is going to behave any better than a Mac. It seems like it's just becoming the standard of practice for manufacturers to sell crap product and fail to stand behind their faulty products. It doesn't make them reduce the price any though!

Update: About three weeks after my AppleCare expired, I took my iMac to the Genius Bar. Short story is they replaced the LCD screen at NO CHARGE, but didn't tell me why there was no charge. I really didn't press for an answer; didn't want them to change their mind!

Long story...last week we took a MacBook Pro for service, and while waiting for what turned out to be an easy fix at the Genius Bar, got into a discussion with the Genius about my recent free iMac repair. He said the LCD screen was replaced at no charge, even though AppleCare had expired, because the problem was a known issue.

Bottom line: if possible take it to a Genius Bar at an Apple store. The worst that can happen is they won't fix it, and you are out time and gas (and, of course, a screen). But I wouldn't be surprised if you got a free repair!

hey guys, isn't anyone surprised how this came to happen starting January, and how in the last 3 days, many more are reporting the same problem. I got it today. We are desperate, we need this computer for a research project. Hopefully someone at Apple will roll his sleeves and start looking into it. We need a quick solution.

Please keep interacting,

One more thing, keep trying. I inserted a fresh OS X system disk, as if to re-install it, and before formating I had second thoughts. Removed the disk, re-started and Da Da!!!! it was working all right!!!

It has to be firmware, it has to be, it is the same generation of G5s. Lets press for a solution from Apple.

I've got it too! My dock items looked just like the sample image by iMPH. I've tried several of the solutions suggested by other posters. Apple needs to acknowledge that there is an issue and kindly make users aware of their options. I may just need to junk my well used iMac24 but I'd like to know for sure that this is my best option. Way too many people are reporting this issue for it to be ignored.

I had the same issue as iMPH.

Disabling Quartz Extreme, fixed it all except for the dots around the mouse cursor.

To do this enter the following command in Terminal:
defaults write /Library/Preferences/com.apple.windowserver GLCompositor -dict tileHeight -int 0 tileWidth -int 0

To re-enable Quartz Extreme, enter the following command in Terminal:
defaults delete /Library/Preferences/com.apple.windowserver GLCompositor
(I found this here http://felipecruz.com/g5-freeze-ups-problem.php)

Let me know if it works for you, and if you find a fix for the cursor.

Thanks

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