2009 27" iMac - Distorted image

dynamix12

macrumors newbie
Original poster
Jun 18, 2017
5
4
Good day all, I'm looking for some help with an iMac (11,1) that froze up and then rebooted and now when booting I get a status bare and just before the login screen the screen becomes distorted. I have an extended display that the distortion appears there as well. I tried reinstalling the OS, Sierra with no help. Also tried the AHT with a quick test and the longer test. There were no faults on either test. Images below are some of the issues. Any help would be greatly appreciated. Thanks.
 

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dynamix12

macrumors newbie
Original poster
Jun 18, 2017
5
4
Appreciate your response, just a quick followup. On intial power up the screen is normal and the status bar goes about half way and screen flashes and then displays the lines in the photo. That would still be faulting the graphice card? Thanks.
 

GlennieM

macrumors newbie
Jun 19, 2017
8
5
Wodonga, Victoria, Australia
Appreciate your response, just a quick followup. On intial power up the screen is normal and the status bar goes about half way and screen flashes and then displays the lines in the photo. That would still be faulting the graphice card? Thanks.
I have the same iMac 2009 as you have with the identical problem. Started failing 6 months ago and found the only way I could get it to get to complete the start up sequence was to start in Safe Mode. (Press and hold shift until progress bar starts to go across). The problem is indeed the graphics card as was diagnosed by my local Apple guru who I have complete faith in as to his knowledge and honesty. Starting in safe mode disables sound, USB devices but not my Time Machine external backup drive), DVD Writer and a heap of other things such as add-on Virus program don't work either. Makes the iMac a PITA to use but at least you have some warning of the impending and final doom that awaits. The replacement graphics card is available but I have been told the issue was down to the manufacturing process where the solder flow coating of the back of the board was an issue and resulted in dry joints appearing over time. Unfortunately the replacement boards were all manufactured during the same period so if you do replace it then it might fail at some indeterminate time after that. Some people have been able to extend the life of the board by baking it in an oven. What temperature and for what time period I don't know but it is hit and miss apparently and you might get only a month or so extra time out of it. You would have to Google it to find the details.

Anyway, I have been holding off and replacing it and limping along, hoping for the latest iMac update and a month ago it died in the arse (ass if you are American). I ordered a new i7 on the 6th and just waiting for it to arrive. I am sorry that the old one died but hey! Consolation, I get to own a new shiny and fast toy.
 

b06tmm

macrumors regular
Jul 23, 2009
236
23
South Louisiana
The graphics card in my mid-2011 iMac died a few weeks ago and since my AppleCare expired I figured I had nothing to lose by baking the card in my oven. I baked it at 200C (390F) for 11 minutes and replaced the thermal pads with K5 Pro thermal paste. While I had the logic board out I also cleaned all of the fans and vents.

I did this on the 7th and it is still running strong today. I did install SMCFanControl so I could monitor the temps and boost the fans when the temps get a little high.

If I wouldn't have mangled the graphics cable on reassembly the cost for the repair would have been around $15 for the suction cup and thermal paste. The new cable was $21.45 via Amazon.
 

fruitpunch.ben

macrumors 6502a
Sep 16, 2008
586
133
Surrey, BC
Graphics card has been getting flaky on my 2009 iMac as well.
Screen flickers a lot on start-up and I get wavy lines on the screen although they go away after booting, and the screen is not uniform (particularly in the summer when it gets warmer [no AC here] there are display issues).

Fingers crossed it gives me another year or so!

I have the same iMac 2009 as you have with the identical problem. Started failing 6 months ago and found the only way I could get it to get to complete the start up sequence was to start in Safe Mode.
Glad to know it it gets worse I might have an option to get a few more months out of it
 

Cheruman

macrumors member
Apr 30, 2007
48
71
Exact same thing happened to mine late last year, wasn't really cost-effective to repair unfortunately but I guess 7 years isn't too bad.

I took out the SSD I fitted a while ago and am just waiting until Apple update the Mini (lol) before I buy another Mac, can't afford their high-end stuff these days :(
 

dynamix12

macrumors newbie
Original poster
Jun 18, 2017
5
4
Just wanted to drop and update. Finally busted into this iMac and pulled the video card which was a fairly easy process, and went ahead a baked it for 10min at 390F. Let it cool down put it back together and powered up. The moment of truth was the power up chime and booted like there was never even a problem. That was 9-Jul and still working like a champ. Thanks for all the advice.
 

b06tmm

macrumors regular
Jul 23, 2009
236
23
South Louisiana
That's fantastic, thanks for the update!

From what I've read on various forums, baking the card is a temporary fix and it may crap out again after a few months. I have refrained from playing games and doing graphic intensive things on mine, just using it for email and web browsing and so far it's been flawless.

Good Luck!
 
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danielwsmithee

macrumors 65816
Mar 12, 2005
1,117
397
Appreciate your response, just a quick followup. On intial power up the screen is normal and the status bar goes about half way and screen flashes and then displays the lines in the photo. That would still be faulting the graphice card? Thanks.
Yes mine did the same thing when it failed.
 

dynamix12

macrumors newbie
Original poster
Jun 18, 2017
5
4
That's fantastic, thanks for the update!

From what I've read on various forums, baking the card is a temporary fix and it may crap out again after a few months. I have refrained from playing games and doing graphic intensive things on mine, just using it for email and web browsing and so far it's been flawless.

Good Luck!
I understand that it's only temporary fix, but if it gets me a couple more months than that's great. I'm just not ready for another investment. A few dollar investment in thermal paste is better that a couple hundred.