27" iMac with graphics "artifacts"

[omega7441]

hi everyone

I'm a long time lurker and occasional helper to the forums when I can, and I'm usually very good at diagnosing and fixing issues but this iMac has be a little stumped as to what to suggest to my client.

the customer has a 27" iMac Mid 2010 running 10.9.2

photographer who uses a ton of adobe products, photoshop, illustrator, etc.

they complain that dots will show up from time to time and then everything locks up.

online hardware diagnostic with doing option + D tells me this model isn't supported. i pulled the hard drive and tested with MHDD which returned almost like new but with two warnings (not errors)

i blew out considerable dust from the fans and heat sinks, ran a prime program and geeks 3d GPU test.

THE ONLY TIME I SAW THE ISSUE MYSELF WAS AFTER REASSEMBLING IT I SAW THE GREEN AND BLOCK DOTS FOR ROUGHLY 20 SECONDS BEFORE THEY DISAPPEARED.

I have run 3d GPU on testmark x64 (opengl 4.0) which it does with 10 fps and gets everything really hot. have run this in 30 to 40 minute sprints and then run prime. slamming it with all that alternating for 2 hours and nothing acted up.

i have found similar issues but apple told other people to wipe it due to a kernal issue. this didn't fix their issues. others have reported and showed screengrabs where they had the same issues, nuked os, replaced graphics and they issue persisted.

replacing graphics card is roughly $350+ and one heck of a gamble.

does apple have a supported hardware test that will test graphics? i have a 19" iMac with mavericks as well and mine won't test online or with mavericks usb "Boot"

thanks to anyone who reads all this and responds, I can't think of anything else to do other than nuke it or throw parts at it

 

[Markverhyden]

1. Have you tried to boot this from a clean install to see what happens?

2. Have you booted into recovery mode and run Repair Disk and Repair Disk Permissions?

3. I'm assuming you have applied all OS as well as app updates.

4. To be quite honest my bet is it's a motherboard issue since the machine freezes when the spots come up. I've seen the same thing on Wintel machines.

Also if you do not already have these:

Link to a KB on how to get the Apple tests done

http://support.apple.com/kb/ht1509

Link to the service manual

http://tim.id.au/laptops/apple/imac/imac_27_mid10.pdf

 

[omega7441]

1. Have you tried to boot this from a clean install to see what happens?
No but this is was going to be my next option

2. Have you booted into recovery mode and run Repair Disk and Repair Disk Permissions?
yes i have done both

3. I'm assuming you have applied all OS as well as app updates.
that is correct

4. To be quite honest my bet is it's a motherboard issue since the machine freezes when the spots come up. I've seen the same thing on Wintel machines.
Thank you for this and the bellow information. I will follow up with any results.

Also if you do not already have these:

Link to a KB on how to get the Apple tests done

http://support.apple.com/kb/ht1509

Link to the service manual

http://tim.id.au/laptops/apple/imac/imac_27_mid10.pdf[/QUOTE]

 

[altrenda]

You could use something like TechTool to check the video ram, or GPU test http://www.geeks3d.com/20121129/gpu...nchmark-furmark-gimark-stress-test-videocard/ . to see if it's the videocard.

 

[Moltuae]

I'm no Mac expert, but my guess would also be the motherboard; more specifically the GPU solder joints.

I've had a few Windows laptops with this kind of problem (most commonly HP). I didn't know iMacs suffered from the same problem until I had one for repair a while ago -- turns out it's quite a common issue with some iMac models. Assuming that's the problem here, re-balling the GPU or replacing the motherboard is the only fix.

 

[14049752]

For those saying that it's the motherboard; This model has a separate video card. Replacing the video card, not the motherboard, would be the fix.

 

[omega7441]

I'm no Mac expert, but my guess would also be the motherboard; more specifically the GPU solder joints.

I've had a few Windows laptops with this kind of problem (most commonly HP). I didn't know iMacs suffered from the same problem until I had one for repair a while ago -- turns out it's quite a common issue with some iMac models. Assuming that's the problem here, re-balling the GPU or replacing the motherboard is the only fix.

I have actually fixed around 15 HP laptops with a reflow (taking a heatgun and heating the surrounding area) so I am very familiar with this.

For those saying that it's the motherboard; This model has a separate video card. Replacing the video card, not the motherboard, would be the fix.

While you are correct about the add on graphics card, the LCD \ LED panel doesn't plug directly into the card if my memory serves. It actually plugs into a part of the motherboard directly above where the graphics card connects to the mainboard

see this link for image from ifixit

You could use something like TechTool to check the video ram, or GPU test http://www.geeks3d.com/20121129/gpu...nchmark-furmark-gimark-stress-test-videocard/ . to see if it's the videocard.

thanks for the tip, but the GPU test \ stress test I have been doing is the GPU test that you have linked. running it for 30 minutes to an hour doesn't yield any problems.

I'm going to be talking to the customer today about maybe fresh installing it so see if that is an option. Thanks for the ideas and will report back if I have any break throughs.

 

[anonymous Mac Tech]

I'm no Mac expert, but my guess would also be the motherboard; more specifically the GPU solder joints.

I've had a few Windows laptops with this kind of problem (most commonly HP). I didn't know iMacs suffered from the same problem until I had one for repair a while ago -- turns out it's quite a common issue with some iMac models. Assuming that's the problem here, re-balling the GPU or replacing the motherboard is the only fix.

For those saying that it's the motherboard; This model has a separate video card. Replacing the video card, not the motherboard, would be the fix.

Just like 14049752 stated. It's a separate video card. First thing to try is zapping PRAM. Also, test the memory thoroughly. Obviously boot to external to rule out software. Run multiple instances of chess/grapher get the machine good and hot or even better yet stream some 1080 HD content to the machine to make it freak out. It shouldn't take long. But, after seeing many of these cases I'd bet it's the video card going south.

 

[Digital Sage]

It's a common issue. Some reflow the gpu on the graphics card and it's fine. My bet would be it's definitely the graphics cards. Bad solder joins.

 

[DanF]

Had the same issue on my personal MacBook Pro... was so frustrated when it happened :/ Was the NVIDIA chip.

 

[cyabro]

I just did my first graphics card replacement in a 27" iMac. Pretty straight forward. It was an ati model.

 

[omega7441]

Just an update. I followed up with customer about a week later and they have had no issues with it, previously they could only work on it a few hours before it froze up.

The only thing I that I really "did" was remove quite a bit of dust from the heat-sink and fan assembly's. More time will tell, but so far they are pleased and that's all that matters.

 

[Dee]

Artefacts are always not a good sign, in most cases in my experience this indicates the GPU onboard RAMS that may have hair line fracture on some solder joints, if GPU had been the case then you would get all kinds of symptoms from crashes to blank screen. If indeed it comes back with lots of random stuff onscreen, highly suggest a reflow of all the onboard GPU rams as my first step and see if that fixes the problem, indeed the chipsets on these macs overheat and so if not sufficient venting, things always at some point will go bad. Hope this helps.