27 in iMac grey / white screen of death

iMac 27 inch Mid 2010, 2.93 GHz Intel Core i7. Yosemite 10.10.5.
Recently my screen started flickering and then turned white/grey. I was able to fix it using disk utility to repair permissions. Was good for a week and suddenly turned all white again. Tried safe reboot, zap PRAM... nothing.
Do you all think it’s my Graphics / Video Card? ATI Radeon HD 5750 1024 MB?
A new one is $350. Do I need to replace with the same exact one and is it difficult to do?
How do I know if it's the Graphics / Video card... or the Hard Drive? I called Apple and they said there is no extended/hidden warranty on this. Wondering if I should just purchase a new iMac.

Thanks!

tastyorange said:

How do I know if it's the Graphics / Video card... or the Hard Drive?

Click to expand...

Hey there tasteyorange...nice to see a longtime member such as yourself checking in!

As far as the issue. I think what you want to know is if you have a hardware or software/OS issue. Here are some things to try:

- If you can...connect an external display to your iMac...and see if the external display has any issues. If not...then the issue could be with the iMac's display panel or iMac's display cable. If the external display also has issues...then we have to test further.

- To test if the iMac has a hardware or software/OS issue...you could boot the iMac from an external hard drive with an OS installed on it. If no more issues...then could be an software/OS issue on the iMac's internal HD. If there still are issues...then we are probably talking something hardware related...and very likely the video card.

But...even if the video card is the issue...maybe if we're lucky it only needs to be cleaned & the thermal paste replaced.

Worst case scenario...the video card has gone bad...and needs a replacement. And as you mentioned...even on a 7 year-old iMac...a replacement video card is pricey.

But give the more simple tests a try first...before we talk seriously about a new computer.

HTH,

- Nick

Thanks for the info. I don't have another display available... or a hard drive with OSX on it.
Would repairing permissions fixing it for several days be a clue as to what it is?

tastyorange said:

Would repairing permissions fixing it for several days be a clue as to what it is?

Click to expand...

My gut feeling is no (but I guess I could be wrong). When you fixed permissions recently...maybe it was just a coincidence that the display worked again.

It would REALLY be great if you had an external display and an external HD with OS X on it to do some troubleshooting. If you want to do DIY fixes...it really helps to have this sort of stuff around.. Otherwise you can end up spending some big bucks paying a professional to do things you can do at home.

A few other things you can try:

- Download, install, and run the app called Onyx. It's a free maintenance app. If you think the problem was fixed by repairing permissions (problem is something software based)...this is probably one of the best free tools out there (and probably better than most or all apps you pay for). Stick to the Onyx default settings.
- If you're feeling adventuresome...you could open up the iMac...remove the video card...clean it up real good...and replace the thermal paste. I did this on a 2009 iMac I used to own. It would always shut down when I played videos...and this fixed things. No guarantees it will fix things in your case (maybe I got lucky). But doesn't hurt to try...and long as you don't damage anything doing this.
- If you feel it's a software issue...you could also try a fresh install of the OS (make sure to do a backup first).

HTH,

- Nick

I know it's been awhile, but I brought the imac to a place that fixes them cheap. It was the graphics card. They fixed it for only $230. maybe they used a used card, I don't know... but it works now and they were able to save most of the stuff on my hard drive.

That's good to know. Hopefully it will last a bit longer.

Thanks... at least a year I hope!

I know it's been awhile, but I brought the imac to a place that fixes them cheap. It was the graphics card.

Click to expand...

Glad to hear you have such a place available to you, such places are nice to have available and aren't always supported properly by the Mac world.




- Patrick
======