12-06-2010, 11:11 AM

Hi guys-

Im in hopes of getting a real quick answer here, and I I apologize if this has already been stated. Heres what I have:

Model Name: iMac
Model Identifier: iMac7,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 2 GB
Bus Speed: 800 MHz
Boot ROM Version: IM71.007A.B03
SMC Version (system): 1.20f4
Graphics card: ATI Radeon HD2400

I just find it quite odd that after never having a problem with Leopard, that all of a sudden I upgrade to snow leopard (right over top of leopard) that I get all the lines going through my screen and black outs--where I have to reboot. Ive read many problems in other forums/sites like this and nobody has a solution--nobody.

Replies range from take into apple genius, re-install snow leopard, clean install, reset PRAM/SMC, disc utility repair, permissions repair, smc fancontrol, etc. Does anybody here have a solid response or better idea?

Heres what I think it is: I dont think my ATI graphics card can handle Snow Leopard at 1680 x 1050 resolution. Which is ridiculous if thats the case. So far, for 2 hours last night (10-12:30am) and part of today (7-11 am), there have been no problems with lines, screen black outs at 1344 x 840 resolution. The past 2 days after installing snow leopard I was getting frozen screens, screen black outs and graphic problems every hour or 2.

I beg for help on this as it has consumed me for 3 days now. I want to go back to Leopard so bad if I cant get this fixed.

Thanks so much!

Reese

12-06-2010, 02:06 PM

Heres what I think it is: I dont think my ATI graphics card can handle Snow Leopard at 1680 x 1050 resolution. Which is ridiculous if thats the case. So far, for 2 hours last night (10-12:30am) and part of today (7-11 am), there have been no problems with lines, screen black outs at 1344 x 840 resolution. The past 2 days after installing snow leopard I was getting frozen screens, screen black outs and graphic problems every hour or 2.

You're right about the ridiculous part. Your ATI card can handle the 1680 x 1050 resolution. The operating system has nothing to do with that. The depth of color and resolution should be the same for SL as it is for Leopard.

Run a test for us: The next time your screen displays the black lines or any abnormality, take a screen shot. Screen shot, not a photo...

If those same lines show up in the screen shot, we can narrow the problem down to the graphics card. If they don't show up, we then need to look to the display or its supporting components.

Post back and let us know.

12-06-2010, 02:37 PM

Will do thanks for the reply back.

Also, I just got off the phone with Apple and he had me run a disc utility (where there were some errors which were repaired) twice and we repaired permissions as well. We also put the original Leopard disc in and ran a hardware test where everything came back positive.

Funny thing is Ive been through the disc repair process 4 times since this all started happening 3 days ago, even installed Snow Leopard twice so I dont know if it will work. The only thing I didn't do is repair permissions "each" time I repaired the disc so maybe that might work. I'm back at 1680 x 1050 right now, its working fine so far--who knows.

Keep you updated. Thanks again.

Reese

12-06-2010, 06:35 PM

update: since my last post Ive had a frozen screen where mouse moves but nothing works on keyboard. Had to power down and back up again. Then 1 hour later I had a black screen episode.

beyond frustrating and at a loss for words.

Thanks

12-07-2010, 01:04 AM

It's beginning to sound like graphics processor troubles. If possible, get a screen shot so we can make a better determination of what's wrong.

Is your iMac still under warranty or Apple care? If it is, you probably need to think about taking it on in and let them trouble shoot it. If it turns out to be graphics related, that means a logic board swap. Let us know.

12-07-2010, 04:23 AM

Bottom line: it is almost certainly just coincidental that these graphics issues happened around the same time as the SL install, since they have nothing to do with each other.

12-07-2010, 08:54 PM

Well I did a clean sweep of snow leopard, re-install and it was fine for the day. Just right now the screen went frozen to a bunch of black vertical lines covering the whole screen. I cant do a screen shot because my wireless keyboard is powerless. Im going to have to assume is the graphics processor.

One of things that I am just stunned about is this device was made in 07. I took it out of the box in August 2009, and the graphics processor goes out already? I dont run any gaming on this thing or anything. Matter of fact I only have 40 gigs total of downloads on the drive. Is this normal?

I do not have apple care.

Man this stinks.

Thanks


Reese