Problem with nvidia geforce 8800 GS in early 2008 iMac

You can ask,however I have no idea what they charge for diagnostics but it's worth a phone call. Use the link I provided earlier to help you find an AASP in your area. You can contact them to explain symptoms and they may be able to give you some ideas over the phone.

I have to be honest though I think it will be expensive to get this thing fixed. If you find that is the case you may be able to make money from it by parting it out and selling the parts on Ebay. If you're lucky you may earn enough to buy a Apple refurbished iMac.

I am having the SAME EXACT Issue took my iMac to Genius at the local store has been there 3 days and they don't know what is wrong with it. This particular iMac has had 2 major hardware failure for me already and this is the third and I still don't know what it is.

I had a hard disk failure

I had a video card failure

Replace with NVDIA Geforce 8800 GS

Now 1 year 6 month this They are in the process of changing the video card

1 major HARDWARE PROBLEM PER YEAR.

My last 2 macs, 6 years EACH and no problems at all. I think mac quality has slipped.

If you find the problem let me know so I can let the Apple store know.

If your machine is covered by AppleCare then you should be politely askng for a replacement machine.

It is not under Apple Care. I had to pay for the last video card $564, this video card will be the same, they said it could the Display which would be $400 + Labor or Logic Boad $600 + labor. When you spend $2300 on a computer you should expect top quality, I am very disappointed with this Mac. Seems like more people have issue with this model. The Little Pod one was so wonderful 6 years and was still kicking when I changed and not one issue. And my 6600 tower 6 years no issues.

But this one

1 year 2 month in Hard Disk

2 years 3 months Video Card

3 years 6 months Video card, logic Board or Display?

Sounds like poor quality parts.

Sounds like you should have gotten AppleCare but passed it up when you had the opportunity. Granted it should have lasted longer under normal conditions however Apple cannot control the conditions users put their computers in. We haven't seen what or where the computer has been living but I recall a couple of weeks ago someone posting about their computer overheating and blaming Apple. When I pulled the string a little more he admitted he was a gamer and it was over 100 degrees F in the room the computer was in due to a heat wave. This is well above normal operating conditions. I've seen other complain about similar things where they had their computer in hutch so it had no ventilation and then wondered if that might affect it. Other users will live areas where the power is dodgy (blackouts, lightning storms, brownouts etc..) and then do nothing to protect the computer and complain.

Anyhow maybe you should ***** where you have the computer's operating conditions. Is it getting clean power (could you maybe put it on a UPS), does it have adequate ventilation, is it working in an area that is within Apple's operating conditions. If so then pehaps you just had a run of bad luck... it happens.

The location of my computer is on the same desk my other 2 computers were and in a open temperature controlled area, open desk and circulation.

You are right about the Apple Care but $2300 for a computer and we should then have to add another $252 because they are creating inferior products is not my way of thinking.

I had such success with the last 2, I thought it wasn't worth the money trusting Apple would keep their quality up.

While you are protecting Apple and presenting conter points, I am a 16 year user and this is my first 3 and 1/2 year bad experience. First 12 were fantastic. That also includes other apple products, 4 ipods, 1 nano, 2 iphones, 1 airport, and 2 laptops.

In fact both laptops never had an issue. Had first one 5 years, second one is on 2 years. This iMac may be a lemon.

I agree you may have gotten a lemon, my 4 year old iMac has been the most dependable computer I've ever owned and I'm guessing that represents the majority of machines.

I'm not sure where you live but $252 for AppleCare seems expensive, here in the US it's $169 for an iMac and can easily be found for as low as $120 by resellers such as Amazon and other authorized Apple Resellers.

At any rate your experience with that paticular machine hasn't been good and you have a right to be frustrated. I guess all I wanted to communicate is I don't think that is representative of that model otherwise you can be sure the press would have been making banner headlines of it.

I believe that I have a problem with my Nvidia GeForce 8800GS (in my iMac 2008 24").

When using my Mac one day, the screen suddenly went completely black. I took the machine to an Apple store and we tried an external monitor - but no video.

my iMac is outside AppleCare warranty (by about 9 months - having expired in Jun11) and in ringing Apple they said that mine is not one of the machines affected by the now widely-known Nvidia graphics card problems - see the threads on the www.nvdidadefect.com forums. Nvidia know of a problem with some of the video cards they produced.

On startup, I get (internal) LEDs 1, 2 and 3 illuminated, and the Mac boot chime sounds. The hard drive tries to access data. But the iMac fails to boot.

I purchased a Radeon 2600 Pro for an iMac 24" and I installed that. Of course, it was a perfect fit. If it is the Nvidia graphics card that is failing, then replacing it with another Nvidia card doesn't seem the sensible thing to do.

But no luck - I only get LEDs 1 and 2 illuminating (LED 3 flashes only briefly when power is first applied) and I no longer hear the Mac boot chime. That combination of status LEDs would seem to indicate a problem with the graphics card.

I was hoping (based on success stories on the www.nvidiadefect.com forum) that I might have been successful too in changing out the Nvidia GeForce 8800GS for the ATi Radeon 2600Pro.

Any ideas - especially from those who have successfully installed a Radeon 2600 in place of the Nvidia 8800GS in the early 2008 iMac 24"? If success is related to firmware on the main system board, then my options are limited.

Having nothing to lose, I put my Nvidia video card in our kitchen oven for 20 minutes at 200 degrees celcius, then let everything cool down. This technique is known as reflowing.

I put the iMac back together and hit the power switch.

I heard the familiar iMac boot chime, then saw the normal white screen and grey Apple logo, a normal bootstrap, and then my login prompts as normal - as if nothing had happened!

Reflowing the video card worked, but of course I don't know how long the fix will last. I was amazed at how effective this repair seemed to be! I effected this "repair" on 15Jun12, and today (18Jul12) the iMac is still working perfectly.

I discussed the issue with an Apple Genius at the opening of Apple's Broadway (Sydney) store a couple of weeks ago, and he suggested that I copy my posts from the www.nvidiadefect.com forum here on the Apple Support Forum. This is a slightly modified version of the two posts I put on the www.nvidiadefect.com forum. I'm not sure whether Apple Australia would be prepared to do anything to help out should the card fail again.

Gary

I brought my iMac to Genius Bar yesterday. They were very courteous and helpful. However, they ended up wanting to replace the NVIDIA card even though I told them that this problem will keep on coming back because of the heating problem of that specific card based on what I have read in numerous forums. They are pointing to the possibility of having a logic board issue, too -- I told them that this is usually a misdiagnosis whenever there is a faulty graphics card for iMac early 2008 series. They agreed and they are hoping that it is simply a graphics card issue at this point. I do hope that simple replacement of the NVIDIA card fixes the issue. However, another option would be to give up if this doesn't get fixed and Apple might not want to replace it with a new machine (although I guess replacement of the entire machine might also be one of their options since we know that this is really a problem with NVIDIA in iMac early 2008 series). I am an iMac, iPhone, iPad, iPod, Time Capsule user and now I am thinking whether I should switch back to PCs instead of Macs if they don't take care of me this time....

Got my iMac today after getting a call from Apple Store last night. They replaced the graphics card as they have said. So far it is working. It is a bit slow so maybe I need to check the hard drive...

So far the iMac is still working. Thanks to the Genius Bar guys. I will update everyone else here if I still see any problems.

The reflow failed on 22Sep12.

I still see a white startup screen with grey Apple logo and spinning spoke progress indicator.

UNTIL OS X attempts to load the WindowManager - at which time the system reports "a problem" as part of a light grey multi-language message and then attempts to restart.

The iMac crashed a couple of times before becoming totally unbootable and so a couple of crash reports were generated on the subsequent reboots and posted automatically to Apple. Unfortunately, I can't access them with the machine in the state it is in.

The cause of the crash was reported as a Kernel Panic as the WindowManager process called an NVIDIA I/O routine.

To me, that's a clear sign that the NVIDIA 8800 GS is failing again.

Rather than try to re-flow a second time, I have an appointment with the local Apple Genius Bar this Thursday. I'm armed with a range of material from the web - reports, news stories, etc. Let's see what happens on Thursday.

Gary

Until now, the iMac is still working. For Mountain Lion, I use smcFanControl. At Windows 7, I turn on CPUID Hardware Monitor, then I execute MacFanx64 (macfanx64.exe 1200 2000 2000 since I have three fans).