iMac 24" (early 2008) with Nvidia 8800GS - Repair hopeless ?

So later that night I was able to get an image back after not using it for about 4 hours. I'm worried though that it's in the process of failing though. Going to keep my fans running high while using it. I am going to the apple store anyway because when they last swapped out my graphics card they messed up my optical drive. First they thought my problem was the hard drive, then the optical, then finally the graphics card.

John Stark wrote:

So later that night I was able to get an image back after not using it for about 4 hours. I'm worried though that it's in the process of failing though. Going to keep my fans running high while using it. I am going to the apple store anyway because when they last swapped out my graphics card they messed up my optical drive. First they thought my problem was the hard drive, then the optical, then finally the graphics card.

Sounds good. When my first card started going bad I'd get odd screen images, frozen pixels (particularly on my second monitor) and such. Then it failed completely. I took some screenshots as well as some pictures with my iPhone when it began acting up to show the Genius at the Apple store.

Initially they thought it was my hard drive as well. That's understandable, especially considering that my iMac was over four years old at the time plus hard drives fail more than any other hardware. In the end it was the graphics card of course.

Hope it hangs in there and let us know how things go!

I'll write in this Sunday afternoon. Going to apple 14th street in manhattan Sunday morning. Been experiencing more problems with the black screen but no image distortion during operation.

John

What happened, John? Did you get any concrete help for your computer issue?

ok I'll TRY to make this short... but it's been a very long process.

First visit, mentioned above. They called back saying it was the HD failing... I asked if they we're sure because I didn't want to pay for another HD, and asked them if they could please run test with a new HD to confirm there would be a fix. They did so, but they also used my current HD with a totally clean install, and ran tests. After 18 tries, no black screen. So I broght it back and began manually rebuiling by mac from selected items from my TM backup. Everything was going fine then.... Black screen. About 4 days in.

I brought it in again. This time they looked at everything... and even hooked up a new Graphics card... the problem continued. But they did replace the optical cable (feeds power to the optical drive and some componets to the logic board) and the HD. I just coughed up for it this time and after stress tests... they found it to work again. I brought it home again. About 3 days in.... Black screen.

Back to the apple store... At this point I was getting a "?" at boot, sometimes, and sometimes blackscreen. After 5 days with them they call back and say they tested everything... all hardware and parts... and found the problem in the logic board. I had at this point paid $542 in repair costs since last July, but they offered to discount that amount toward another iMac. I took it.

This early 2008 model runs hot, and dust gets into the frame. The new imacs can't be opened, except for memory, and no dust gets in there. Plus it runs ALOT cooler. I had this machine for 4 years. Not long, but at this point I need to move on and the Store was good to discount the repair costs.

All in all I'm happy... a bit poorer but happy with a new iMac.

John

After some effort, including reflowing my graphics card twice, I managed to escalate my Nvidia 8800GS video problem to AppleCare in Singapore. I supplied them with information on what I had done, as well asarticles I had downloaded from various online sources relating to Nvidia failures. I was quite open about having opened my iMac and removing the video card, as the iMac was outside the extended AppleCare period I purchased with the machine.

My escalation to Singapore occurred after I had been told to contact the Apple Store at Bondi Junction (where I had been having the iMac looked at) and them offering to take the machine. But the Bondi Junction store rang before my appointment to cancel, saying that having read my material and seen that I had opened my iMac, it wasn't covered. Of course, this shouldn't have been news to them, as I was quite open with them about having opened my iMac and reflowed the video card.

Singapore then intervened and offered to have me take my iMac to a local reseller. The offer was that they would replace the video card if I would pay for labour costs. My machine was fixed within a couple of days, and my iMac sits happily in the garage as the machine in my workshop - tv, audio, Arduino development, web surfing, etc.

It has been running faultlessly.

So, my recommendation is that you persevere.

BTW: I did "upgrade" to a 27-inch iMac during the process, when all seemed lost, and my 24-inch iMac didn't accept the ATi 2600 card I bought from e-bay.

Apologies for my ignorance but why Singapore how did you go about contacting AppleCare in Singapore? Thanks.

From Sydney, my call was escalated to AppleCare in Singapore.

Having the call escalated to the next level is the important step - you may still have to show that you've gone through the Genius Bar, etc before the call is escalated. I spoke with two different people in Singapore - the second person I spoke with took ownership of the problem and ensure that it was resolved. The first person I spoke with in Singapore also was helpful but tried to have the Apple Store resolve the issue - and they cancelled the appointment that they made on my behalf when they realised that I had opened the Mac - something that I openly admitted from the outset. The Store woudn't budge on the matter of me having opened the Mac.

As it was, Singapore arranged for a local Apple reseller to effect the repairs.

By the way, my iMac and it's new card are working perfectly - I occasionally send an e-mail to the contact in Singapore to confirm that all is still well, and to again say a quick "thanks".

There is plenty of material on the web about NVIDIA and the failure of the ball grid array with their GeForce 8000 cards - I'd suggest gathering as much of that material together before heading off to Apple.

Good luck. It look a little perseverence, but it was a worthwhile outcome for me.

Thank you for all the details and advice.

I have endless material found online so I will make sure I make contact with all that at hand.

Thanks again.

Badzim: Let us know how it goes. I've only had to replace the Nvidia 8800GS in my Early 2008 iMac once...a little over a year ago...and it's still working okay. I've stopped using my second (Apple Cinema) Display with it for the most part and avoid stressing it by playing games, etc.

I still do a bit of video editing and when I do the GPU still heats up quickly. I use iStat Menus to monitor the temp. I bump the fans up whenever it goes above 65C or so.

If it goes south again I'd like to know how things go for you.

TIA!

Hi guys, I originally posted on this discussion under ShaneMiller1121.

I decided to take it upon myself to repair this issue.

I took the thing appart, the GPU is on a separate MXM card so can be take out of the logic board easily.

I completely re-balled the GPU using lead solder, taking it off with a heat gun, cleaning the contacts on the board and the underside of the GPU, applied the new lead solder with a 40GBP solder iron and a steady hand, Cleaned up all the old thermal paste from both the GPU and CPU with some cleaning alcohol, cleaned all the boards, vents and the chasis.

There is a fan right by the GPU on the right hand side of the chasis, I took this out and drilled a series of holes through the back of the case, and fitted a 25x25 PC fan the the back (outside) of the case where the new holes were and soldered the power cable for the fan to the power cable of the internal fan the draw power to it.

For the fan on the bottam left hand side (for the heatsinks) I drilled another series of holes in the alluminium front bezel where the fan is as a more substantial exhaust for the heat.

I have been stress testing this for a while and it hasn't gone above 25 Degrees C, and I am running Mavericks with rock-solid performance.

When the problem existed, just running logic pro 9 on its own with OSX lion would push it to the limit but everything is smooth now with the fix above running Mavericks and Logic pro X.

This fix is not for the feint of heart, but for some one who is technicaly skilled, this is a 25GBP fix.

The new thermal paste I used was high grade Antec Formula 7 Nano diamon Thermal compound which I got from Maplin for 15GBP.

Hope this helps 🙂

ShaneMiller1121 wrote:

Hi guys, I originally posted on this discussion under ShaneMiller1121.

I decided to take it upon myself to repair this issue.

<snip>

Thanks for the detailed post...and wow! Not for the faint of heart is right...I'd have real heartburn drilling holes into either side of the aluminum housing much less both sides! But good on 'ya for going all the way!

I would have liked to have known how it faired after only re-soldering the GPU, etc....without the additional fan, holes, etc. but I suspect the eventual outcome would have been the same. I've read stories about folks that have reflowed the GPU and taken other drastic steps to get it working again. Ultimately it's obvious that it comes down to overheating though so your iMac should never have that problem again.

Since I last posted I bought a Late 2013 27" iMac. Although it only has one large fan (almost silent) even under high stress plus running another monitor the GPU never gets above 50c or so and remains around 32c most of the time. The NVIDIA 8800GS in my '08 iMac would climb over 80c under the same high demand so things have certainly changed.

My wife had an an '07 Mac mini so she "inherited" the '08 iMac and really likes it. I put a new SSD in it and that's really helped to keep it much cooler (and it's much, much faster). Since she mostly uses it for email, web surfing and Angry Birds I think it will last quite a while longer now. Fingers crossed becuase other than the GPU issues even after almost five years it's still an awesome machine.

Cheers again for the post, let us know how it goes and enjoy!

I thought about just re-balling and seeing how things went, but seeing as I already had the thing in pieces I thought I may as well do everything now to save me time later.

I have been toying with the idea of getting a newer MXM graphics card from an Asus (or Acer, can't remember which) laptop and changing the EEPROM chip and flashing a moddified ROM for Apples EFI but still need to do some more research into that before I go spending the cash.

Upgrading the processor is also a possibility as it is a Socket P processor and not soldered directly onto the logic board so I was thinking of upgrading from the Core 2 Duo 3.06Ghz to a Core 2 Quad (1066 bus speed) OSX should detect this as a quad core Xeon processor.

RAM is already maxed out at 4GB.

Apple don't want you to know these things, but there really are more options for these iMacs than first meets the eye 😉

Those would be some interesting upgrades for sure. Although I used to build PCs from scratch and enjoyed seeing what I could get out of a machine, these days I get to the point where the cost/benefit just isn't there and often just opt for something newer or in my case after five years, new.

FWIW your '08 iMac can be upgraded to 6GBs of RAM. It isn't widely known (or "condoned" by Apple) but it works fine. I've been running 6GB RAM for several years without any issues. Upgrading to an SSD was the very best investment though.

Best of luck and let us know if you decide to do some more work!

My NVIDIA 8800 is gone too... is function normal with little high Temp, but if heavy videoload Display is freezing.

Imac is now 5 years old. I here from a lot of people with the same machine and the same problem. It must be a design or a chip error...I don't understand that apple is ignore everything in case and offer no solution. 5 year old Imac for the garbage 😟