Overheating causing graphic issues

I had multiple problems with the iMac (late 2006 Intel Core 2 Duo 24")after a few years of use. The computer was running extremely slow even after all manner of fixes including bigger HD, resets of everything, Drive Genius fixes, etc. Then it started freezing in mid opening of applications with a distorted image of a half opened application plus lines through the screen. It became unusable with no fixes from Apple Store recommended other than possible logic board.

I opened it up again and thoroughly cleaned with compressed duster - fan blades, ducts, conductor and cooling fins. In addition the GPU was blown out as well as possible. Finally the gap in the duct between the CPU cooling fan outlet and the copper heat conductor was sealed with aluminum tape and a bit of tape was used around the openings in GPU to keep air flowing through it. (Note the iMac 24 MA 456LL/A that I have is quite easy to open. You do not have to use the credit car to pry back the levers found on some of the other iMacs.)

The unit was reassembled and smcFanControl was downloaded and installed. Before installation the GPU was running over 105˚F with no heavy use. After smcFancontrol even with heavy use the GPU rarely went over 98˚. The problems have disappeared and all seems well. The cost of repairs was $4.50 for a roll of tape of which I used about 6".

Hi. Finally I found the solution.

During last year my imac24" worked so hot. It was so noisy.

Now it's over.

Here is what I've done: one more fix

So will replacing the logic board/graphics card permanently fix this issue? Did they redesign the LB? Or if I have the GB replace, will I run into the same issues as before?

thanks

Phil

There are issues with the gpu in that model. It will overheat and burn off or cause other parts to decay fast like capacitors. The caps go as soon as you start seeing noise in the screen (ghosting, static in picture, hissing sound from the system that changes with picture movements like a window or mouse cursor) A replacement card is the only option if you do not know how to repair smd devices (surface mount devices on the board) The caps are the silver aluminum things. My guess is a design flaw in the heat sink or thermal compound.

There are confirmed reports that the heatpipe part of the heatsink is failing. Small pinholes have appeared in the heatpipe. This ruins the heat transfer capability of the heatsink and makes the GPU overheat. By simply replacing the heatsink the problem is fixed.

I also used smcFanControl and it fixed my same problem with the heat-caused graphics problems. I also placed smcFanControl on my Mac Mini that's in a little shed that the sun beats on in the summer, It fixed my lockup problem on the Mini

You might want to do a little cleaning, just recently, my ATI Radeon X1900 XTX in my pc was overheating, and acting up. I dissasembled the heatsink for the card, and cleaned the dust out of it (and there was quite alot of it, since i've had it for 2 years) and after that, removed the heatsink entireley to re-apply the thermal paste(i used artcic silver 5, the best stuff around) and not the card runs like new, the graphics card heatsink should be removable, and if your warrenty is expired, apple can't really help, so if you want to take apart your iMac, try cleaning out the dust, from all of the heatsinks (even the cpu) and then remove them and re-apply a thin layer of artic silver 5 (a tube costs about $10 at radioshack) and then put it back together.

Good Luck,

Chris

You do know that when you delete that file desktop composition is disabled. (quartz) It is probably the cause anyway though.

I've been having the same problems with my Imac 2006 with the NVIDIA GeForce 7300 GT card. I installed SMC Fan Control and it helped, I cleaned the fans 6 months ago.

Anyway I took the computer apart again and cleaned it throughly. When I took apart the fan on the left side, unsnapping the duct cover, there was a large amount of dust on the radiator fins of the graphics cooling heat sink. I estimate it was plugged about to 50%. I vacuumed it out and cleaned the fans, it seems to run cooler now as more air flow gets across the heat sink....

There was also a bit of dust on the air intake on the bottom of the computer.

It's worth a try.

Ed

Hello everyone.

Same story --- my 2.16GHz 2006 white iMac started to show all kinds of ill behavior (graphics noise and strips, completely garbled graphics, and system-hangs) all related to heating.

Following the tip I found here -- I installed smcFanControl, and it improved things for a while. However, it deteriorates over time, and now I can't use the machine unless the air conditioning is turned on in the room.

It starts to show signs of malfunction as soon as smcFanControl reports anything over 31celsius (round 90F).

Our area is very dusty, and I'm quite sure some cleaning can improve things again. However, I'm quite sure it can't SOLVE things.

In addition --- the internal superDrive stopped being able to eject discs, which again is something reported here. Up until now, I couldn't find reasonably priced internal replacement drive -- but now I saw some ~$90 used drives here.

I guess it is time to open the machine... My questions are:

1. Are there any detailed tutorials for replacing the GPU card?

2. Did anyone actually replaced his GPU, and (the iMac) lives to tell the story?

3. Where and How can one purchase the right GPU card for this rather old machine?

4. Are there any specific recommendations here for replacing the internal HardDrive (upgrade for bigger storage) to something which also RUNS COOLER ?

I never took apart this iMac, and the tutorials for replacing the optical drive don't exactly encourage me to try. Prying open the case seems a little dangerous - I could break some of the levers, or something).

I dealt with lot's of electronics in the past, but I remember macs to be a delight to dismantle (orignal Macs, Mac II series, Quadras, PowerMacs, PowerBooks G3 G4 and G5 Towers, Intel Mac Pro's and many others --- however, this seems to be very different, and very risky ---

I need some encouraging here :)

Thanks!

I also have the above problem with my 24" Intel Mac but am having a lot of trouble downlading smc fan controller onto my mac? It is either a windows based software that runs on an Intel mac under windows or a mac product that refuses to install. Once it requested last volume when trying to unzip? should I be using 2.2.2 or 2.4 version with Snow lepord?

I had purchased a 27 inch I mac circa 2009 or 2010 the first time that they were released. I think it was a core i7 with 4 cores and a 4670 or 4600 series gpu. The v ram was 1 gig and 1 tera hard drive. Don't recall the cpu. It may have been 2.8 or 3.2. I know that I was very happy with it the night before. What started my trouble is the next morning. I think I burned a dvd. 4.7 gigs. The screen started flickering. Went to black than back to white and black dots dancing. This went on for 5 minutes and the screen came back. I was good for hours. Just that first couple of minutes when waking up in the morning the computer that is after putting to sleep the night before and burning a dvd in the morning. This freeque me out. I return it. I exchange it 3 times with various other quality issues before I gave up and opted for a laptop. The laptop had all sorts of issues including external video flickering on a monitor. Two years of constant visits to apple store. One year in I had an exchange for a newer model. The newer model had logic board changed and fail similarly. About 6 months out of warranty I had a total hard drive failure. Apple refused to fix. I buy a hard drive at Micro Center for 79. The original 750 the new 1 tb drive. Apple refuse to even loosen the screws on the old hard drive. Special tool was needed. They did it for me at micro center for free. The only thing apple would do is help me reinstall the OS from their archive. The computer I sold on Craigs list for 1/3 the price I pay for or close to that. I by the mac book for 2800 sold for 1100 on crags list. So a bit over the 1/3 mark. Sad story is mine. Mind you while the hard drive is failing in a 12 month period the apple genius bar tech kept having me reinstall the software blaming on software problem for corrupt areas. This should have been the change of hard drive while it was under warranty. Shame on apple. I also filed with the City of Chicago consumer agency that told me there was nothing they could do for me. So apple is above the law. What can some one like me do with no real cash to fight the big dogs. I just have to except that big corporations with team of lawyers can get away with anything. All I can do is blog about this.

The articles I read are:

https://www.youtube.com/watch?v=qXso8KFG...

and

Graphic card overheating, CPU fan in full speed, then black screen

Haven't tried replacing it yet, but will confirm myself once the part arrives.

Anyone else had joy with a new heatsink?

I inadvertently attached the thermal sensor to the hard disc - the fan now runs flat out with reduced artefacts etc.

Same overheating problems with imac g5 white 24inch nvidia 7300 gt. Smcfancontrol stop it to crash and those graphic detail but aplication like chrome with a few windows opens specially videos running cause those graphic detail errors to come back. for years i suppose it was graphic card problems and i was thinking on upgrade to 7600gt, but the cost of it is too high (300$) i Havn't clean the dust also uncheck the thermal paste in 6 years. i hope this help me, if does i will sell this machine a soon as posible.