2011 Imac resurrection graphics card.

terramir

macrumors newbie
Original poster
Apr 6, 2009
26
0
Los Angeles
OK I got my hand on a 2011 imac for 10bucks :) however it's got a green bar problem the mac store told me the hdd fan has some sort of problem , but according to the rpm still spinning. And the video card failed. They won't work on it because it's too dirty inside (history).
This machine is sweet though, 16gb ram 2gb HDD 3.4 ghz processor and a 6970 graphics card.
Now I seen some things online about baking it, then I saw something about it not being reballing it but chip internals that can be fixed by heating it to 120C and not 200C, well I dunno if it's the case with the 6970 gpu 2gb BTW. Anyone here have some insight with this particular gpu??.
Thinking about replacing the HDD with a 850 pro samsung ssd 256 gb since that should make it quite snappy. I got one of those I can replace with a 240gb mushkin eco2 that would use less power in my lappy anyway.
Since there is no guarantee the baking will work does anyone know the cheapest possible route to get this back in working order, I would not mind sacrificing the boot screen, although I would love knowing if there is any "windows" card that is known to be flash able and is significantly cheaper, because I really don't have the money to spare. I would not mind a slight hit in performance I wonder if there are any Nvidia cards that are newer but lower end that would come close but much cheaper.
terramir
 

terramir

macrumors newbie
Original poster
Apr 6, 2009
26
0
Los Angeles
there are gtx 570 and gtx580 cards that can be flashed to work with efi, what about the 570m and 580m cards does anyone know if those are hackable?
terramir
 

Lucas Godfrey

macrumors 6502
Jul 12, 2010
306
88
Somewhere between Here and There
The iMac has a MXM slot for the graphics card, I've not heard of any third party solutions for replacing the card. You may just need to have the card reflowed (hint: do not bake.) or replace it with the same card from ebay.
 

b06tmm

macrumors regular
Jul 23, 2009
236
23
South Louisiana
Having just encountered this issue with my mid-2011 27" iMac, I decided to go with the "oven" method for my 6970 video card. I took the average of what people did online and decided to bake it at 200C for 11 minutes. I also cleaned out all three fans and used K5-PRO for thermal paste.

I mangled the LVDS cable to the main-board upon reassembly so had to wait until today to put it back together. I also zeroed out the drives thinking of parting it out if the new cable didn't work, so that's why I'm reinstalling the OS.

I'm happy to say that I'm here now!



This machine has been on 24/7 since I bought it and will update this if the card fails again.
 

terramir

macrumors newbie
Original poster
Apr 6, 2009
26
0
Los Angeles
Thinking if I get it running to also drill a bunch of holes right by the graphics sink maybe even add a small fan on the outside suckling air out depending on the Temps will use a decent pattern just so it also looks good in case I decide to sell it later after I fix it.
I can 3d print a fan shroud. If needed.
But short of finding a card with a 6870 chip and flow it off and flow it on. Leaving the 6970 chip on there without doing some sort of cooling mod is bound to end back in the fried zone eventually. If I see enough room to add a fan internally to force the heat out of the sink and to the vent the only thing I will need to find is some power to power the fan. As other peeps have stated 70 C all good 90C that 6970 chip is ship p=t if you get my drift.
but really if I could find a stable gpu that can be efi modded that would be better though cause I would love a fully working mac.
terramir
 

b06tmm

macrumors regular
Jul 23, 2009
236
23
South Louisiana
My fans were really dirty and by cleaning them I'm sure I improved their cooling ability greatly. I also installed smcFanControll and can boost the fans any time I see the temps rise too much.
 

WaferGuy

macrumors newbie
Aug 22, 2017
8
2
For those who have a mid-2011 iMac with Sierra (10.12), do you see fan speed increase when ODD shoot up above 70C?

My ODD fan stays at 1150 rpm even ODD temperature reaches 80C! I have to use "Macs Fan Control" to adjust fan to 2700 rpm. Then, temperature comes down below 70C.

I wonder if we are seeing a (Sierra) SMC software bug in mid-2011 iMac machines!?
 
Last edited:

Redlight-Records

macrumors newbie
Nov 10, 2018
18
2
The Basement
I also have an oven-baked undead zombie 6970m. But I know it won't last.
So lets say that there are more than a few poor 2011 iMac owners that for whatever reason either can't or won't go through with the bold move of installing an NVIDIA replacement. That leaves only one choice, right? get a re-ball off ebay. Which is not a comforting thought made even less comforting by the fact that for every listing, you're not entirely sure if it's:

1. an original card that's failed already and been baked.

2. an original card that hasn't failed. yet.

3. an Apple replacement card that's failed already and been baked.

4. an Apple replacement card that hasn't failed. yet.

5. an unbranded knockoff

Which leads me to these important questions.

A. Is there a way to tell the difference between the original 6970m's and the ones Apple supplied as part of their much-too-short recall? Or did they just replace a defective card with another identically defective card?

B. Is there a way to spot an unbranded knockoff?

I want to know:

are there certain makes of the 6970m cards that have a lower probability of failure?

Looking through pictures of 6907m listings on ebay you see some with the BLACKCOMB tag on the left or right in big or small text or not at all. Some have an additional HF / e l mark on there as well. As for the chip itself, some have a clear AMD brand silkscreened on them and some don't. Some are made on black, brown or even blue PC board. Some sellers include the tag "Bespoke" as part of the item information. All that I've seen have either 109-C9657-10 or 109-C9647-00 screened on them, but it doesn't differentiate the memory size so I'm not sure what the difference is.

Does anybody out there know what, exactly, a legitimate 6970m should/shouldn't look like? and if those markings and appearance could lead a buyer to get a make that had the best chance of survival.

I've posted some screen shots of some of the variances between card images. These are all listed as: APPLE IMAC 27" A1312 Mid 2011 RADEON HD 6970M 1GB GPU VIDEO CARD

except the last one listed as a 2GB