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#1 2015-03-23 19:01:01

mcdermd
Member
From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
Website

2008 iMac Graphics Card

I have a 2008 24" iMac with the 512 MB Nvidia GeForce 8800 GS video card. As is typical, the card went bad. It's done this couple of times in the past and I've been able to shock it back to life with a toaster-oven reflow of the MXM card. It went out again last week and the patient was finally all-dead.

nn8sjn.jpg

The cards are about $300 on eBay. There's no way I'm going to spend $300 on this machine. I did find a BIOS, PC version that had exactly the same board for $100. The difference was the replacement had a green board and had a GeForce 8800 GTX welded on. The 8800 GS is really a GTS which is really a GTX that's been neutered so I had good hopes that the ROM firmware would work fine on the new card and since the actual PCB was the same, the heatsink would fit.

fc8hlf.jpg

I physically swapped the flash ROM chip (circled), installed it and it fired right up. The gamble paid off. The iMac lives again.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#2 2015-03-23 20:38:09

macdrone
Member
From: Rainier, Or
Registered: 2014-05-25
Posts: 246

Re: 2008 iMac Graphics Card

Your crazy good at that stuff. 

Does the card show up as the non gimped version in the profiler?

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#3 2015-03-23 21:21:11

mcdermd
Member
From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
Website

Re: 2008 iMac Graphics Card

No because the ROM is what tells OS X what the card is. Theoretically, you can craft a ROM to identify itself as anything you want. I think all the extra pipelines that are disabled on the GTS should be used once the process is offloaded to the GPU, though. That should all happen independently of the ROM.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#4 2015-03-23 21:35:29

techknight
Member
Registered: 2014-05-22
Posts: 453

Re: 2008 iMac Graphics Card

Ive done the same thing with LCD TV main boards. Three or four different TVs different panel sizes all use the same main, find the cheapest main and change the firmware.

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#5 2015-03-23 22:14:45

bbraun
Member
Registered: 2014-05-29
Posts: 1,064
Website

Re: 2008 iMac Graphics Card

Yeah, essentially the same thing with the 64MB PCI Radeon 7000's to get 1920x1200 DVI on System7.  smile

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#6 2015-03-24 00:16:04

techknight
Member
Registered: 2014-05-22
Posts: 453

Re: 2008 iMac Graphics Card

I remember way back in the day I obtained a radeon 7000 AGP, and that card was horrible at rendering games. I remember trying to play GTA3 and GTA:VC and had issues. The Voodoo card worked much better.

But eh. ;-)

Last edited by techknight (2015-03-24 00:16:22)

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#7 2015-03-24 01:02:06

bbraun
Member
Registered: 2014-05-29
Posts: 1,064
Website

Re: 2008 iMac Graphics Card

Yeah, I dunno about games, but it lets me have lots of screen realestate for coding, since the 7000 PCI was the last with a system7 compatible ROM.

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#8 2015-03-24 01:55:28

dougg3
Member
Registered: 2014-05-27
Posts: 28

Re: 2008 iMac Graphics Card

I tried this once and failed with a 20" 2008 iMac and a Radeon 2600. The problem with the 2600 was that I couldn't find a PCB similar enough. The closest match I could find didn't work after swapping the ROM. The one you found looks like a perfect match. Congrats on getting this one to work!

Last edited by dougg3 (2015-03-24 01:57:00)

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#9 2015-03-24 05:32:36

mcdermd
Member
From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
Website

Re: 2008 iMac Graphics Card

Yeah but I feel so dirty for paying $100 for such an old card. big_smile


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#10 2015-03-24 06:18:15

markyb
Member
From: Aurora, OH (330)
Registered: 2014-05-16
Posts: 185
Website

Re: 2008 iMac Graphics Card

Ewwww old 4-digit nVidia models!
*shudders*


http://markyb86.weebly.com for some packs of old macintosh wallpapers, desktop patterns, windows wallpapers, sound files, etc.

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#11 2015-03-24 09:14:04

volvo242gt
Member
From: Duvall, WA
Registered: 2014-05-22
Posts: 410
Website

Re: 2008 iMac Graphics Card

I'm not sure what it is, but, almost every single nVidia card I've come across has failed.  Doesn't matter what model or if it's for Mac or PC.  They just seem to crap out more frequently than the ATI chipsets... 

The nVidia AGP video card that was in my G4 DA blew up spectacularly one day in 2009.  Luckily, I had a parts G4 DA with a Rage 128 Pro in it.  Took that, popped it in, violia, computer worked again.  My old Dell Inspiron 8600 (early non-cost-reduced version) came with a nVidia GeForce 5200 or something similar in it.  Powered up the machine, got a white screen, then, eventually a partially normal screen with artifacts everywhere.  Popped in a NOS ATI Radeon 9600.  Rock solid for the 2.5 years I used the machine, part of that time as my main machine, when the G4 was just too inadequate to use as a main computer anymore.  Then, my father's Latitude D830 developed the black screen syndrome.  On an external display (the one I now use with my Mac Pro), it'd show video, but was green.  Put the computer into diagnostics mode, internal screen showed the correct colors.  Dying Quadro NVS 135M chip... 

So far, the D830 that I just sold off to a guy who had his D820 die on him, and my mother's D830 have been fine.  Mine every once in a while would show artifacts on the screen if I was playing a game, but usually was fine.  Both machines, however received new thermal paste, and mine also received the 2.6GHz T9500 Penryn upgrade, which, unlike what Cory said, did cause a major drop in temperatures.  The other one still has the T7500 Merom chip in it.  Need to upgrade both it and my father's current D830 to the T9500 chips.  His current machine has the GMA X3100 chip and runs very hot, not unlike my old A1181, except much hotter, since it has the T7700, whereas my A1181 had the T8300.  Not uncommon to see the CPU temps around 150-160 deg F on it currently.

-J


modern: Mac Pro 2.8GHz 8-core 6GB/500G/DVD-RW, Mid-2010 A1286 MBP
PPC: G3/400
Pre-Mac: //e
other: iPhone 6s 128GB Space Gray

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#12 2015-08-10 01:57:00

iMic
Administrator
From: Adelaide, Australia
Registered: 2014-05-12
Posts: 948
Website

Re: 2008 iMac Graphics Card

Of course the 8800 GS in one of my 24-inch iMacs has failed now as well, so I may be looking to do something similar to what mcdermd did here.

I'll attempt to reflow the card first. I'm not sure where the BGA crack has occurred, but if it's below the package I'll attempt to flood the BGA with flux before the reflow. If it's between the package and the die, that won't be possible.


Resident Professor of Alternative Methodology
Faculty of Electronic Restorations & Modifications - "It works, let's fix it!"

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#13 2015-08-10 04:48:57

mcdermd
Member
From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
Website

Re: 2008 iMac Graphics Card

A toaster oven reflow worked on mine probably three or four times before it was dead-dead.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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#14 2015-08-10 12:42:46

TheWhiteFalcon
Member
Registered: 2015-04-27
Posts: 504

Re: 2008 iMac Graphics Card

I actually had a Quadro 290 something fail in a work machine a few weeks back, first time I'd dealt with that. Some custom HP model with a custom HP output on it, common fail apparently. Never seen an ATI failure.

And...the 440Go in my 17" AlBook did melt to the heat sink, so...

Last edited by TheWhiteFalcon (2015-08-10 12:43:23)

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#15 2015-08-10 13:12:44

iMic
Administrator
From: Adelaide, Australia
Registered: 2014-05-12
Posts: 948
Website

Re: 2008 iMac Graphics Card

mcdermd wrote:

A toaster oven reflow worked on mine probably three or four times before it was dead-dead.

I'm curious to know how you went about using a toaster oven to do the reflow. I have a toaster oven, but it has absolutely no temperature controls. Only three settings of (currently) unknown heat.


Resident Professor of Alternative Methodology
Faculty of Electronic Restorations & Modifications - "It works, let's fix it!"

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#16 2015-08-10 16:15:33

ClassicHasClass
Member
From: Electron Alley
Registered: 2014-05-26
Posts: 1,118
Website

Re: 2008 iMac Graphics Card

Mine does Top Brown only, and only if it feels like it.


Machine room (updated for 2019!): http://www.floodgap.com/etc/machines.html

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#17 2015-08-10 16:34:39

mcdermd
Member
From: Corvallis, OR
Registered: 2014-05-12
Posts: 1,022
Website

Re: 2008 iMac Graphics Card

The one I use has a digital temp control and a "Convection Bake" mode I use. My method is very un-scientific. Flood the BGA with liquid flux, warm up to 350F for 2 minutes then bake at 425F for four minutes or so.


Daily Drivers: 27" iMac 2.8 GHz Quad-Core i7 (Late 2009), 21.5" iMac 2.7GHz Quad-Core i5 (Late 2013), 11" Macbook Air 1.6 GHz i5 (Mid-2011)
See the restored heroes here.

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