Advice for dealing with a recurrent service issue

[donbach]

Hello,

I wish my first post here at macrumors was under more pleasant circumstances. But, be that as it may, I face the following situation.

My 4 year old BTO 24" imac suffered a second GPU coronary failure yesterday. This machine was ordered with the nvidia 7600GT, 256MB VRAM. The original video card was replaced in July, 2008 by apple tech support under my extended APP coverage.

Now, the same failure (same symptoms as before-herringbone artifacts appear on screen then system freeze) has occurred to the one they replaced. Strangely, the upper case did not feel hot when touched, so like before overheating can generally be ruled out as a culprit.

My question, can anyone please offer me guidance from their own personal experience or knowledge on how to negotiate with apple support? I have a reservation for tomorrow with the genius bar and I would like to believe I have some leverage since this will make 3 GPUs in 4 years.

thanks for reading and this is one great forum community,
donbach

p.s. I followed all the instructions at apple support including verbose logging and zapping PRAM to no avail. Only a white screen which forces me to press and hold the power button to shut down.

 

[redkamel]

hope it all worked out, but at this point I would recommend trying to mind-judo the Genius into replacing and testing a lot more than a GPU...a logic board or PSU

I recommend acting dumb and asking questions/getting them to teach you to get them thinking along that path. Otherwise they would just stamp the paperwork. Its also totally valid to think that you are very likely to have a GPU failure when your warranty ends and you want to get it fixed now while you can.

Obviously it helps to have a nice Genius guy that really nerds out and wants to solve weird problems, and not the clock-in-clock-out kind.

 

[donbach]

Replaced Nvideo 7600GT myself

As the title says, I skipped the apple tech route (out-of-warranty and far too pricey) and bought and replaced the gpu myself. Finding other DIY imac users in the same predicament and their advisory posts & instructional youtube videos on how to open and disconnect the imac's internal hardware to access the video card gave me the confidence to tackle this job myself.

If you have not done so already, I recommend istat widget to monitor internal temps and fan speeds. Any abnormal elevations in temps can then be dealt with pro-actively before a major failure.

p.s. When I had my imac opened up I was surprised by the amount of dust that had accumulated on the vanes of the 3 cooling fans and the back inlet grid. Light vacuuming and my dust buster cleared this mess right up.