Between 2007 and 2008, some MacBook Pro (s aapl) models shipped with faulty Nvidia (s nvda) GeForce 8600M GT graphics processors, which can cause blank screens or image distortions. Apple acknowledged the issue and offered to repair affected units in October 2008, but a recent report suggests those problems aren’t completely behind the company.
The tool Apple uses to determine whether or not a defective Nvidia GPU is responsible for your MacBook Pro’s problems might not be accurate in a number of cases, according to Mobile Magazine. Apple evaluates machines for the problem using a USB stick running Nvidia’s diagnostic software. Once the drive is inserted, it runs tests and provides printed reports on the nature of the problem. However, the test may not be returning accurate reports in every instance.
In some cases, according to Mobile Magazine, the faulty GPUs can overheat, leading to a short in your logic board when heat-transfer material ends up on parts of your computer’s internals where it shouldn’t be. That would lead to a diagnostic result indicating the logic board had failed, not the GPU. Logic board failures entail a non-warranty repair that can cost more than $1,000.
Mobile Magazine describes one specific case in detail where this occurred, but a call to Hi-Tech Electronics, the shop which performed the diagnostic and repair in question (it replaced the faulty GPU and cleaned the logic board for $260 including shipping, instead of the $1,000 Apple was asking) confirmed it has seen many similar cases, and continues to repair multiple MacBook Pros with problems stemming from the same issue each week.
Apple couldn’t be reached for comment as of this writing. If these reports are accurate, a simple fix would be to open up and inspect the internals of any MacBook Pros potentially affected by faulty Nvidia GPUs, rather than simply performing a software diagnostic test using a USB drive. It would be more costly and time-consuming, but also probably better for customer loyalty in the long run.