Apple on Friday began a new program to replace faulty graphics cards found in some mid-2011 to late-2012 iMacs.
The program covers systems with AMD Radeon HD 6970M video cards. Those were found in the 27-inch iMac models with either the 3.1GHz or 3.4GHz quad-core Intel i-series chips.
According to support language, the video cards could fail, "causing the computer display to appear distorted, white or blue with vertical lines, or to turn black."
That iteration of iMac was sold between May 2011 to October 2012.