Repairing iMacs with faulty video cards

I’ve just finished repairing an iMac which started to display the dreaded “vertical lines” – a surprisingly common symptom seen on a wide range of Macs that indicates a faulty video card. Typically that means replacing the entire logic board, which is often prohibitively expensive. But in this case the machine was a “white” 24″ iMac, which has the video card on a separate daughterboard, so a swop was possible.

Because the local Mac repair places in Bristol and Bath were quoting very expensive prices for the part, we got it shipped in from the USA, which worked out a lot cheaper. Replacing the old part is fairly involved, as you have to strip out the screen and logic board, but compared to some iMac repairs I’ve done it was fairly painless. Customer happy, I didn’t lose much blood and it is satisfying to get a perfectly good machine back up and running.

If you do have a Mac that starts to display strange patterns on the screen, you might want to try monitoring the temperature of the video card using a tool like Temperature Monitor, and possibly even force the fans to work a little harder with something like smcFanControl.

Mac behaving strangely? Randomly crashing? Why not give it a little Sweet-Apple?