Weird wavy line on the right side on my iMac screen

I have a 27" iMac I bought in December 2009. Last year I noticed some vertical lines across the screen. I got the screen replaced and it was fine for a few months, then I notice a darker wavy line on the right side of the screen. It's hard to notice at first, but very visible on a gray background. So I sent it for another repair, but Apple claims they can't see anything and even sent me photos to prove it. They can't find anything wrong. Here's how it looks:


I'm thinking it could be heat because I am physically burning myself when I touch the top right corner, but it's less intensive on the left side. I asked Apple to stresstest it for a week and see if it pops up.

I'm grasping at straws here though and don't expect Apple to find anything and I get sent back a faulty computer.

What do you all think?

Well, the wavy line on the right side is clearly visible on the image you posted. The fact that your iMac is hot on that side is also a concern. An iMac generally runs cool, much cooler than the typical MacBook or MacBook Pro. Why don't you download the free iStats Pro Widget from here and keep track of your fans speeds and temperatures? Let us know what they are when the machine is running hot.

Thanks for the suggestion. I would, but the machine is at Apple repair service. I've told them to keep it running for a week and test it to see if they can reproduce the heat and the wavy line. If they still can't find anything I guess I'll get it back and give it a try myself.

Well, problem solved (for me at least). The stresstest worked and they saw the wavy lines and noticed that the iMac was dangerously hot (I actually have a burnmark on my right arm when I was trying to put in a USB device).

Soon after, someone from Apple called me with 1000 questions about that, whether I am seriously hurt, whether my house was damaged etc. I guess they were afraid I was going to sue them.

Today I got a call from Apple saying that they will send me one of those new shiny 27" iMac's free of charge

AWESOME. Congratulations for taking action before something bad happened, and congrats on getting the kind of service Apple is renowned for!

Not bad for a 4 yr old iMac. Well done, but its my bet when they took it apart, they saw a fault that one of their technicians did when they replaced the screen and to save face, here is a new skinny iMac, but either way, you gotta be happy with that

Wow...pretty amazing! From 2009 to 2013 27" iMac free of charge!!!

- Nick