Black screen at startup, chimes repeat every two seconds, nothing more

Thanks @alexrobinson. I appreciate that.

Just checked that post. If I read it correctly the feeling was that that machine was crashing/restarting as soon as it started to generate video. (A problem with the GPU as you say.)

With this machine it restarts even earlier. I can’t even get near safe mode or verbose mode etc. It just keeps on chiming with a black screen. Nothing on the keyboard makes a difference.

Am I right in assuming that it will basically need a new motherboard?

Best

David

@davidbaker, my girlfriend had an iMac identical to yours and she had the same issue you're describing, no screen response whatsoever. Even though the guys in the thread I linked said they were able to get some video, it doesn't necessarily mean it's a different issue, it just might mean your iMac is further damaged. I've read that some of these iMacs have problems with thermal management and end up cooking their GPUs to death. However, maybe @mayer would like to chime in?

@alexrobinson Thanks, will address this tomorrow when I'm fresh and mind is sharper.

@davidbaker Did you find out the issue? I've got the same model 27" iMac 2010 with the exact same issue you describe. I'm guessing it's the GPU but would like to hear if you got anywhere with figuring out what was wrong. Do you have any update? Thanks

@fourcandles Sorry for the delay in replying. Yes indeed. It turned out to be the video card. Was fixed for £100 and the iMac is now working fine. Hope that works for you too.

Thanks @alexrobinson too for your help on this.

David