2011 i7 iMac Power Up Woes

[DrewJW]

Hi all.

Firstly lovely forum, and I hope to settle in and help where I can.

I have a problem however, I have a 2011 i7 iMac with the 2gb 6970m and 1TB HD.

A few days ago while playing EvE Online in bootcamp, I went for a coffee and came upstairs to a powered down iMac. It would not respond to the power button being pressed, and even after replacing the fuse the computer showed no signs of life. Their was no smell, or noise from inside the computer it just sits as if their is no power at all.

I am out of Applecare on it, and suspect a logic board failure after a chat with Apple.

However, is their anything I can try to see if it could be something else?

Thanks

 

[DrewJW]

Today I tried some advice I read about, I changed the powercord to a known working one.

Holding down the power button, I removed the powercord, and while still holding down the power button I put the powercord back into the iMac and it fired up!

However no visual ( not even on external ) no chime, and the fans just go to maximum RPM. This situation remains the same, I hold power to shut down and it does. If I then hit power again it resumes to the same status as above ^

If I remove the powercord totally and then reinsert without holding down the power button, the iMac resumes ignoring all attempts at powering up.

Any longshot ideas be great, as it's out of Applecare, and really I need this computer working...

 

[DeltaMac]

...
Holding down the power button, I removed the powercord, and while still holding down the power button I put the powercord back into the iMac and it fired up!

However no visual ( not even on external ) no chime, and the fans just go to maximum RPM. This situation remains the same, I hold power to shut down and it does. If I then hit power again it resumes to the same status as above ^

...

Don't do that! (don't insert power cord while holding the power button.)
http://support.apple.com/kb/TS1433

Your original post is likely the most relevant (your iMac powered off by itself)
Try both the SMC reset, and a PRAM reset. If your iMac still refuses to start up, then I suspect that you have a faulty power supply. There's enough power to get the fans to run, but not to power up the system.

 

[DrewJW]

Don't do that! (don't insert power cord while holding the power button.)
http://support.apple.com/kb/TS1433

Your original post is likely the most relevant (your iMac powered off by itself)
Try both the SMC reset, and a PRAM reset. If your iMac still refuses to start up, then I suspect that you have a faulty power supply. There's enough power to get the fans to run, but not to power up the system.

Joy of joys beyond me to afford that at the minute ( gotta love today's job market)


Thanks will just have to pack it away for now then till better financial times.