iMac 2011 not responding to any boot options

[Sheridan]

I was trying to bootcamp a 2011 imac with W7 and OSX 10, but since the initial install all I get on boot is a white screen. No keyboard combinations are recognised (numlock shows no activity) and eventually if you wait long enough the 'No boot device' message appears which is the Windows message for a knackered installation.

 

I did have OSX 10 already on here, but now it seems to be unbootable with any options as the keyboard isn't working. I've tried 3 know working keyboards and nothing.

 

I'm about to write this off as a dead unit unless anyone has any suggestions? I wish apple used a proper bios so you could at least see some life in it!

[3s-gtech]

Can you swap out the HDD and try again? Not too hard in that model, but does need sucker pads and a good set of Torx bits. I suspect that the bootloader is faulty, so pulling the HDD, formatting it then reinstalling from clean will get it working again. Do you have another Mac nearby to grab a copy of OS X or an image from?

[Sheridan]

I'll see if I can swap out the drive and then boot from usb again. I wouldn't have thought a duff drive would affect the keyboard being responsive thought? Although you never know. I've got Sierra on a usb drive to try next!

[3s-gtech]

As it's a UEFI rather than BIOS, and the keyboard is USB, I wouldn't be surprised that it's not initialised until it has gone through at least part of the boot procedure.

[Sheridan]

Hmm new hdd, white screen permanently now. Dead as a very dead thing.

[3s-gtech]

One last try, before defeat (and my Macs have done the same thing, this has fixed it) - is the old PRAM and SMC resets - https://discussions.apple.com/docs/DOC-3603

[Sheridan]

Its doesn't recognise any key press on boot now. Looks like a terminal failure. Off to the scrapyard with this one!

[AntonioRocco]

Don't give up just yet as the problem may be easily fixed as well as being not that expensive?

 

I've seen similar issues to what you're reporting being down to a failed/failing GPU and/or display? Nothing will show on the display no matter what you do with the keyboard or anything else. If you've reset the PRAM and you're not getting a boot chime then odds favour a failing/failed GPU. If you are getting the boot chime probably the display.

 

I think on those models you could attach an external thunderbolt display or SVGA display using either a thunderbolt cable or thunderbolt to SVGA/DVI adapter assuming the display supports both connection types. If you've got some of that gear handy it's worth one last shot. If it works then you're not looking at replacing the iMac itself only the failed part which is going to be your cheapest option.

 

Hope this helps.

 

Antonio Rocco (ACSA)

[GuyJD]

It might be worth checking the memory modules, my imac reverted to just a white screen when one of the modules failed, I took out the failed module and it booted fine on the remaining one.