27" 2012 imac - screen stuck @ 640x480 resolution

Discussion in 'iMac' started by macuserau104, Feb 23, 2013.

  1. macuserau104 macrumors newbie

    Jan 31, 2012
    just unboxed my new 27" 2012 imac - after a 6 week wait for it to arrive.

    first thing i did was run time machine to back it up on a new external 3TB HD.

    it went to sleep during this and when i the screen opened up again the resolution is now stuck @ 640 x 480 i have tried all i can think of to resolve this with nil result.

    i cant contact apple as it is the weekend here (australia) and have done a few searches on the net with no result

    can any one help ?
  2. harlex macrumors member

    Nov 23, 2011
  3. lali macrumors regular

    Oct 14, 2007
  4. macuserau104 thread starter macrumors newbie

    Jan 31, 2012
    more info

    thanks for the help

    have been using 10.7.5

    mew mac shipped with 10.8.2 - tired restart, nil result

    display pref only allows either:

    - best fo display / scaled - it is stuck on best for built in display and if i choose scaled is back to best for built in display when i open it again
  5. drambuie macrumors 6502a

    Feb 16, 2010
    What's weird is that 640 x 480 isn't an available option. The smallest scaled resolution is 800 x 600. It's like you have no video drivers installed, and it's fallen back to the VGA default of 640 x 480.

    I notice you mention 10.7.5. I hope you didn't install that on your new iMac, as you would then have no drivers for the nVidia 6XX GPU.
  6. seanm9 macrumors regular

    Dec 29, 2007
    Cape Cod, MA
    I had a similar issue, try booting from the recovery partition... if the resolution is still the same it may be a hardware failure... also if you haven't reset the SMC and Zap the NVRAM...
  7. WilliamG macrumors G3

    Mar 29, 2008
    I'd do a complete wipe of the system at this point, and reinstall the OS. Just start from scratch. Something software-wise got a little screwy, that's for sure.

Share This Page