No output to HDMI (but ok to VGA...) after CPU upgrade

Discussion in 'iMac' started by torakiki75, Dec 9, 2008.

  1. macrumors newbie

    Dec 9, 2008
    Hi there,
    I have a very strange problem... hope you can help!

    I wanted to upgrade my Mac Mini to use it as an HTPC, so I passed from 1.83Ghz CoreDuo/512Mb to 2.00Ghz Core2Duo/2Gb.

    The CPU and RAM upgrade process went OK, so I tried to connect the Mini to my HDTV (TOSHIBA 37A3030D) via a DVI->HDMI cable, but the screen was blank.
    I thought I had somehow damaged the digital video out of the Mini during the upgrade, so I tried to plug a 17" monitor with a VGA-VGA cable and a DVI-VGA adapter: no problem there.
    Then I thought about a cable issue, but the very same cable works perfectly when I try it with my MacBook Pro, and in the same TV.
    So I played a little with SwitchResX and finally resolved: after few tries and some reboots everything worked.
    But then I noticed that CPU temperature was a little too high, so I decided to re-open my Mini and put a better thermal compound.

    All went well, or so it seemed: in fact since this last intervention the CPU temperature went ok but I couldn't get HDMI output from my Mini any more!!
    Output to VGA still works, tried with the monitor I mentioned before and with my TV's VGA input ... too bad I can't reach 1080i via VGA!.

    I tried almost everything:

    - Playing around with SwitchResX, with no luck this time...

    - Resetting PRAM and NVRAM with various methods (the little button on the motherboard, CMD-OPT-P-RE during the boot, etc... )

    - Resetting SMC

    - Resetting firmware (keeping the power button pressed when turning on the machine 'till it beeps)

    - Reinstalling Leopard results.

    The weird thing is that if I VNC to the mini I notice that the TV is correctly recognized (screenshot:, and EDID data seems ok (link:

    Do you guys have any idea?

    Thank you so much, I'm getting desperate :(
  2. macrumors 6502a

    Aug 15, 2007
    I find that DVI to HDMI on anything even PC's is such a pain in the ass. I have a MINI that I also use as a HTPC and I pulled my hair out for weeks on in trying to get that stupid HDMI to display correctly I tried SwitchResX all that stuff to no avail. So I ended up hooking it up on another tv through DVI>VGA and it picked up the res right away with no problems. I would just stick with DVI > DVI or DVI > VGA if I was you, it's a much better solution IMO.
  3. thread starter macrumors newbie

    Dec 9, 2008
    That's what I'll surely do when I surrender... but still I don't want to!

    What drives me crazy is that for a few hours I could get perfect output to HDMI!!
    Then, for some misterious reasons I never got right again...

    I fear for an hardware failure, but I don't know how to diagnose it.

    Despair continues :mad:

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