iMac with 4K Seiki Help

Discussion in 'iMac' started by dcameraman, Dec 12, 2013.

  1. dcameraman macrumors newbie

    Dec 12, 2013

    This is my first post in the forum. I just got a Seiki 55" 4k TV and I am trying to get my iMac to use it as a second display. I have the Accell Active mini-DP -> HDMI adapter and the computer recognizes the external display at the correct resolution. But the tv won't display anything. My iMac is a Late-2012 27" with all the max hardware config from apple.

    Any help?
  2. houkouonchi macrumors regular

    Oct 31, 2005
    Are you getting 'no support' or is it just black? It should work with that adapter. What I would try if you haven't already:

    1) The adapter hooked up to another computer to see if it works on another machine.

    2) The adapter hooked up to another display or seeing if you get anything lowering the resolution to 1920x1080 vs 3840x2160.

    3) Try a different HDMI cable. There have been several reports of getting a bad HDMI cable from seiki. One I got on one of my 39 inch seiki's ended up being unreliable and lost sync often but still somewhat worked.
  3. dcameraman thread starter macrumors newbie

    Dec 12, 2013
    1) Tried the whole setup on my 2011 iMac which is decently spec'd and nothing. The TV says unsupported format and stays on the blue screen.

    2) I tried it on a TV that is less than 1080p res and it worked. The only resolution choice when plugged into the Seiki TV is 3840x2160. there are no other options to choose.

    3) The TV is a little far from the computer. I use a 35 foot HDMI cable to reach it properly. If the cable works with a lower res on another TV would it still be possible that it wouldn't work with 4k because of an unreliable cable?

    I appreciate your response. Thank you!
  4. Trixster macrumors member

    May 18, 2009
    I´m unfamiliar with your specific tv but I would assume it lacks support for 4k through HDMI. As that is fairly common on 4k tv´s atm... honestly, I don´t think there´s any 4K tv´s out there that supports 4k through HDMI yet.Your only choice is to use DP in both ends.
  5. dcameraman thread starter macrumors newbie

    Dec 12, 2013
    I appreciate your comment but the TV does state that it supports 4k through HDMI
  6. unfrostedpoptar macrumors regular

    Jan 29, 2010
    Yes - I got the 39" Seiki a few days ago. I mostly love it and works great with my 2012 15" rMBP (both from built-in HDMI port and using Accell mDP->HDMI adapter).

    I have had some problems - most when it goes to sleep and I turn it back on - where I sometimes see the "Not Supported" message or it comes up in something like 640x480! Usually, unplugging the HDMI cable and plugging it back in fixes things with it coming up in 3840x2160@30Hz. However, a few times, doing this caused hard re-boots of my Mac :(

    Not sure how to debug this - or what you're seeing. I'd bet it's the Mac drivers but doubt there's much users can do about this.

    Hope you get it working. I calibrated the colors last night with a Spyder4Pro and it looks pretty great. I'm sure the new Sharp, Dell, Asus are probably better, but they're also at least 3 times the price.
  7. dcameraman thread starter macrumors newbie

    Dec 12, 2013
    I've tried all of that. Thank you though. Maybe there will be an update soon for better support.
  8. jediDev macrumors regular

    Jun 13, 2012
    Have you tried it using a shorter HDMI cable (presumably this would require moving the TV or the iMac temporarily). That at least would give you some insight as to whether the problem was the cable.
  9. rittchard macrumors 6502

    Aug 12, 2007
    I'm presuming you already tried this but just in case, did you already try upgrading the Seiki firmware to the latest version? I had trouble getting a PC to work with mine until I did that.
  10. dcameraman thread starter macrumors newbie

    Dec 12, 2013
    I have not tried that. I will do so tomorrow!


    I haven't. I just checked Seiki's firmware page and they don't have am upgrade for the 55inch 4k. Just the 39 and 50. Maybe a google search could reveal more. That's a good idea though.
  11. Vedia macrumors newbie

    Apr 1, 2005

    Is my late2012 iMac (13,2 model) compatible with 4K TV?

    What would I need to output 3840x2160p out of my late 2012 iMac?

    Thanks! :apple:
  12. fa8362 macrumors 65816

    Jul 7, 2008
    No iMacs, past or present support 4K display. Period. 2560x1440 is the resolution limit.
  13. Vedia macrumors newbie

    Apr 1, 2005
  14. fa8362, Aug 7, 2014
    Last edited: Aug 7, 2014

    fa8362 macrumors 65816

    Jul 7, 2008
    That page must have been updated recently, because I looked at it a week ago and there was no mention of any iMac, only the 2013 Mac Pro and the late top priced retina mac book pro.


    I don't see how an adapter can change anything. The mini doesn't even have a video card, just built in video that isn't capable of 4K display at any usable refresh rate.
  15. Vedia macrumors newbie

    Apr 1, 2005
  16. omvs macrumors 6502

    May 15, 2011
    Well, I'm sitting in front of a 2011 27" driving a Seiki 39". What it can't do is drive at 60hz on a single connection, though the seiki doesn't support that either, so I live with 30hz on this setup.

    It will not work without a active adapter though - I have a passive HDMI 1.4 adapter and the drivers kick it out as an invalid mode.

    I'd expect the 2012 imac to work, but thats a configuration I haven't tested. The models I have seen not work are those with old intel integrated video (HD4000) like the 2012 mini & the macbook air.
  17. Vedia macrumors newbie

    Apr 1, 2005

    Thanks! So the only thing I'd need is the Accell Active adapter?

    I presume if an old Intel HD4000 works, the newer Nvidia GTX 680MX will work as well.

    Still waiting if someone with a late2012 iMac can confirm that it can manage 4K TV...
  18. omvs macrumors 6502

    May 15, 2011
    Actually, the intel doesn't work (one of the few exceptions I've run into). But a GTX 680MX *should* - my rMBP has a GT650 and that works fine.

    With a discrete GTX 680 (macpro4,1), I have driven 4k x 30 hz out the HDMI and 4k x 60hz out the displayport. not exactly the same as your imac, but i'd think it'd be using the same driver. Unfortunately the card's displayport is full size, or I would test the the mDP->HDMI adapter on it.

    So yes, I'd expect all you'd need is the adapter, and of course a reasonable HDMI cable. The one's seiki ships have worked fine for me.
  19. Vedia macrumors newbie

    Apr 1, 2005
  20. Chippy99 macrumors 6502a

    Apr 28, 2012

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