External Samsung LCD Issue With Unibody MBP

Discussion in 'MacBook Pro' started by mct74, Nov 10, 2008.

  1. mct74 macrumors member

    Aug 15, 2008
    Sorry in advance for the long post. I have found a few threads about external display issues on the unibody MB's, but not on the MBP. Here is the issue I have had and what I found. hopefully it saves someone time in troubleshooting this problem:

    I have a 2.53Ghz (late 2008) unibody MBP hooked up to a Samsung Syncmaster 206BW LCD. While using the nvida 9600 (better graphics mode), I have no problems. However, when I switch to the 9400 (better battery mode), the external LCD blanks out for a second every 5 - 20 minutes or so.

    I then brought my MBP to my office where I have an Optiquest Q20wb monitor. I hooked it up and sure enough, I did not have the screen blank out the whole day.

    I checked the display settings and found an interesting tidbit - the Optiquest screen has a refresh rate of 60, where my Samsung Syncmaster 20" LCD at home shows up with a refresh rate of 59.9 (even though when I use my Mac Pro tower it shows up with refresh rate of 60). Both LCDs have the same resolution of 1680 x 1050, so I was thinking the problem stems from issues in compatibility with the LCD and the 9400 video card.

    So I decided to go to the Apple Store to do some testing with a Genius with my laptop and my Samsung monitor. We hooked up my late 2008 MBP laptop in the store to the Samsung 206BW LCD and after 15 minutes, it blanked out. I told the Genius that the issue does not seem to be present with my Optiquest LCD so nVidia driver compatibility with the Samsung LCD is looking most likely.

    We then decided to hook up the Samsung LCD to another MacBook Pro in the store to see what would happen (a display unit). With the 9600 card activated, the monitor performed fine. However, when we changed to "Better Battery Life" mode, activating the 9400 video card, caused the MacBook Pro to actually crash and reboot!! When it came back up, the video card setting was set back to "Bettery Graphics Performance". We checked the installed updates on the MacBook Pro and the one in the store did not have the MacBook Pro 2.1 update which fixes compatibility issues with some external displays.

    It is apparent that the 2.1 update helps the laptop not crash when the 9400 card is activated while hooked up to a Samsung 206BW LCD, however, it is also apparent that the update does not solve all the issues with compatibility, as the refresh rate is detected incorrectly (59.9 instead of 60) and the screen blanks out intermittently as a result of what looks like the video card sending a refresh rate that is out of range of the monitor's capability.

    They took my information and are going to escalate the issue to the engineers to hopefully get a fix pushed out as this may also affect other LCD's that are based on similar components as the Samsung displays.

    Bottom line - don't bother swapping laptops if you are experiencing this issue on your external display. Hopefully a software update will be out soon. I urge you to call Apple Support, however, and report the issue so that they can get an update out faster.

    For those asking why would you even need the better battery life mode turned on when using an external display since you are obviously near a power source? Well - sometimes you come in from an appointment where you had the power saver mode on and want to just get to work without logging out and closing all your apps. It is a pain to have to log out just to switch to a GPU that does not blank out on you. Oh yeah - besides that - when you pay $2500 - $3000 for a laptop, you just want the stuff you paid for to work. ;)
  2. Steve686 macrumors 68040


    Nov 13, 2007
    US>FL>Miami/Dade>Sunny Isles Beach>Condo
    I have the Samsung 226BW but haven't bothered to hook up my UniMBP to it because I like the LED so much and 15.4" of screen compared to my white MB with 13.3" screen.

    If I get around to getting an adapter to the monitor, I'll post here what the results are with the 226BW versus your 206BW.

    Truly a great LCD display, otherwise.
  3. clyde2801 macrumors 601


    Mar 6, 2008
    In the land of no hills and red dirt.
    display port problem

    I had a unibody MB and MBP hooked up to my gateway 21" lcd, and used a mighty mouse. Depsite fiddling with tracking, my cursor kept jumping and moving erratically on the gateway. I took the MB back to the apple store, and they informed me the problem must be with my gateway LCD.

    I asked them how they could explain how my gateway performed perfectly fine with my g5 power mac, mac mini core duo and iMac core 2 duo, all running 10.5. The genius tried to pass it off as a problem with my display's refresh rate and shrugged it off.

    I think it's got something to do with the display port technology in the new models. It's the only unexplained variable in the equation.
  4. bay2sacto macrumors member

    Nov 6, 2008
    I too have seen some random weird issues with my MBP 2.53Ghz and external Samsung 216BW. when coming out of sleep, when I open the lid my external LCD will sometimes act like it has no siginal. It has also once or twice just had static snow (like a tv). Both issues were solved by unplugging the external from my MBP & plugging it back in. I had thought it was just me and maybe it was related to the mini display port to DVI adapter. I don't remember which GPU was being used at the time. I think maybe the 9400 cause that's the one I use 90% of the time.
  5. FCDP macrumors regular

    Nov 16, 2007
    Toronto, Canada
    Finally, I've found someone who also has this issue. I'm using a Samsung 2253BW and have the same issue. Upon connecting to an already running MBP or waking up from sleep, the monitor will display white noise static for a few seconds then return to normal. Other times it will display a black screen as well. This is while running the 9600, haven't had a chance to test with the 9400.

    I took my MBP into the apple store, and we couldn't reproduce it on any of the in-store displays. They assumed it may be an issue with my mini-display to dvi adapter, so they swapped it, and I've still had this happen a few times, although less frequently.
  6. FCDP macrumors regular

    Nov 16, 2007
    Toronto, Canada
  7. mct74 thread starter macrumors member

    Aug 15, 2008
    While those are troubling issues that need attention, those symptoms are not what I am seeing and what this thread is about. I actually posted my findings in one of those threads and was told to take my experiences elsewhere and start a more relevant thread (hence why I started this Samsung-specific thread which relates to the screen blanking out once every 5 - 15 minutes when using the 9400 video card).

    So far the issues in that other apple thread you linked to appear to cause odd video artifacts (fuzzy lines, screen flicker, etc.). None of those things are happening to me on the Samsung LCD. The screen looks perfect, it just blanks out when the laptop seems to send a refresh rate that is out of limit for the LCD.

    Regardless - Apple has some serious external display compatibility issues that need correcting. Luckily the 9600 card seems to work fine.
  8. bay2sacto macrumors member

    Nov 6, 2008
    Had a new weird issue. I unplugged my external and closed the lid to my MBP to sleep it so I could take to the other room. When I brought it out of sleep, It hadn't properly switched to the MBP lcd and I couldn't access and dialogs, cmd-tab apps, etc. I tried to switch the main screen back to the LCD which got me my menubar back but still couldn't access and dialogs, etc. So I tried bringing my MBP back to the other room and plugging in my external. No go. I ended up having to do a hard shutdown. After rebooting my MBP trackpad didn't respond to tap clicks. I had to unclick and reclick the option in the sys perferences. This was using the 9400 GPU. It also hosed my Flock install.

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