Mac mini 2010 : flickering display

Posted: August 14, 2010 in Apple, Troubleshooting
Tags: , ,

The mac mini 2010 produces flickering image on my Samsung SyncMaster 206BW monitor (plugged using the provided HDMI to DVI adapter) : it isn’t obvious overall, however it really shows on some dark gray colors (left side of this site, up and left panes in Garageband). It’s like an old CRT monitor with too low refresh rate. It was ok with the MDD G4 on the same monitor, whatever refresh rate (60 and 70Hz).

Snow Leopard only allows 60Hz on the mac mini (should be ok as it isn’t CRT), and I’m not confident using 3rd party utilities to try to add 70Hz option (some have experienced stability issues or out of range – that requires rebooting in safe mode).
I plugged the power cord on another plug, and also put the LCD display farther, to check for interference problem, however it didn’t help. I also put the original 2×1 Gb ram without success.

I wonder if this is a defect with the Nvidia 320M chipset (or with the added ram, used by the chipset). Usually it comes from a voltage tuning problem when manufacturing the display, and can be detected through inversion test. it was also noticed on some mac book pro. The integrated chipset may so enhance an existing problem.

Update : it seems many people are experiencing flickering problem with the mac mini (varies from monitor vendor, Samsung’s are reported to work bad with the mini). A workaround with previous minis (without HDMI) was to connect to the monitor using VGA (through mini DVI to VGA adapter)… Replacing the mac mini/motherboard many times didn’t work for these people, so they are implying the problem comes from Apple’s driver software (and thus could/should be fixed in a later update) :
http://forums.macrumors.com/showthread.php?t=989930
http://www.ehmac.ca/mac-ipod-help-troubleshooting/80230-flickering-mac-mini-lcd.html

The Samsung 206BW doesn’t seem to allow refresh rate above 60hz at 1680×1050, however some have had good result (with other monitors) using 58 or 57hz (using a third party utility). I tested lower resolutions through Apple’s monitors preferences pane, and some provide additional refresh rates (70 and/or 75hz) : for most, switching the refresh rate higher didn’t fix the flickering issue. Moreover, the 1024×768 resolution didn’t experience flickering, even at 60hz, while the “1024×768 (stretched)” (in fact both modes display stretched image) did flicker whatever refresh rate !

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Comments
  1. As some users had less flickering connecting the monitor through VGA, I bought the Apple mini display port to VGA adapter, and here are the results :
    -the flickering seems gone (at least very slight), particularly on gray tones where the problem was huge.
    -however the image now has a pink tint (on white), and colors (white) are oversaturated (no mean to fix this through ColorSynch settings nor monitor’s settings).
    -the text and controls borders are less sharp.

    Then it isn’t really usable, and I’m stick with DVI and flickering (that at least mainly occurs on gray colors, hopefully not the most used).

    Apple has to provide an update to GeForce 320M chipset driver, as it is likely to be a software problem.

  2. akismet-a7d0c48bc720f8924f9c24e3fbdebe8e says:

    I solved the issue for me with a different monitor first… I was using an ASUS AE278 27″ LED first and it flickered and would go snowy randomly several times an hour… I had an Acer 23″ LED and switch it and it worked great… However, after spending 300 dollars on the ASUS, I wanted to use it… I purchased an App called SwitchResX and it fixed all the problems for me… I checked the second 1920 X 1080 selection on the list of resolutions and all my problems went away….

    Scott

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