mac mini and Samsung SA350 contrast issues

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Level 2

341 points

mac mini and Samsung SA350 contrast issues

My Dad has his Mac Mini 3.1 runninfg 10.5.8 connected to a Samsung SA350 using a DVI to vga dongle. There seems to be an issue with contrast or gamma. The practical impact is that it is very hard to see subdued text as is found on many web pages like Yahoo for example. So this is not just aestetics, it impacts the abilitiy to reaqd pages.

If you go to calibrate the settings from system preferences/displays, the procedure has you adjust the contrast and brightness of the monitor while looking at a black target that shold have a grey oval in it. Despite changing the contrast and brightness through the whole range, the target is always black with the Mac mini.

So I tried hooking it up to my macbook pro (also running 10.5.8) and the picture looked great. I went into calibrate and the target looked right and changing brightness and contrast does indeed impact the visbitliy of the oval.

I went back and forth between mini and laptop several times and tried changing resolutions and magically the mini started working right. Went to bed and turned off the computer. In the morning no joy. Bad contrast again. Spent another 30 minutes fiddling and got it to work again, but again lost the behavior after restarting machine.

I suppose getting a DVI to HDMI cable is a possibility, but the fact that it worked at all suggests there is a way to make the vga work.

Suggestions? (I already tried resetting PMU)

thanks

Mac mini, Mac OS X (10.5.8)

Posted on Jul 8, 2012 6:36 PM

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Answer 1

Maxooo

Level 1

0 points

Nov 26, 2012 1:06 AM in response to Joseph Vander

I was in the same situation and I found a usefull software Dimmer. You can use it to ajust the "screen luminosity" (in software not in hardware).

You can download it here : http://www.macupdate.com/app/mac/35000/dimmer

I know it's not a good practice to patch a problem like this but it does the job.

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Answer 2

Joseph Vander Author

Level 2

341 points

Apr 25, 2014 5:47 PM in response to Joseph Vander

This problem persists. I have a bit clearer understanding of what is happening but no idea why it is happening.

Summarizing:

1) A Macmini running 10.5.8 cannot provide a decent picture to a Samsung monitor. No amount of adjusting of the monitor or the display preferences work. Ths image is so contrasty that it is very hard to work with.

2) You can instead connect the Samsung to either my Macbook Pro or my Dad's MAcbook and get a great image on the Samsing.

3) Here is where it gets weird. After plugging the Samsung display to one of the laptops, you can now plug it into the Mac mini and the MacMini is able to provide a great image to the display. You can work with the Mac mini for hours and possibly days with no problem.

4) The minute you restart the MAc mini it is unable to provide a good image to the monitor. You have to go find a laptop and go back to step 2.

Any ideas? Seems like a corrupt system file. Where might I look?

thanks

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Answer 3

den.thed

Level 10

90,946 points

Apr 26, 2014 7:37 AM in response to Joseph Vander

First check, Apple > System Preferences > Universal Access > Seeing Display and make sure that the Enhance contrast: is set to Normal

If that does not fix it, reset the PRAM as per > About NVRAM and PRAM

1. Shut down the computer.

2. Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.

3. Turn on the computer.

4. Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.

5. Hold the keys down until the computer restarts and you hear the startup sound for the second time.

6. Release the keys.

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Answer 4

Joseph Vander Author

Level 2

341 points

Apr 26, 2014 12:20 PM in response to den.thed

Hello den.thed,

After over 18 months I think that the problem is solved thanks to you. I went into Universal Access and did indeed find the contrast was not on normal. This seems to be the solution. I even restarted and things still look good.

I would gladly name my next child after you, but I have three grown kids and am not likely to have more. I can offere you any lottery winnings exceeding 17.3 million. (I get to keep the first 17.3 to be clear).

Thank you!

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Answer 5

den.thed

Level 10

90,946 points

Apr 26, 2014 4:34 PM in response to Joseph Vander

You are welcome! 😉

Hope you hit it big, it would nice to put more into my grandchildren's collage funds.

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