Mac Mini DVI display problem

olivier.marian

olivier.marian

Registered
Hello,
Just bought a Mac mini 10 days ago.

When plugged into my Viewsonic 21', I have a problem: strange lines of red dot blinking when there is some activity, for instance when moving the mouse over the dock which makes the zoom effect.

I saw on the Internet that I am not alone with this problem.
My viewsonic works perfectly with other computers I have at home.
This is a different problem than the one about DIM display when using the VGA adapter.

I saw that some people solved this problem using using ATIccelerator, a little free utility that you can find here:
http://thomas.perrier.name/software/ATIcceleratorII.html
or
http://mapage.noos.fr/campahunta/software/Graphiccelerator.html
some people where happy when DOWNCLOCKING the ATI card with this tool...
PLEASE SEE DISCLAIMER BEFORE USING IT

Anyway this did not work for me.

It seems to be a Firmware-hardware related problem.

Any help is welcome !

Olivier
 
My main monitor is a viewsonic 201s DVI, my second is not DVI so I can't try.

I've read on the Net that the Apple Cinema Display works well... ;-)
More than the price of the mini... not really what I planned... I'd rather find a solution.

I have an opened case with ATI, I probably should open a case with apple also but the Net forums are full of people with silly replies from apple....


Riccbhard, You don't experience the problem ?
Do you use DVI?
In which resolution ?

thxs for your help.
 
I use the DVI-VGA adapter, so I can't speak directly to your problem. However, I have noticed that either the adapter or the plug on my Mac Mini is so flakey that I have to jiggle the cable every time I move the Mac in order to get a working signal to the monitor. Often, if I don't, the power indicator on the monitor (a Sony CPD monitor) cycles through green and orange, indicating a singal error.

If something you do with your mouse causes glitches onscreen it can mean two things to my mind. First, too much signal noise is getting between the Mac and the monitor. Since it is the mouse, try moving the mouse cable as far away from the DVI cable as you can. Try using a different mouse, if you have one. Try using a different DVI cable, if you have one (like you are going to have two of those!!) I don't know enough about DVI cables, but if it has only one shielding collar you might try reversing the cable. You can probably reduce the traffic on the cable by bumping down the resolution or the color.

The second possibility is, of course, a hardware failure.

If you can rule out the first problem by isolating the Mac from every possible source of EM noise (as much as you can), you should be able to take your problem back to Apple.

(after checking a few pages.... I've noticed a lot of video cables out there that are about as thick as an ethernet cable. If you are using one of those, I would doubt strongly that it is well shielded. A good video cable should have some weight to it, suggesting plenty of shielding).
 
In fact I think Glicthes occur when there is CPU activity: moving the mouse over the dock create the zoom effect on the items of the dock, and this must be CPU consuming (be it the CPU or the video chip...). It also occurs when displaying a video for instance, without moving the mouse. ANyway I like you thought of some interferences beetween cables and tried already different ways of putting cables, to avoid anything to get beetween the mac mini and the display along the DVI cable, but it has no effect so far...


I don't have another cable but I could try to orow one...
The problem seems less annoying when i get down to 1280 resolution.
But reducing color numbers seems to have no effect.

My cable seems a good strong one... (again no troubles running at 1600 from an old ATI card on my PC)

I'll try to contact Apple France to check what they say about it.

thxs for your help
 
olivier.marian said:
The problem seems less annoying when i get down to 1280 resolution. But reducing color numbers seems to have no effect.
Click to expand...
Good luck. It does sound like bus noise is interfering with the monitor signal. I don't know enough about DVI, but I guess it is a kind of component video interface (it certainly has enough pins to be one), so I shouldn't have thought reducing the color depth would have had an effect. Sorry about that.
 
I just hooked up a Geffen 2x1 DVI KVM switch to my pc and mac mini. The mac mini was working perfectly before but now I get the same problem reported above except my horizontal flickering lines are usually green. It does seem to intensify with CPU usage as well.

Since this just started happening since I hooked up my KVM switch about 15 minutes ago, I think it does have something to do with interference or the cables not being seated properly... I'm going to fiddle some more and I'll post my findings when I know a bit more.
 
If trying another monitor somewhere doesnt help, it may be a problem with the Mac itself. Monitors I believe have three color spectrums. Red, Green, and Blue. If it is indeed a problem with the Mac, send it back to Apple. You said it cannot be connected to the other monitor because it's not DVI? Chances are it's VGA. Use the DVI-VGA adapter that comes with the Mac.
 
Hmm. It displays fine on any VGA monitor I connect mine to. Couldnt you just adjust the brightness and/or contrast on the monitor?. Maybe find another cheap DVI monitor on eBay?
 
Hi again Riccbhard,

Sure I can probably buy anothe monitor, but this is not what i want to do...
I have of course tried to setup brightness... If you take the time to go through the links I provided you will see that this is a real problem not just something i miss on setting up my monitor... ;-)

10.4.1 did not fix the thing for me...

I will look at this as some people seem to have fixed their DVI problem with it (not the DVI2GVA rpoblem.)

http://www.3dexpress.de/displayconfigx/#Usage
 
Hello,
I found a solution for 1280 1024 resolution.

go to http://www.pyehouse.com/lynn/cscreen.php
download cscreen and run cscreen -d 32 -x 1280 -y 1024 -r 57
This adds a 1280 1024 @ 57Hz resolution.
This solves the DVI fuzzy lines problem, no more lines or dots appearing, nice DVD playing....

This is ***freeware***, and much more convenient to use than SwitchResX...


Instructions...
1. Download the cscreen application
2. Mount the cscreen disk image by double-clicking on the "cscreen.dmg" file that you just downloaded
3. Open the Terminal (located in Applications/Utilities) and enter the following command:
sudo cp /Volumes/cscreen/cscreen /usr/local/bin/
then hit return (you will be prompted for the administrators password)
****
If you get the message "directory /usr/local/bin does not exist" enter the following commands:
sudo mkdir /usr/local/bin/
then...
sudo cp /Volumes/cscreen/cscreen /usr/local/bin/
****

4. If you are comfortable using the Script Editor, you can easily create a script.
Here's the single line of AppleScript code....

do shell script "/usr/local/bin/cscreen -d 32 -x 1280 -y 1024 -r 57"

5. Open the System Preferences and choose "Accounts"
6. Select the "Startup Items" tab and then hit the "+" button
7. Locate and highlight the AppleScript you just made, then hit the "Add" button.
8. Quit out of System Preferences

Everything should be installed now. The next time you reboot your computer the AppleScript will run, and your monitor will be automatically set!


This worked for me, I made several things i think this is how I made it looking at indications on several forums. I'm new with scripts so correct me if I made a mistake in my indications.

Hope this helps, and if you see a solution for 1600*1200 let me know...
all the best,
olivier
 
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