Classic Mac Hardware (Troubleshooting, Upgrading, & Modifying) > Video Cards, Monitors, & Displays

Mac Mini G4 pixel clock limited to 135Mhz

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darthnVader:

--- Quote ---It turns out the G4 Mini has some issue with coherent vs. non-coherent LCD's and that my LCD needs a Pixel Clock of 146.25 MHz for 1680x1050 and the maximum the G4 Mini can do is 135 MHz. See:
http://developer.apple.com/documentation/Hardware/DeveloperNotes/Macintosh_CPUs-G4/MacMiniG4/3Input-Output/chapter_4_section11.html
--- End quote ---

The doc linked seems to be gone, but I assume the info is good.

This explains why some of us are having issues with higher res DVI/HDMI displays.

I'm not sure how this can be fixed.


--- Quote ---With SwitchRes X, you can let it fill in all the blanks according to pre-set formulas. If, when building a custom timing, you click on the "Use simplified settings:" check box and then select "CVT-RB" from the associated pop-up menu, all you need type in is "1920" for Horizontal Active and "1080" for Vertical Active and "60" Hz for Vertical Scan rate. SRX will fill in all the other numbers. The dot clock will come down to 138.5 MHz when you do this. That's not quite the magic figure of 135 MHz, but it's close enough that it will probably work. If not, you can uncheck "Use simplified settings" and then edit the horizontal front porch, sync and back porch to shave off time (do this in 8 pixel increments) until the pixel clock reaches 135 MHz.

Hopefully all the other strangeness you are seeing relates to the pixel clock issue and all the problems will go away once you have a working 1080p timing.
--- End quote ---

DieHard:
Played with the Mini all day today, it is a total beast under OS 9 and is super quiet !  The video at 1280 X 1024 is ROCK solid.  I will be moving it to the home lab and connecting it to a 25" via DVI... I will report back

FdB:
Oh sure. Taunt an old man with yet another quest
and your new-fangled modern gizmos! :o

Does sound rather cool however.

darthnVader:

--- Quote from: Fury deBongo on March 31, 2018, 10:03:31 PM ---Oh sure. Taunt an old man with yet another quest
and your new-fangled modern gizmos! :o

Does sound rather cool however.

--- End quote ---

You young whipper snappers and your Mini's, back in my day we had Apple IIe's, you had to spend all day writing programming for them when you wanted them to do something, and they were the size of a small car.

That's the way it was and we liked it. ;D

macStuff:

--- Quote from: DieHard on March 31, 2018, 09:25:07 PM ---Played with the Mini all day today, it is a total beast under OS 9 and is super quiet !  The video at 1280 X 1024 is ROCK solid.  I will be moving it to the home lab and connecting it to a 25" via DVI... I will report back

--- End quote ---

so whats the benefit of running os9 on a mini?
what connections does it have on the back?
ethernet / dvi / usb2.0 / firewire ?

id like to see someone put up a video on youtube of a mini running os9!
someone should do that and then put a link to this site on it..
thats the kind of video that will end up going viral
think strategically and use it to our advantage to promote


--- Quote ---Display Support:   Single Display   Resolution Support:   1920x1200
Details:   The DVI video output supports digital resolutions up to 1920x1200. Apple also reports that it supports the "20-inch Apple Cinema display and 23-inch Apple Cinema HD display; supports coherent digital displays up to 154MHz; supports non-coherent digital displays up to 135MHz." VGA output (using the provided adapter) supports analog resolutions as high as 1920x1080. S-Video and composite video (to connect to a projector or TV) requires the Apple DVI to Video adapter (sold separately).
--- End quote ---

what does this mean? coherent vs non-coherent?
does this mean darths monitor is incoherent?? :D

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