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ADC mysteries

Posted by: Coloruser on 2025-09-19 03:15:48

I am running into issues using Rage 128 AGP ADC cards with my 20" ADC Studio Display LCD. At first, I thought it was the Cube´s VRM or power supply, because after a few seconds with the Mac Boot screen, the LCD goes black - even though it still shows the activity light and I can shut down/sleep using the touch control on the screen. So I used another Rage 128 AGP ADC card and - same issue.

I could duplicate the result on my MDD 1.25 Dual. The display works fine when using a Radeon 9000 AGP (R250) 32mb DVI+ADC, but when using the Rage 128 cards, same symptoms as with my Cube. I did not try the Radeon 9000 in the cube as this does not fit and maybe stress the VRM/PSU too much.

Any idea what is going on here? Does the Rage 128 not support the 20" ADC frequency? Studio Displays unfortunately don't tell you whether they lost signal like a standard TFT.

Posted by: finkmac on 2025-09-19 05:28:24

specs here

System requirements

	The Apple Cinema Display requires Mac OS X v10.2 or later, and one of the following systems:
—	Power Mac G4 with an NVIDIA GeForce2 MX, GeForce3, GeForce4 MX, or GeForce4 Titanium graphics card or ATI Radeon 7500, 9000 Pro, or 9700 Pro graphics card
—	PowerBook G4 with a DVI port and an Apple DVI to ADC Adapter
	A second display can be used with a Power Mac G4 via the DVI port on the NVIDIA GeForce4 MX, GeForce4 Titanium, ATI Radeon 7500, Radeon 9000 Pro graphics card and the Apple DVI to ADC Adapter.

Posted by: chriscarruthers on 2025-09-19 05:53:03

Yeah you need a 32 MB card or more to run the 20”. It will display briefly on boot but not work after that.

Posted by: Coloruser on 2025-09-19 09:19:51

I double checked it with a Rage 128 DVI and the ADC/DVI Adapter. The same results as @chriscarruthers mentioned. Tried again with a ALU Cinema Display 20 - startup screen for a brief moment and then black. At the end it shows that the Rage 128 (GL) was limited on the DVI/ADC side as the VGA port does do 1920x1080 at 60hz. I have a Geforce MX4 in one of my Sawtooths - I will give it a try in the Cube if it fits.