17'' Apple Studio Display(LCD;ADC) Resolution Problem

17" LCD Apple Display is definitely 1280 x 1024 rez.

Did you zapp PRAM? (startup with < COMMAND > , < OPTION > , < P > , < R > pressed during boot, until you hear startup chime 3 times.

Otherwise startup with < COMMAND > , < OPTION > , < O > , < F > , which brings you the OpenFirmware screen.
Type: "reset-nvram"
then, type: "reset-all" (all without quotation marks) ... The Mac will reboot instantly.

The idea of this all is to force your Mac to re-recognize the attached screen.
Hope it works.

BTW I assume a "normal" grfx card is installed? i.e. Ati Radeon 9000, 9700 or 9800 (probably not this one... no ADC) or nVidia GeForce 4?

 

When resetting the VRAM doesn't work, Apple suggests:

Drag the com.apple.windowserver.plist preference file (located in /Library/Preferences) to the Trash.
When you connect a compatible PowerBook computer to a compatible display using the DVI to ADC adapter, resolutions other than the native display resolution do not scale.
Some bundled display cards will not work with all ADC features when an display is connected using the Apple ADC to DVI Display Adapter. Some examples of features that may not work with bundled display cards include:
Starting up the computer by pressing the display's power button when the computer is off.
Putting the computer to sleep by pressing the display's power button when the computer is on.
Shutting down the computer by pressing the display's power button when the computer is in Open Firmware mode.