As reported by Integrated Micro Solutions, the Twin Turbo 128M card is not compatible with the Mac Portrait 1700 Pivot Display.
The workaround is to pull the "Twin Turbo Accelerator 2.0" file from the Extensions folder. This will allow the monitor to work in landscape (horizontal) mode only. All pivot functions will be disabled.
The Twin Turbo 128M Card ships standard on PowerTower Pros, and can be purchased separately for any PCI-based system.
For more information, contact IMS Technical Support at (408) 369-8282.
Machines Affected: PowerBase, PowerCenter, PowerCurve, PowerTower, PowerTower Pro, PowerWave