Power Macintosh G3 (Blue and White): Ghost Monitor When Using PCI Video Cards

A PCI video capture card that works with some PCI-based computers may not work with the Power Macintosh G3 (Blue and White) computer. In those cases, a blank desktop appears after the Power Macintosh G3 (Blue and White) starts up.
The PCI and video architectures are such that the computer thinks a monitor is connected to any PCI card, except for the ATI RAGE 128 card in the 32 bit, 66 MHz PCI slot. This is normally not an issue since you would plan to use a video card you installed. However, some video capture cards also provide VRAM and a connector for external monitors. If you are using the card for capture but are not connecting a monitor to it, the computer still thinks that there is a monitor connected to that card.

The computer initially numbers the external monitors starting from the top-most PCI slot and ending with the 32-bit, 66-MHz PCI slot. Because of this, if you have a monitor connected to the ATI RAGE 128 card but not to the PCI video card, the computer starts up to a blank desktop. This is because the primary monitor with the menu bar is assumed to be connected to the PCI video card. To solve this issue, follow these steps:

  1. Shut down the computer and connect the monitor to the PCI video card.

  2. Connect the VGA adapter that comes with your computer to the ATI RAGE 128 card. This tricks the computer into thinking there is a monitor connected to the card.

  3. Start up the computer. You should now see the menu bar and hard disk.

  4. Open the Monitors & Sound control panel. Check the "Identify the startup screen" box. Drag the Happy Mac icon from the first monitor icon to the second. Then drag the menu bar from the first monitor icon to the second. At this point the menu bar moves to the invisible monitor.

  5. Close the Monitors & Sound window.

  6. Press the power button on the keyboard. The computer beeps and the shutdown/restart dialog appears, but you won't be able to see it because it's on the invisible monitor. Press the Return key and the computer shuts down.

  7. Remove the VGA adapter and connect the monitor to the ATI RAGE 128 card.

  8. Start up the computer.

  9. Open the Monitors & Sound control panel and arrange the monitors so that only the corners are touching. This keeps you from accidentally moving on to the "ghost" monitor while working.

Since these settings are stored in both NVRAM and the Monitors & Sound preferences, you should not encounter this situation again.

Published Date: Feb 20, 2012