This problem occurs between the time the Quadra identifies a volume as bootable, and when it finds a legitimate system folder - which in a clean install scenario, doesn't exist. The solution for this problem would require a hardware fix, and these particular machines, with the exception of the Quadra 950, are out of production. It is a very rare problem that most people will never encounter.
We recommend that while doing a clean install with one of the above mentioned configurations, that you insert the Install 1 disk before powering up the Quadra. Do not wait for the blinking question mark as with a normal clean install.
This issue does not occur if the Quadra is attached to an Apple 12" Monochrome, 12" RGB, 13" RGB, or 14" RGB. It has not been tested with the Apple 15" portrait, 21" Monochrome or the 17" or 20" Multi-Scan monitors.
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