Tektronix Phaser 300X - Manual (Page 137)

6 Troubleshooting
6-28 Phaser 300X Color Printer
The startup page prints although you disabled it. The printer’s power-up
self-test can detect problems that do not necessarily make the printer
completely inoperable. Examples of these non-fatal errors include faulty
printer ports and some memory failures.
If the printer detects a non-fatal error at power-up, the startup page prints,
even if you have disabled it.