IBM 8688 manual Check if a CD is in drive, Manually eject media and close drive

Code/Explanation	FRU/Action
0520h (No CD in the drive.)	1.	Check if a CD is in drive.
	2.	Confirm that drive is configured.
	3.	Check drive cables and connections.
	4.	Drive.
	5.	I/O board or SCSI add-on controller.
0521h (CD-ROM read error.)	1.	Confirm that drive is configured.
	2.	Check drive cables and connections.
	3.	Drive.
	4.	I/O board or SCSI add-on controller.
0523h (CD-ROM play error.)	1.	Confirm that drive is configured.
	2.	Check drive cables and connections.
	3.	Drive.
	4.	I/O board or SCSI add-on controller.
0524h (CD Self-test error.)	1.	Confirm that drive is configured.
	2.	Check drive cables and connections.
	3.	Drive.
	4.	I/O board or SCSI add-on controller.
0525h (CD Open error.)	1.	Manually eject media and close drive.
	2.	Retry tray function.
	3.	Confirm that drive is configured.
	4.	Check drive cables and connections.
	5.	Drive.
	6.	I/O board or SCSI add-on controller.
0526h (CD Close error.)	1.	Manually eject media and close drive.
	2.	Retry tray function.
	3.	Confirm that drive is configured.
	4.	Check drive cables and connections.
	5.	Drive.
	6.	I/O board or SCSI add-on controller.
0527h (CD Buffer error.)	1.	Confirm that drive is configured.
	2.	Check drive cables and connections.
	3.	Drive.
	4.	I/O board or SCSI add-on controller.
0528h (Pattern compare failed. Check	1.	Check if AMIDiag CD is present in drive.
pattern did not match.)
	2.	Confirm that drive is configured.
	3.	Check drive cables and connections.
	4.	Drive.
	5.	I/O board or SCSI add-on controller.
0529h (CD-ROM random read error.)	1.	Confirm that drive is configured.
	2.	Check drive cables and connections.
	3.	Drive.
	4.	I/O board or SCSI add-on controller.

166IBM xSeries 450 Type 8688: Hardware Maintenance Manual and Troubleshooting Guide