Dell OptiPlex 990 (Early 2011) - Manual (Page 5)

16 Power Supply..........................................................................................49
Removing The Power Supply ..........................................................................................49
Installing The Power Supply ...........................................................................................51
17 System Board..........................................................................................53
Removing The System Board ..........................................................................................53
Installing The System Board ...........................................................................................54
18 Power Supply Unit (PSU) Thermal Sensor.........................................57
Removing The PSU Thermal Sensor ...............................................................................57
Installing The PSU Thermal Sensor ................................................................................58
19 System Setup..........................................................................................59
System Setup ..................................................................................................................59
Boot Menu .......................................................................................................................59
Boot Menu Enhancements ..............................................................................................59
Timing Key Sequences ....................................................................................................60
Beep Codes and Text Error Messages ............................................................................61
Navigation .......................................................................................................................61
System Setup Options .....................................................................................................61
20 Troubleshooting......................................................................................73
Diagnostic LEDs ..............................................................................................................73
Diagnostic Light Patterns ..........................................................................................73
Beep Codes .....................................................................................................................80
Error Messages ...............................................................................................................83
Address mark not found ............................................................................................83
Alert! Previous attempts at booting this system have failed at checkpoint
[nnnn]. For help in resolving this problem, please note this checkpoint and
contact Dell Technical Support.
...............................................................................83
Alert! Security override Jumper is installed. ............................................................84
Attachment failed to respond ...................................................................................84
Bad command or file name ......................................................................................84
Bad error-correction code (ECC) on disk read .........................................................84