Dell OptiPlex 780 - Manual (Page 23)

Amber Second state of the light at power up. Indicates the POWER_GOOD signal is active and it is probable that
the power supply is fine. Look at the diagnostic lights for further information.
Blinking
Green System is in a low power state, either S1 or S3. Look at the diagnostic lights to determine which state the
system is in.
Solid
Green System is in S0 state, the normal power state of a functioning machine.
The BIOS will turn the light to this state to indicate it has started fetching op-codes.
Beep Codes
If the monitor cannot display error messages during the POST, the computer may emit a series of beeps that identifies the
problem or that can help you identify a faulty component or assembly. The following table lists the beep codes that may
be generated during the POST. Most beep codes indicate a fatal error that prevents the computer from completing the
boot routine until the indicated condition is corrected.
Code Cause
1-1-2 Microprocessor register failure
1-1-3 NVRAM read/write failure
1-1-4 ROM BIOS checksum failure
1-2-1 Programmable interval timer failure
1-2-2 DMA initialization failure
1-2-3 DMA page register read/write failure
1-3 Video Memory Test failure
1-3-1 through 2-4-4 Memory not being properly identified or used
3-1-1
Slave DMA register failure
3-1-2 Master DMA register failure
3-1-3 Master interrupt mask register failure
3-1-4 Slave interrupt mask register failure
3-2-2 Interrupt vector loading failure
3-2-4 Keyboard Controller Test failure
3-3-1 NVRAM power loss
3-3-2 Invalid NVRAM configuration
3-3-4 Video Memory Test failure
3-4-1 Screen initialization failure
3-4-2 Screen retrace failure
3-4-3 Search for video ROM failure
4-2-1 No timer tick
4-2-2 Shutdown failure
4-2-3 Gate A20 failure
4-2-4 Unexpected interrupt in protected mode
4-3-1 Memory failure above address 0FFFFh
4-3-3 Timer-chip counter 2 failure
4-3-4 Time-of-day clock stopped
4-4-1 Serial or parallel port test failure