Compaq 247320-003 - Deskpro 4000 - 5166 Model 2500/CDS Reference Manual page 211

Message Beeps*
1793-Secondary None
Controller or Disk
Failure
1800-Temperature None
Alert
Invalid Electronic None
Serial Number
Audible 2S
Audible 1L, 3S
* L = Long, S = Short
Probable Cause
Hard drive circuitry error.
Internal temperature exceeds
specification.
Electronic serial number has
become corrupted.
Power-on successful.
FailSafe Boot Block ROM
detects invalid system ROM.
Recommended Action
Run the Configuration and
Diagnostics utilities.
Check that computer air vents are
not blocked and cooling fan is
running.
Run Computer Setup.
None.
Refer to recovery procedure in
"FailSafe Boot Block ROM" section
of Chapter 2, "Understanding and
Using Intelligent Manageability."