Beep Codes and Error Messages
3-3
3-2-4
Keyboard-controller test
failure
Faulty keyboard controller
(defective system board)
3-3-4
3-4-1
3-4-2
Screen initialization failure
Screen-retrace test failure
Search for video ROM failure
Faulty video subsystem
(defective system board)
4-2-1
4-2-2
4-2-3
4-2-4
No timer tick
Shutdown failure
Gate A20 failure
Unexpected interrupt in
protected mode
Defective system board
4-3-1
Memory failure above
address 0FFFFh
Faulty or improperly seated
DIMM
4-3-3
Timer-chip counter 2 failure
Defective system board
4-3-4
Time-of-day clock stopped
Bad battery or defective
system board
4-4-1
4-4-2
Serial-port test failure
Parallel-port test failure
Faulty I/O chip (defective
system board)
4-4-3
Math coprocessor failure
Faulty microprocessor chip or
system board
4-4-4
Cache test failure
Defective microprocessor or
system board
Table 3-1. POST Beep Codes (continued)
Beep Code
Error
Probable Causes
