4-12 Maintenance and Troubleshooting
Beep Codes
One beep indicates that the system has completed its power-on self-test. If a long beep or a
series of long beeps occur, power off the computer and try again. If the long beeps persists,
see Table Section 4-8 for the diagnostic beep codes.
The beep codes are announced on the speaker only if a fatal failure is detected. For instance,
three long beeps indicates a failure in the first 64 K of RAM.
Table Section 4-8 Diagnostic Beep Codes
Message
Beeps
Description of Failure
Refresh Failure
1
The memory refresh circuit on the system board is
faulty.
Base 64 KB Memory Failure
3
Memory failure in the first 64 KB.
Timer Not Operational
4
Memory failure in the 64 KB of memory or timer 1
on the system board is not functioning.
Processor Error
5
The CPU on the system board generated an error.
8042 – Gate A20 Failure
6
The keyboard controller (8042) may be bad. The
BIOS cannot switch to protect mode.
Processor Exception Interrupt
Error
7
The CPU generated an exception interrupt.
Display Memory Read/Write
Error
8
The system’s video adapter is either missing or its
memory is faulty. This is not a fatal error.
ROM Checksum Error
9
ROM checksum value does not match the value
encoded in the BIOS.
CMOS Shutdown Register
Read/Write Error
10
The shutdown register for CMOS RAM failed.
Cache Error
11
The cache is faulty.
CMOS Battery Replacement
Remove the 3-volt lithium battery from system board as follows.
1.
Turn off and unplug the system unit and any external option connected to it.
2.
Remove the system unit cover.
