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Maintenance and Troubleshooting 4-5
TROUBLESHOOTING
This subsection provides information that helps isolate and repair computer malfunctions at the
field level. Step-by-step instructions for diagnosing and solving computer hardware problems are
provided.
If disassembly is required, see Sections 5 and 6. Connector pin assignments are given in Appen-
dix A. Jumper settings are explained in Section 2.
Error Messages
Messages may appear when running NEC utilities. Table Section 4-2 describes possible system
error and warning messages and their meanings. Table Section 4-3 describes possible ISA NMI
error messages.
Table Section 4-2 System Error Messages
Message
Description
8042 Gate – A20 error
Gate A20 on the keyboard controller (8042) is not working.
Replace the 8042.
Address Line Short
Error in the address decoding circuitry on the system board.
C: Drive Error
Hard disk drive C does not respond. Run Setup to correct this
problem. Also, check the C hard disk drive type in Setup to
make sure the hard disk drive type is correct.
C: Drive Failure
Hard disk drive C does not respond. Replace the hard disk drive.
Cache Memory Bad, Do Not
Enable Cache
Cache memory is defective.
CH-2 Timer Error
Most AT systems include two timers. There is an error in
Timer 2.
CMOS Battery State Low
CMOS RAM is powered by a battery. The battery power is low.
Replace the RTC on the system board.
CMOS Checksum Failure
After CMOS RAM values are saved, a checksum value is
generated for error checking. The previous value is different from
the current value. Run Setup.
CMOS System Options Not
Set
The values stored in CMOS RAM does not match the type
detected by the BIOS. Run Setup.
CMOS Display Type Mismatch
The graphics type in CMOS RAM does not match the type
detected by the BIOS. Run Setup.
CMOS Memory Size Mismatch The amount of memory on the system board is different than the
amount in CMOS RAM. Run Setup.
CMOS time and date not set
Run Setup to set the date and time in CMOS RAM.
Summary of Contents for PowerMate VP75
Page 147: ...Desktop Repair 5 21 ...
Page 173: ...Minitower Repair 6 25 ...