NEC Versa 550 Series Service Manual page 102

5-6 Troubleshooting and Repair
Message
Keyboard clock line failure
Keyboard data line failure
Keyboard stuck key failure
Memory failure at hex-
value, read hex-value,
expecting hex-value
Unexpected interrupt in
protected mode
Real time clock failure
Table 5-2 POST Error Messages
Possible Cause
The keyboard, the
keyboard cable
connection, or the
keyboard controller is
defective.
The keyboard controller
firmware has failed.
A key is jammed.
Circuitry associated with
the memory chips has
failed.
Hardware interrupt or NMI
occurred while in
protected mode.
The RTC or battery failed.
Action
Make sure the keyboard
cable and keyboard are
connected properly. Check
the keyboard controller and
the system board. Turn the
power off, then back on
again. If the problem persists,
contact qualified service
personnel.
Check the keyboard
controller and system board.
Turn the power off, then back
on again. If the problem
persists, contact qualified
service personnel.
Locate the jammed key and
fix it. Make sure the keyboard
cable and keyboard are
connected properly. Turn the
power off, then back on
again. If the problem persists,
contact qualified service
personnel.
Turn the power off, then back
on again. If the problem
persists, contact qualified
service personnel.
Check the timer chip or the
interrupt controller on the
system board.
Run SETUP and turn the
power off and on. If the
problem persists, replace the
RTC battery. If the problem
remains, contact qualified
service personnel.