Troubleshooting; Diagnosing And Solving Problems; Problems And Solutions - NEC POWERMATE V Service Manual

4-4 Maintenance and Troubleshooting

TROUBLESHOOTING

This subsection provides information that helps isolate and repair system malfunctions at the
field level. Step-by-step instructions for diagnosing and solving system hardware problems
are provided.
If disassembly is required, see Section 5. Connector pin assignments are given in
Appendix A. Jumper settings are given in Appendix B.

Diagnosing and Solving Problems

One beep indicates that the system has completed its POST test. If intermittent beeping
occurs, power off the system and try again. If the beeping persists, see Table 4-2. The table
summarizes problems that may develop during system operation and lists (in sequential
order) suggested corrective actions.
Problem
No power
Power supply
malfunction
Table 4-2 Problems and Solutions
Symptom
Power lamp on computer
status panel will not light.
Any one or more of the
following conditions could
occur:
Front panel lamps out,
diskette and/or hard drives do
not spin, monitor blank,
interface ports not working,
and keyboard lamp out and/or
cannot input from keyboard.
Solution
1. Check that the power cord is plugged
into the AC connector on the computer.
Check that the other end of the cord is
plugged into a live properly grounded AC
power outlet.
2. Check cable connections between
power supply and system board.
3. Systematically eliminate possible
shorted PCBs by removing cables and
expansion boards.
4. Check the +5 and +12 power supply
voltages (see Appendix A, Connector Pin
Assignments). Measure voltages with the
system board installed.
5. Replace power supply.
6. Replace system board.
1. Perform steps 1 through 4 listed in this
table under No Power.
2. Check power supply voltages. Voltages
should be measured with a load on them
(system board plugged in). See Appendix
A for connector pin assignments and
Section 1 for the power supply
specifications.
3. Replace power supply.