IBM 6648 - Manual (Page 104)

Message/Symptom FRU/Action
Serial or parallel port device failure (system board
port)
1. External Device Self-Test OK?
2. External Device
3. Cable
4. System Board
Serial or parallel port device failure (adapter port)
1. External Device Self-Test OK?
2. External Device
3. Cable
4. Alternate Adapter
5. System Board
Some or all keys on the keyboard do not work
1. Keyboard
2. Keyboard Cable
3. System Board
Undetermined problems
Check the power supply voltages. See “Power supply” on page 30. If the
voltages are correct, return here and continue with the following steps.
1.
Power-off the computer.
2. Remove or disconnect the following components (if installed) one at a
time.
a.
Non-IBM devices
b. External devices (modem, printer, or mouse)
c. Any adapters
d. Riser card
e. Memory modules
Before removing or replacing memory modules, see “System board
memory” on page 55.
f. Extended video memory
g. External Cache
h. External Cache RAM
i. Hard disk drive
j. Diskette drive
3. Power-on the computer to re-test the system.
4. Repeat steps 1 through 3 until you find the failing device or adapter.
If all devices and adapters have been removed, and the problem continues,
replace the system board. See “Replacing a system board” on page 45.
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Hardware Maintenance Manual: IBM NetVista Computer Types 6058, 6059, 6269, 6568, 6569, 6578, 6579, 6648,
6649