Lenovo THINKCENTRE 4485 - Manual (Page 79)

Undetermined problems
If you encounter undetermined problems, do the following:
1. Turn off the computer and the power.
2. Remove or disconnect the following components (if installed) one at a time.
a. External devices (modem, printer, or mouse)
b. Any adapter cards
c. Memory modules
d. Extended video memory
e. External Cache
f. External Cache RAM
g. Hard disk drive
h. Diskette drive
3. Turn on the power and the computer to re-test the system.
4. Repeat steps 1 through 3 until you find the failing device or adapter cards.
If all devices and adapter cards
have been removed, and the problem continues, replace the system board. See “Replacing the system
board” on page 100 or “Replacing the system board” on page 150.
Chapter 7 . Symptom-to-FRU index 71