IBM 6866 Personal Computer User Manual


 
Undetermined problem
Check the power supply voltages. See “Power supply” on
page 129. If the voltages are correct, return here and
continue with the following steps.
1. Power-off the computer.
2. Remove or disconnect the following, if installed, one
at a time:
a. Non-IBM devices
b. External devices (modem, printer, or mouse)
c. Any adapters
d. Hard disk drive
e. Diskette drive
f. Memory modules
Before removing or replacing memory modules,
see “System board memory” on page 157.
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 146.
206 IBM PC 300/IntelliStation Vol 3 HMM