IBM RT PC 10 Hardware Maintenance And Service page 151

Step 3
3-106 Service Manual
One of the remaining boards or adapters is failing.
1. Set the power switch on the system unit to Off.
2. Exchange the remaining boards and adapters one at a time in the
following order; the processor board, the system board, the fixed-disk
and diskette drive adapter, the display adapter, then the memory board
in slot C.
3. Be sure the power has been off 30 seconds, then set the power switch
on the system unit to On.
4. Try the failing procedure.
DID YOU FIND THE PROBLEM?
NO Try a new set of diagnostic diskettes.
If
the problem still occurs,
contact your service support person.
YES Go to "Step 5" on page 3-108.