IBM RT PC 10 Hardware Maintenance And Service page 118

Step 6
1. Set the power switch on the system unit to Off.
2. Disconnect the power connector at the cooling fan.
3. Be sure the power has been off 30 seconds, then set the power switch
on the system unit to On.
4. Wait 15 seconds, then answer the following question.
bJD
IS THE POWER-ON INDICATOR ON?
YES Exchange the cooling fan assembly, then connect any connectors
that are disconnected. This completes the repair.
NO
Continue on the next page.
Problem Isolation Charts 3-73