IBM Aptiva Hardware Handbook page 118

To reset the jumper, do the following:
1.
Locate the jumper you need to reset.
108 Installing an upgrade processor
JP38
2.
Lift the jumper from Position 1, move it to
Position 2. See the example.
Position 1
Jumper
Jumper
Pins
3.
Reinstall all hardware you removed to access the
processor socket.
Position 2