Remove the four screws at the rear of the chassis that secure the power supply.
Remove the power supply retaining screws located inside the computer chassis.
Slide the power-supply assembly toward the front of the computer, remove it from the chassis.
Install the new power-supply assembly into the chassis so that the screw holes in the power-supply assembly align with those in the chassis. Note: Use only the screws provided by Lenovo.
Install and tighten the four screws at the rear of the chassis to secure the power-supply assembly.
Install and tighten the 2 screws that secure the power supply to the inside of the chassis.
Check the power supply and ensure it is the correct replacement. Some power supplies auto sense the voltage, some power supplies are voltage specific, and some power supplies have a voltage selection switch. Use a ballpoint pen to slide the switch, if necessary.
Note: For models that have a switch:
If the voltage supply range is 100-127 V ac, set the switch to 115 V.
If the voltage supply range is 200-240 V ac, set the switch to 230 V.
Replace the heat sink.
Note: You can reuse the heat sink without replacing the grease as long as the grease on the heat sink or the microprocessor has not been disturbed or contaminated. Be careful not to touch the heat sink or set the heat sink down where the grease comes in contact with any surface or contaminates.
Reconnect the heat sink fan cable.
Reconnect all the power supply cables to the drives and the system board.