Replacing The Heat-Sink - Lenovo 300 Maintenance Manual

b. Connect the system fan power cable to the connector on the motherboard.
Step 13. Reattach the EMI cover, rear cover, hinge, foot cover and stand base.

Replacing the heat-sink

Note: Turn off the computer and wait 3 to 5 minutes to let it cool down before removing the cover.
Note: It may be helpful to place the computer face-down on a soft flat surface for this procedure. Lenovo
recommends that you use a blanket, towel, or other soft cloth to protect the computer screen from scratches
or other damage.
To replace the heat-sink:
Step 1. Remove any media (disks, CDs, DVDs, or memory cards) from the drives, shut down the operating
system, and turn off the computer and all attached devices.
Step 2. Unplug all power cords from electrical outlets.
Step 3. Disconnect all cables attached to the computer. This includes power cords, input/output (I/O)
cables, and any other cables that are connected to the computer. Refer to "Left and right view"
and "Rear view" for help with locating the various connectors.
Step 4. Remove the stand base. Refer to "Removing the stand base".
Step 5. Remove the foot cover. Refer to "Removing the foot cover".
Step 6. Remove the hinge. Refer to "Removing the hinge".
Step 7. Remove the rear cover. Refer to "Removing the rear cover".
Step 8. Remove the EMI cover. Refer to "Removing the EMI cover".
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Lenovo All-In-One 300 Computer Hardware Maintenance Manual