Lenovo 4157 - ThinkStation S20 - 2 GB RAM, Hardware Maintenance Manual

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7. Reverse this procedure to install the card.
8. Go to “Completing the FRU replacement” on page 106.
Replacing the heat sink
CAUTION:
The heat sink and microprocessor might be very hot. Turn off the computer and wait
three to five minutes to let the computer cool before opening the computer cover.
Attention
Do not open your computer or attempt any repair before reading and understanding the “Important safety information”
in the
ThinkStation Safety and Warranty Guide that came with your computer. To obtain a copy of the ThinkStation
Safety and Warranty Guide , go to:
http://www.lenovo.com/support.
This section provides instructions on how to replace and install the heat sink.
To replace the heat sink:
1. Open the computer cover. See “Removing the cover” on page 76.
2. Lay the computer on its side for easier access to the heat sink.
3. Remove the heat sink and fan assembly cables from the system board. Note the cable location. See
“Locating parts on the system board ” on page 111.
4. Follow this sequence to remove the heat sink from the system board:
a. Partially remove screw 1 , then fully remove screw 2 , and fully remove screw 1 .
b. Partially remove screw 3 , then fully remove screw 4 , and fully remove screw 3 .
5. Carefully lift the heat sink off of the system board.
6. Remove the plastic cover from the bottom of the new heat sink to expose the heat sink grease (this cover
protects the heat sink grease from contamination).
Chapter 11
.
Replacing FRUs (Type 4155, 4158, 4218)
119