Lenovo ThinkCentre M90t Gen 3, Hardware Maintenance Manual, Page: 98 / 104

• Ensure that a new VRM heat sink is installed when you install the system board. If the new system board
does not come with a VRM heat sink, see “VRM heat sink” on page 92 to install one first.
• The failing system board must be returned with a microprocessor socket cover to protect the pins during
shipping and handling.
Microprocessor socket cover installation procedure
1. After you have removed the microprocessor from the failing system board, close the microprocessor
retainer. Then, put the lever to the locked position to secure the retainer in place.
2. Note the orientation of the socket cover, and install one side of the socket cover into the microprocessor
socket. Carefully press the other side of the socket cover downward until the socket cover snaps into
position.
Note: The microprocessor socket cover might look slightly different from the illustration.
3. Carefully check the four corners of the socket cover to ensure that the cover is seated securely.
4. Follow any additional instructions that are included with the replacement part you received.
VRM heat sink
Prerequisite
Before you start, read Generic Safety and Compliance Notices , and print the following instructions.
The heat sink and microprocessor might be very hot. Before you open the computer cover, turn off the
computer and wait several minutes until the computer is cool.
For access, do the following:
1. Remove these parts in order, if any:
• “Computer cover” on page 49
• “Optical drive” on page 50
• “Front bezel” on page 51
• “Primary hard disk drives” on page 52
• “M.2 solid-state drive and heat sink” on page 58
• “Optical drive cage” on page 55
• “Secondary hard disk drives” on page 56
• “PCI-Express connector cable” on page 61
• “PCI-Express card” on page 61
• “Graphics card fan” on page 62
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M90t Gen 3 Hardware Maintenance Manual