Lenovo ThinkCentre M90a Pro Gen4 Hardware Maintenance Manual page 77

To dispose of the coin-cell battery, refer to the "Lithium coin-cell battery notice" in the Safety and Warranty
Guide.
For access, remove the following parts in order, if any:
• "Computer stand" on page 51.
• "Rear I/O cover" on page 54.
• "System board shield" on page 55.
• "VESA mount bracket" on page 57.
• "Cover presence switch (intrusion switch)" on page 58.
• "Hard disk drive" on page 59.
• "Optical drive" on page 59.
• "M.2 solid-state drive" on page 61.
• "Thunderbolt card" on page 62
• "Memory module" on page 63.
• "Wi-Fi card and Wi-Fi card shield" on page 64.
• "Card reader board" on page 64.
• "GPU card" on page 65.
• "System fan" on page 66.
• "Heat sink" on page 67.
• "Microprocessor" on page 68.
• "System board" on page 69.
Removal steps
Note: A protective film might cover the coin-cell battery. To access the coin-cell battery, remove the
protective film first.
Note: After installing a new coin-cell battery, reset the system date and time in the UEFI BIOS menu.
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Chapter 6 Hardware removal and installation