HP TC4400 - Manual (Page 123)

5–40 Maintenance and Service Guide
Removal and Replacement Procedures
5.16 Button Board
1. Prepare the computer for disassembly ( Section 5.3 )
and remove the following components:
a. Keyboard cover ( Section 5.8 )
b. Keyboard ( Section 5.9 )
c. Display assembly ( Section 5.15 )
Button Board Spare Part Number Information
Button board (includes button board cable) 419112-001