NEC NP-NC900C-A Service Manual page 77

KEY PART REPLACEMENT (Method of disassembly/Photo taken from life)
1-22 Security Switch & Mother Board
Loosen 1 screw on control module. Then, take off the security switch from control module.
Torque: 1.5~2 kgf-cm
Loosen 16 screws on mother board. Then, take off the mother board from control module.
And, then unplug 1 pc connector from mother board. Torque: 5~6 kgf-cm
Then, take off mother board.
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5-26