NEC NP-NC900C-A Service Manual page 74

KEY PART REPLACEMENT (Method of disassembly/Photo taken from life)
1-19 CPU Board & Fan 17 Module
Loosen 3 screws on the CPU board. And, then take the Fan 17 off. Torque: 5~6 kgf-cm.
Loosen 2 screws on the Fan 17 module to take Fan 17 off. Torque: 5~6 kgf-cm.
Loosen 1 screw on the control module. And, then release 3 pin hooks to take shield cover off.
Torque: 5~6 kgf-cm.
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5-23