Tyan Computer GX21 - Manual (Page 56)

3.9 Replacing the Power Supply
48 Chapter 3: Replacing Pre-Installed Components
4. Remove the 2 screws from the mounting bracket that
secure the power supply to the chassis.
5. Remove the 2 screws from the power supply rear bracket
that secure it to the chassis.
6. Lift the power supply clear of the chassis.
7. Remove the 2 screws that secure the power supply
bracket to the power supply and remove the bracket.