Looking from the back, pull up the board, releasing from the pins of the main board.
Finally you can remove the power switch.
And this is the power source board.
When working on the power supply, be very careful not to touch the capacitor leads or any exposed solder joints on the back of the power supply. Only handle the board by the edges.
And now is the time to remove the fan wire from the main board, using a precision tweezer. But.. I can't, it is simply stuck. I already removed this ealier, but now is harder, so I will try later, in the end of the teardown.
From top, from the left: Ethernet adapter, Ps2 case, Hdd, Cooler, Cooler grid, bottom metal cover protection, screws protectors, screws, Controller board, Power swtich, Power source board, Plastic cover to isolate the power source board, top metal cover, DVD Drive, Expansion Bay cover, main board, reset/eject structure.
Yep in reverse, take your time or you'll be like me breaking things and having to rig it haha. Put the shielding back together, drive, power board, the other shield for hard drive. Everything, plug all connections. Even power-reset buttons. Then put it on the bottom casing, connect controller ports and close it up with top casing.
I put a lot of layers of tape on mine, the last owner of my system was very naughty and disassembled the system when it was still under warranty, so the cable was brokem