To gain better access to the power supply, push the two tabs securing the floppy drive out and slide the floppy drive forward a few inches.
If you have a CD-ROM drive installed in the Mac, disconnect the SCSI ribbon cable, the CD-ROM power supply cable, and the CD-ROM audio cable. Remove the EMI shield in the front of the CD-ROM drive also.
Push the power supply toward the front of the computer, lift up the side of the power supply closest to the floppy drive, and take the power supply out of the Mac.
Remove the floppy drive cable from the motherboard. It may be necessary to lift up the edge of the motherboard to make it easier to remove the connector.
Remove the speaker cable from the motherboard.
Remove the LED cable from the motherboard.
Make sure to pull only on the connector, and not the wires, or you will risk damage to the connection.
If you have a CD-ROM drive installed in the Mac, remove the CD-ROM audio cable from the motherboard.
The chassis is secured to the bottom cover by two tabs at the front of the unit, two rail and tab sets at the sides of the unit, support posts at the back of the chassis, and hidden brackets that slide into the bottom cover.
Step 1: Press up on one of the front tabs while lifting the support post. Step 2: Repeat this step on the other side until the internal chassis slides easily toward the back of the computer.
