Power Computing provided the information in this article and it was deemed accurate as of 14 November 1997. Apple Computer, Inc. is not responsible for its content. This article is being provided as is and will not be updated in the future.

Installation instructions for new SCSI drives for desktop, MT tower, NT tower, ATX tower cases.

To install the new SCSI drive, you will need a small coin or a straight-edge screwdriver and a Phillips screwdriver.

Preparing the Drive

First, we'll need to set the ID number and termination on the drive. The drives are SCSI devices and they need a unique ID number. If you have external devices, you may need to change their ID numbers to accommodate the new drive. The chart below shows you the normal settings for SCSI devices installed in your computer.

Device Typical ID
Hard Drive 0
Jaz Drive (optional) 2
CD-ROM 3
Zip Drive (optional) 5
Logic Board 7

Check the documentation that came with your drive to determine how to set the ID and termination. You will need to set the termination for OFF unless you are replacing the drive that's at the end of the SCSI ribbon. The recommended ID number for a second hard drive is ID 1 and the recommended ID for a new CD drive is 3, but you can set it for any available number.

Drive Rails for Tower Units with one thumbscrew securing the case or Desktop Units
If you are installing a 5.25 drive into a 5.25 bay, you will need to attach small plastic rails.

If you are installing a 3.5 drive into a 5.25 bay, you will need to attach the U-shaped metal brackets to the drive first, then attach the plastic rails.

Tower Units with 4 thumbscrews securing the case do not need drive rails.

Drive Rail for TowerPro Units
If you are installing a 5.25 drive into a 5.25 bay, you will need to attach a small metal rail to the right side of the drive.

If you are installing a 3.5 drive into a 5.25 bay, you will need to attach the U-shaped metal brackets to the drive first, then attach the metal rail to the right side.

If you are installing a 3.5 drive into the floppy cage or RAID cage, you need to remove the cage and install the drive. No rails are needed.


Remove the case per PowerSource 1724

When attaching cables, be certain to use a middle connector on the grey SCSI ribbon. the end connector needs to stay on the drive it is currently attached to. It may be easier to attach the other cables if you remove the end connector temporarily. All the cables are keyed, so they cannot be attached upside-down. Except where noted, drives are to be installed label side up with the connectors facing the back of the computer.

Desktop and Tower Units with one screw securing the case

A hard drive will go into the bay that sits on top of the power supply. That bay is held in place by a single screw on the back of the case. Remove that screw. Detach any cables going to the drive in that bay. Lift the left edge of that bay toward the right side of the computer. The drive will be installed label down with the power and SCSI connectors furthest from the hinge. Once the drive is screwed into place, put the drive bay back into it's original position and screw it down. Attach both the grey ribbon (SCSI cable) and multicolored cable (power cable) to the two drives. Be certain the end connector on the SCSI drive goes to the same drive it came off of.

If you're installing a CD-ROM drive, it will go into a bay below the floppy drive. If there is a metal plate covering the bottom bay, remove the screws and throw away the metal bracket. With the bracket removed slide the drive into the bay.

When connecting cables it may be easier to attach them with the drive recessed slightly. This drive requires that you plug in three cables. The wide gray SCSI cable, the small audio cable, and the multi-colored power cable.

The wide gray cable will attach to the fifty pin connector, this cable should attach so that the raised ridge in the center of the SCSI connector is facing towards the top of the machine. Make sure that the cable slides all the way down on the connector, and that you are using the connector that is located below the one that connects your CD-ROM.

The next cable is the power cable. This cable is slotted so it will go in only one way.
There is a third cable for audio CD. It's typically a small round grey wire with a 3 or 4 prong connector on the ends. One end attaches to the CD-ROM drive. The other end goes on the I/O card (the card to which all the cables go). On the leading edge of the I/O card there two 4 prong connectors. The topmost connector is the audio cable connector. The closed side of the connector faces the back of the computer. If you attach it backwards, it will still work, but your left and right channels will be reversed. If your channels are backwards, just flip the connector the other way. The CD-ROM will function without it, but you won't hear CD audio or Red Book audio.


Tower Units, 4 thumbscrews securing the case

The hard drive will be installed in the bay located either above the floppy drive, or above the CD-ROM drive.

Slide the drive into the bay. It may be easier to connect cables if the drive is not completely pushed into position. You then need to connect the wide gray cable (SCSI cable), and the multi-colored cable (power cable). The power cable is slotted so it will not go in the wrong direction. Once this cable is connected then connect the SCSI cable. The SCSI cable is not slotted so make sure that the notches on the cable are pointed towards the top of the machine.

TowerPro Units

The hard drive will be installed below the CD-ROM Drive. You may need to remove a metal plate if it is blocking the drive bay. To remove the metal plate, insert a Phillips screwdriver into one of the cross shaped holes a pry it loose. Once it's loose, discard it. Slide the hard drive into the bay. Screw in the left side, then secure the rail secured to the right side by screwing it into the front.

3.5 inch drives can be installed into the floppy cage. They go label side up with the connectors toward the rear of the machine.

Drives installed into the RAID rack will be installed label side up, with the connectors facing the front of the computer.

It may be easier to connect cables if the drive is not completely pushed into position. You then need to connect the wide gray cable (SCSI cable), and the multi-colored cable (power cable). The power cable is slotted so it will not go in the wrong direction. Once this cable is connect then connect the SCSI cable. The SCSI cable is not slotted so make sure that the notches on the cable are pointed towards the top of the machine. Once both cables are connected you are ready to test your machine.

Reassemble the computer per PowerSource 1725.

Making sure the drive works.

Before you put the machine back together let's make sure the drive is working and install the software. This part of the installation instructions will work for all machines.

Restart your machine.

Boot from the PowerCD. Go to the Utilities folder on your CD and open the Hard Disk Tool Kit folder. HDT Primer is located in the folder, when this software launches it should scan the SCSI bus, and the hard drive will appear on the line corresponding to the ID number for the drive.

You will need to format the disk. To do that, highlight the line the drive is on and click the Format button in the top right corner of HDT primer. Click OK for all the warnings that the drive will be erased. Once it finishes, install whatever software you want on that drive.

Machines Affected: All desktop, tower and ATX systems