Installing Drives in the External Bays 9-5• If two or more SCSI devices are installed, connectthe devices as follows:— Attach one of the devices to the end connector onthe SCSI cable, and leave the terminator enabledon that device.— Connect the other end of the SCSI cable to thecomputer’s built-in Ultra/Narrow SCSI hostadapter or to an optional SCSI host adapter card.— Disable the terminators on all other devices youattach to the cable.The standard SCSI CD-ROM drive is configured as thelast device on the SCSI cable. Therefore, any additionaldevices attached to the cable should have their termina-tors disabled.See the documentation provided with the SCSI device forinformation on disabling the device’s terminator.SCSI CableThe 50-pin Ultra/Narrow SCSI cable has five connectors:• The connector at the end of the cable farthest awayfrom the other four connectors attaches to the SCSIhost adapter connector labeled “SCSI2 CD-ROM”on the system board.• The other four connectors on the cable attach todevices in the external drive bays.Installing a SCSI DeviceTo install an external SCSI device that uses the built-inUltra/Narrow SCSI controller, follow these steps:1. Prepare the drive for installation.Ground yourself by touching an unpainted metal sur-face on the back of the computer, unpack the drive,and compare the jumper and switch settings withthose in the drive documentation. (See “SCSI Config-uration Information” found earlier in this chapter forinformation on setting the drive’s SCSI ID numberand enabling termination [if required].) Change anysettings necessary for this system’s configuration.If the drive does not already have drive railsattached, attach a drive rail to each side of the drive.Orient the drive rails as shown in Figure 9-6. Secureeach drive rail to the drive with a screw in each ofthe lower slotted screw holes on the drive rail.Figure 9-6. Attaching Drive Rails2. Remove the computer covers and front bezel.See “Removing the Computer Covers” and “Remov-ing the Front Bezel” in Chapter 7.3. Slide the new drive into its bay until it snapssecurely into place.If necessary, you can adjust drive alignment byrepositioning one or both rails.4. Connect a DC power cable and one of the connec-tors on the Ultra/Narrow SCSI cable to the backof the drive (see Figure 9-7).If other installed drives are in the way, temporarilymove them out of the way. Press in on the plasticdrive rails at the front of the bay to disengage adrive, and then slide the drive slightly toward thefront of the chassis.CAUTION: Dell recommends that you use onlySCSI cables purchased from Dell. SCSI cables pur-chased elsewhere are not guaranteed to workreliably with Dell PowerEdge 4200 systems.CAUTION: See “Protecting Against Electro-static Discharge” in the safety instructions atthe front of this guide.
