Sun Microsystems SPARCstation 20, Service Manual

Page: 130 / 266

106 SPARCstation 20 Service Manual • July 1996
c. Remove the DC power harness (labeled P3) from the card guide clips and
disconnect the DC power harness from the SCSI backplane.
9. Remove the power supply.
See “Removing the Power Supply” on page 55.
10. Disconnect the DC power harness (labeled P1) from the power supply and
carefully remove the harness from the system chassis.
Installing the DC Power Harness (SunCD 4 Drive-
Type Chassis)
Caution – Use proper ESD grounding techniques when handling components. Wear
an antistatic wrist strap and use an ESD-protected mat. Store ESD-sensitive
components in antistatic bags before placing it on any surface.
Note –
Visual markers are placed on the DC power harnesses to aid cable
alignment. When properly installed, the two colored tape marks on the P1 (power
supply) harness should straddle the chassis wall metal cable clips that are nearest to
the system board. The P2 (CD-ROM drive) harness should lie under the second
chassis floor metal cable clip. The second colored tape mark (farthermost from the P3
connector) of the P3 (SCSI backplane) harness should be centered under the second
plastic cable guide clip. The P4 (diskette drive) harness should be threaded through
the chassis wall, with the diskette data cable, and located under the first metal
chassis floor cable clip.
1. Place the power supply harness, SCSI backplane DC power harness, diskette
drive DC power harness, CD-ROM DC power harness, and SCSI data cable as
follows (
FIGURE 8-29
):
a. Route the power supply harness (labeled P1) through the metal cable clips on
the chassis wall.
Note –
The two colored tape marks on the DC power harness should straddle the
cable clips.
b. Route the SCSI backplane DC power harness (labeled P3) under the plastic
cable clips on the card guide to the SCSI backplane.
c. Thread the diskette drive DC power harness (labeled P4) through the hole in
the chassis wall with the diskette data cable.