Warnings, Cautions, And Notes - HP 9020 Service Manual

General Information 1-3
The thermal printer is an optional module. Other hardware options include displays and mass
storage devices. One of three displays can be selected, and flexible disc and fixed disc storage
devices are available. Various combinations of CPU, lOP, and RAM memory boards can configure
the processor stack. Also, several types of HP-IO cards are available for various interfacing require-
ments. Refer to Appendix A for additional information on options.
The HP-IO cards and mass storage controller cards are accessible from the right side of the
computer, and the processor stack cards from the left side. The computer rests on three rubber feet
at the front and two platen-like rollers at the rear. Thus, it can easily be moved for service
accessibility by lifting slightly at the front and rolling forward or backward.
CAUTION
THE WINCHESTER FIXED DISC DRIVE CAN BE DAMAGED WHEN
SUBJECTED TO A SHOCK OF lOG OPERATING OR 20G NON-
OPERATING. TO PREVENT DAMAGE, LOWER COMPUTER GENT-
L Y AFTER MOVING IT ON ITS ROLLERS.
Three dc box fans provide cooling for the computer. The fans draw the air through a grill under the
keyboard and exhaust the air out the back of the computer. One fan is integral to the processor
stack. The other fans are mounted to the chassis, one in the power supply area and one in the I/O
card cage area. The
1/0
card cage fan operates at constant speed. The other two fans are variable,
increasing in speed as the temperature increases. The computer shuts down if the temperature rises
to 100°C in the stack or to 97°C in the power supply.
Warnings, Cautions, and Notes
Warnings, cautions, and notes are used throughout this manual. Warnings call attention to potential
hazards for personnel. Cautions call attention to potential hazards for equipment. Notes emphasize
important information or instructions.
Although all warnings, cautions, and notes are important, one warning and one caution are in-
cluded here to acquaint you with computer considerations.
WARNING
DISCHARGE POWER SUPPLY CAPACITORS USING POWER
SUPPLY DISCHARGE TOOL, PART NUMBER 09855-67004, BE-
FORE REMOVING POWER SUPPLY FROM COMPUTER. FAILURE
TO FOLLOW THIS PROCEDURE COULD RESULT IN EXPOSURE
TO LETHAL SHOCK HAZARD.
CAUTION
TO PREVENT DAMAGE DUE TO ELECTROSTATIC DISCHARGE
(ESD), FOLLOW THE PROCEDURES PROVIDED IN CHAPTER 4.