HP EliteDesk 800 G2 Desktop Mini, HP EliteDesk 705 G2 Desktop Mini, HP ProDesk 600 G2 Desktop Mini, HP ProDesk 400 G2 Desktop Mini, HP MP9 G2 Retail System - Maintenance and Service Guide

3 Routine care, SATA drive guidelines, and
disassembly preparation
This chapter provides general service information for the computer. Adherence to the procedures and
precautions described in this chapter is essential for proper service.
CAUTION: When the computer is plugged into an AC power source, voltage is always applied to the system
board. You must disconnect the power cord from the power source before opening the computer to prevent
system board or component damage.
Electrostatic discharge information
A sudden discharge of static electricity from your nger or other conductor can destroy static-sensitive devices
or microcircuitry. Often the spark is neither felt nor heard, but damage occurs. An electronic device exposed to
electrostatic discharge (ESD) may not appear to be aected at all and can work perfectly throughout a normal
cycle. The device may function normally for a while, but it has been degraded in the internal layers, reducing its
life expectancy.
Networks built into many integrated circuits provide some protection, but in many cases, the discharge contains
enough power to alter device parameters or melt silicon junctions.
Generating static
The following table shows that:
●
Dierent activities generate dierent amounts of static electricity.
●
Static electricity increases as humidity decreases.
Relative Humidity
Event 55% 40% 10%
Walking across carpet
Walking across vinyl oor
Motions of bench worker
Removing DIPs from plastic tube
7,500 V
3,000 V
400 V
400 V
15,000 V
5,000 V
800 V
700 V
35,000 V
12,000 V
6,000 V
2,000 V
Removing DIPs from vinyl tray
Removing DIPs from Styrofoam
Removing bubble pack from PCB
Packing PCBs in foam-lined box
2,000 V
3,500 V
7,000 V
5,000 V
4,000 V
5,000 V
20,000 V
11,000 V
11,500 V
14,500 V
26,500 V
21,000 V
These are then multi-packaged inside plastic tubes, trays, or Styrofoam.
NOTE: 700 volts can degrade a product.
12 Chapter 3 Routine care, SATA drive guidelines, and disassembly preparation