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GE H
EALTHCARE
D
5336113-1EN, R
IRECTION
Section 1.3 Electrostatic discharge (ESD)
1.3.1 Important ESD considerations when working on a mobile system
1.3.2 Generating static
Page 28
10
EVISION
8.
Re-energize equipment and follow safe startup procedures.
9.
Notify affected persons that energy has been restored.
A sudden discharge of static electricity from your finger 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) might not appear to be affected at all
and can work perfectly throughout a normal cycle. The device can 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.
Static Discharge Risk to Components
If you are using a static mat or wrist strap, be sure to connect the mat and strap to machine ground,
not earth ground. This is necessary to isolate yourself from earth ground and equalize your potential
with the machine.
ESD damage prevention includes these steps:
1.
Perform LOTO.
2.
Verify that the AC plug is not connected to an energy source/outlet.
3.
Connect ground mat and wrist strap assembly to frame connection point of the mobile unit.
The following table shows that different activities generate different amounts of static electricity, and
that static electricity increases as humidity decreases.
Table 1-2
Event
Walking across carpet
Walking across vinyl floor
Motions of bench worker
Removing bubble pack from PCB
Packing PCBs in foam-lined box
Many electronic components are sensitive to ESD. Circuitry design and structure determine the
degree of sensitivity. The following packaging and grounding precautions are necessary to prevent
damage to electric components and accessories.
•
Transport products in static-safe containers to avoid hand contact.
Section 1.3 Electrostatic discharge (ESD)
O
PTIMA
Relative humidity
55%
40%
7,500 V
15,000 V
3,000 V
5,000 V
400 V
800 V
7,000 V
20,000 V
5,000 V
11,000 V
XR200
/XR220
AMX
AMX
I
M
NSTALLATION
ANUAL
10%
35,000 V
12,000 V
6,000 V
26,500 V
21,000 V
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