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MAINTENANCE & SERVICE GUIDE
Index page
Removal & Replacement
Removal & Replacement
A sudden discharge of static electricity from a 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) may not
be affected at all and will work perfectly throughout a normal cycle. Or it may function
normally for a while, then degrade 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 table below shows the different amounts of static electricity generated by different
activities .
Event
Walking across
carpet
Walking across
vinyl floor
Motions of bench
worker
Removing DIPS
from plastic tubes
Removing DIPS
from vinyl trays
Removing DIPS
from Styrofoam
Removing bubble
pack from PCBs
Packing PCBs in
foam-lined box
NOTE: 700 volts can degrade a product!
Preventing Electrostatic Damage to Equipment
Many electronic components are sensitive to ESD. Circuitry design and structure
determine the degree of sensitivity. The following proper packaging and grounding
precautions are necessary to prevent damage:
Protect all electrostatic parts and assemblies with conductive or
approved containers or packaging.
Keep electrostatic sensitive parts in their containers until they arrive
at static-free stations.
Place items on a grounded surface before removing them from their
container.
Always be properly grounded when touching a sensitive component
or assembly.
Place reusable electrostatic-sensitive parts from assemblies in
protective packaging or conductive foam.
Use transporters and conveyors made of antistatic belts and metal roller bushings.
Mechanized equipment used for moving materials must be wired to ground and proper
materials selected to avoid static charging. When grounding is not possible, use an
ionizer to dissipate electric charges.
Preventing Damage to Drives
To prevent static damage to hard drives, use the following precautions:
Handle drives gently, using static-guarding techniques.
Store drives in the original shipping containers.
Avoid dropping drives from any height onto any surface.
Handle drives on surfaces that have at least one inch of shock-proof
foam.
Always place drives PCB assembly side down on the foam.
Grounding Methods
The method for grounding must include a wrist strap or a foot strap at a grounded
workstation. When seated, wear a wrist strap connected to a grounded system. When
standing, use footstraps and a grounded floor mat.
Method
Voltages
Grounding Workstations
To prevent static damage at the workstation, use the following precautions:
Cover the workstation with approved static-dissipative material. Provide a wrist strap
connected to the work surface and properly grounded tools and equipment.
Use static-dissipative mats, heel straps, or air ionizers to give added protection.
Handle electrostatic sensitive components, parts, and assemblies by the case or PCB
laminate. Handle them only at static-free workstations.
Avoid contact with pins, leads, or circuitry.
Turn off power and input signals before inserting and removing connectors or test
equipment.
Use fixtures made of static-safe materials when fixtures must directly contact
dissipative surfaces.
Keep work area free of nonconductive materials such as ordinary plastic assembly aids
and Styrofoam.
Use field service tools, such as cutters, screwdrivers, and vacuums, that are
conductive.
Use a portable field service kit with a static dissipative vinyl pouch that folds out of a
work mat. Also use a wrist strap and a ground cord for the work surface. Ground the
cord to the chassis of the equipment undergoing test or repair.
Grounding Equipment
Use the following equipment to prevent static electricity damage to the equipment:
Wrist Straps are flexible straps with a minimum of 1 megohm ±10% resistance to the
ground cords. To provide proper ground, a strap must be worn snug against the skin.
On grounded mats without banana-plug connectors, connect a wrist strap with
alligator clips.
Heelstraps/Toestraps/Bootstraps can be used at standing workstations and are
compatible with most types of boots and shoes. On conductive floors or dissipative
floor mats, use them on both feet with a minimum of 1 megohm resistance between
operator and ground. To be effective, the conductive strips must be worn in contact
with the skin.
Recommended Materials and Equipment
Other materials and equipment that are recommended for use in preventing static
electricity include:
Antistatic tape
Antistatic smocks, aprons, or sleeve protectors
Conductive bins, and other assembly or soldering aids
Conductive foam
Conductive tabletop workstations with ground cord of 1 megohm of resistance
Static dissipative table or floor mats with hard tie to ground
Field service kits
Static awareness labels
Wrist straps and footwear straps providing 1 megohm ±10% resistance
Material handling packages
Conductive plastic bags
Conductive plastic tubes
Conductive tote boxes
Metal tote boxes
Opaque shielding bags
Transparent metallized shielding bags
Transparent shielding tubes
Continue with Preliminary Procedures:
Service Considerations
Preparing Computer for Disassembly
Revised: September 17th, 1999
for Prosignia 320 Series Computer
Preface
-or-
Jumper & Switch Settings
Electrostatic Discharge
Relative Humidity
35,000 V
12,000 V
6,000 V
2,000 V
11,500 V
14,500 V
26,000 V
21,000 V
Static-Shielding Protection Levels
Antistatic
Carbon-Loaded
Plastic
1,500
Product Description
Notice
Troubleshooting
10%
40%
15,000 V
5,000 V
800 V
700 V
4,000 V
5,000 V
20,000 V
11,000 V
Plastic
7,500
Illustrated Parts Catalog
55%
7,500 V
3,000 V
400 V
400 V
2,000 V
3,500 V
7,000 V
5,000 V
Metallized
Laminate
15,000
Specifications
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Troubleshooting
