Safe Handling Of Cmos Devices; Precautions - Motorola MCS 2000 Service Instructions Manual

Note
Safe Handling
of CMOS
Devices
!
C a u t i o n

Precautions

2-2 Basic Maintenance
Upon completion of the cleaning process, use a soft, absorbent, lint-free cloth
to dry the area. Do not brush or apply any isopropyl alcohol to the frame,
front cover, or back cover.
Always use a fresh supply of alcohol and a clean container to prevent
contamination by dissolved material (from previous usage).
Complementary metal-oxide semiconductor (CMOS) devices are used in
this family of radios. While the attributes of CMOS are many, their
characteristics make them susceptible to damage by electrostatic or high
voltage charges. Damage can be latent, resulting in failures occurring
weeks or months later. Therefore, special precautions must be taken to
prevent device damage during disassembly, troubleshooting, and repair.
Handling precautions are mandatory for CMOS circuits, and are especially
important in low humidity conditions. DO NOT attempt to disassemble
the radio without observing the following handling precautions.
12. Eliminate static generators (plastics, styrofoam, etc.) in the work area.
13. Remove nylon or double-knit polyester jackets, roll up long sleeves, and
remove or tie back loose hanging neckties
14. Store and transport all static-sensitive devices in ESD-protective
containers.
15. If at all possible, handle CMOS devices by the package and not by the
leads. Prior to touching the unit, touch an electrical ground to remove
any static charge that you may have accumulated. The package and
substrate may be electrically common. If so, the reaction of a discharge
to the case would cause the same damage as touching the leads.
16. Disconnect all power from the unit before ESD-sensitive components are
removed or inserted unless otherwise noted.
17. Use a static-safeguarded workstation, which can be accomplished
through the use of an anti-static kit (Motorola part number 01-
80386A82). This kit includes a wrist strap, two ground cords, a static-
control table mat and a static-control floor mat. For additional
information, refer to Service and Repair Note SRN F1052, "Static Control
Equipment for Servicing ESD Sensitive Products", available from
Motorola Literature Distribution 2290 Hammond Drive Schaumburg, IL
60173 (847) 576-2826
When these items are not readily available, observing the following
techniques will minimize chance of damage.
- If a static-sensitive device is to be temporarily set down, use a
conductive surface for placement of the device.
- Make skin contact with a conductive work surface first and maintain
this contact when the device is set down or picked up.