Motorola P100 Series, Detailed Service Manual, Page: 24 / 336

1-2 Introduction
2. Cleaning Internal Circuit Boards and Components
Isopropyl alcohol may be applied with a stiff, non-metallic, short-bristled brush to dislodge
embedded or caked materials located in hard-to-reach areas. The brush stroke should
direct the dislodged material out and away from the inside of the radio. Make sure that
controls or tunable components are not soaked with alcohol. Do not use high-pressure
air to hasten the drying process since this could cause the liquid to collect in unwanted
places. Upon completion of the cleaning process, use a soft, absorbent, lintless cloth to
dry the area. Do not brush or apply any isopropyl alcohol to the frame, front cover, or
back cover.
1.4 Safe Handling of CMOS and LDMOS
Complementary metal-oxide semiconductor (CMOS) devices are used in this family of radios.
CMOS 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 first referring to the CMOS
CAUTION paragraph in the Disassembly and Reassembly section of the manual.
NOTE Always use a fresh supply of alcohol and a clean container to prevent contamination by
dissolved material (from previous usage).
This radio contains static-sensitive devices. Do not open the radio unless you are
properly grounded. Take the following precautions when working on this unit:
• Store and transport all CMOS devices in conductive material so that
all exposed leads are shorted together. Do not insert CMOS devices
into conventional plastic “snow” trays used for storage and
transportation of other semiconductor devices.
• Ground the working surface of the service bench to protect the
CMOS device. We recommend using a wrist strap, two ground
cords, a table mat, a floor mat, ESD shoes, and an ESD chair.
• Wear a conductive wrist strap in series with a 100k resistor to
ground. (Replacement wrist straps that connect to the bench top
covering are Motorola part number 4280385A59).
• Do not wear nylon clothing while handling CMOS devices.
• Do not insert or remove CMOS devices with power applied. Check
all power supplies used for testing CMOS devices to be certain that
there are no voltage transients present.
• When straightening CMOS pins, provide ground straps for the
apparatus used.
• When soldering, use a grounded soldering iron.
• 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.