Service manual

A. Introduction to This Section
This section of the manual describes preventive
maintenance, handling precautions, and some basic
repair procedures and techniques. Each of these top-
ics provides information vital to the successful
operation and maintenance of your radio.
B. Preventive Maintenance
The ASTRO Digital SABER radios do not require
a scheduled preventive maintenance program; howev-
er, periodic visual inspection and cleaning is
recommended.
1. Inspection
Check that the external surfaces of the radio are
clean, and that all external controls and switches
are functional. A detailed inspection of the interior
electronic circuitry is not needed.
2. Cleaning
The following procedures describe the recom-
mended cleaning agents and the methods to be
used when cleaning the external and internal sur-
faces of the radio. External surfaces include the
front cover, housing assembly, and battery case.
These surfaces should be cleaned whenever a
periodic visual inspection reveals the presence of
smudges, grease, and/or grime. Internal surfaces
should be cleaned only when the radio is disas-
sembled for servicing or repair.
The only recommended agent for cleaning the
external radio surfaces is a 0.5% solution of a mild
dishwashing detergent, such as JOY
®
, in water.
The only factory recommended liquid for cleaning
the printed circuit boards and their components is
isopropyl alcohol (70% by volume).
a. Cleaning External Plastic Surfaces
(The detergent-water solution should be
applied sparingly with a stiff, non-metallic,
short-bristled brush to work all loose dirt away
from the radio. A soft, absorbent, lintless cloth
or tissue should be used to remove the solu-
tion and dry the radio. Make sure that no
water remains entrapped near the connectors,
cracks, or crevices.
b. 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.
Alcohol is a high-wetting liquid and can carry
contamination into unwanted places if an
excessive quantity is used. Make sure that
controls or tunable components are not
soaked with the liquid. Do not use high-pres-
sure air to hasten the drying process, since
this could cause the liquid to puddle and col-
lect 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.
NOTE
Always use a fresh supply of alcohol and a
clean container to prevent contamination by
dissolved material (from previous usage).
C. Handling Precautions
Complementary metal-oxide semiconductor
(CMOS) devices, and other high-technology devices,
are used in this family of radios. While the attributes of
these devices are many, their characteristics make
them susceptible to damage by electrostatic discharge
(ESD) 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, trou-
bleshooting, and repair. Handling precautions are
mandatory for this radio, and are especially important
in low-humidity conditions. DO NOT attempt to disas-
semble the radio without observing the following
handling precautions.
1. Eliminate static generators (plastics, Styrofoam,
etc.) in the work area.
2. Remove nylon or double-knit polyester jackets, roll
up long sleeves, and remove or tie back loose
hanging neckties.
3. Store and transport all static-sensitive devices in
ESD-protective containers.
4. Disconnect all power from the unit before ESD-
sensitive components are removed or inserted
unless otherwise noted.
3
SECTION II. BASIC MAINTENANCE
CAUTION
The effects of certain chemicals and their
vapors can have harmful results on certain plas-
tics. Aerosol sprays, tuner cleaners, and other
chemicals should be avoided.