Stihl BT 131, Инструкция по эксплуатации

Страница: 5 / 45

5
2. Servicing Precautions
2.1 General Servicing Precautions:
1. Always unplug the receiver AC power cord from the AC power
Source before:
a. Removing or reinstalling any component, circuit board module or any other receiver
assembly.
b. Disconnecting or reconnecting any receiver electrical plug or other electrical connection.
c. Connecting a test substitute in parallel with an electrolytic capacitor in the receiver.
CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic
capacitors may result in an explosion hazard
2. Test high voltage only by measuring it with an appropriate high voltage meter or other
voltage measuring device (DVM, FETVOM, etc) equipped with a suitable high voltage probe.
Do not test high voltage by "drawing an arc".
3. Do not spray chemicals on or near this receiver or any of its assemblies.
4. Unless specified otherwise in this service manual, clean electrical contacts only by
applying the following mixture to the contacts with a pipe cleaner, cotton-tipped stick or
comparable non-abrasive applicator; 10% (by volume) Acetone and 90% (by volume)
isopropyl alcohol (90%-99% strength)
CAUTION: This is a flammable mixture. Unless specified otherwise in this service manual,
lubrication of contacts in not required.
5. Do not defeat any plug/socket voltage interlocks with which receivers covered by this
service manual might be equipped.
6. Do not apply AC power to this instrument and/or any of its electrical assemblies unless all
solid-state device heat sinks are correctly installed.
7. Always connect the test receiver ground lead to the receiver chassis ground before
connecting the test receiver positive lead. Always remove the test receiver ground lead last.
8. Use with this receiver only the test fixtures specified in this service manual. CAUTION: Do
not connect the test fixture ground strap to any heat sink in this receiver.
2.2
Electrostatic Sensitive (ES) Devices:
Some semiconductor (solid-state) devices can be damaged easily by static electricity.
Such components commonly are called Electrostatic Sensitive (ES) Devices. Examples of
typical ES devices are integrated circuits and some field-effect transistors and
semiconductor "chip" components. The following techniques should be used to help
reduce the incidence of component damage caused by static by static electricity.
1. Immediately before handling any semiconductor component or semiconductor-equipped
assembly, drain off any electrostatic charge on your body by touching a known earth
ground. Alternatively, obtain and wear a commercially available discharging wrist strap
device, which should be removed to prevent potential shock reasons prior to applying
power to the unit under test.
2. After removing an electrical assembly equipped with ES devices, place the assembly on a