2
2-6 Safety Check after Repairment
Confirm that the screws, parts and wiring which were removed in order to service are put in the original
positions, or whether there are the positions which are deteriorated around the serviced places serviced or
not. Check the insulation between the antenna terminal or external metal and the AC cord plug blades. And
be sure the safety of that.
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. Do not defeat any plug/socket B+ voltage interlocks with which receivers covered by this service manual
might be equipped.
5. Do not apply AC power to this instrument and/or an
6. 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. Capacitors may result in an explosion hazard.
7. Use with this receiver only the test fixtures specified in this service manual.
CAUTION: Jo not connect the test fixture ground strap to any heat sink in this receiver.
8. Insulation resistance between the cord plug terminals and the eternal exposure metal should be more than
Mohm by using the 500V insulation resistance meter.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid-state) devices can be damaged easily by static electricity. Such components
commonly are called Electrostatically 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 ncidence 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.
To Next Page
Loading...
