Leakage
Leakage
Leakage
Leakage Current
Current
Current
Current Hot
Hot
Hot
Hot Check
Check
Check
Check circuit
circuit
circuit
circuit
SERVICING
SERVICING
SERVICING
SERVICING PRECAUTIONS
PRECAUTIONS
PRECAUTIONS
PRECAUTIONS
CAUTION
CAUTION
CAUTION
CAUTION
: Before servicing receivers covered by this service manual and its supplements and addenda, read and follow
SAFETY PRECAUTIONS on page 3 of this publication.
NOTE:
NOTE:
NOTE:
NOTE:
If unforeseen circumstances create conflict between the following servicing precautions and any of the safety
precautions on page 3 of this publication, always follow the safety precautions. Remember: Safety First.
General
General
General
General Servicing
Servicing
Servicing
Servicing Precautions
Precautions
Precautions
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
CAUTION
CAUTION
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
CAUTION
CAUTION
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 B+ 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 ar
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:
CAUTION:
CAUTION:
CAUTION:
Do not connect the test fixture ground strap to any heat sink in this receiver.
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 incidence of
component damage caused by static by static electricity.
