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Generally, it is not needed to clean the tube surface. However, if necessary, its surface can be
cleaned with a dry cotton cloth after cutting off the power. Don't use any cleanser. If using hard
clothe, the tube surface will be damaged.
CAUTION: Before servicing receivers covered by this service manual and its supplements and
addenda, read and follow the SAFETY PRECAUTIONS.
Warning and Cautions
♦NOTE: If unforeseen circumstances create conflict between the following
servicing precautions and any of the safety precaution, always follow the safety precautions.
Remember: Safety First.
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
assembly of the receiver.
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 substitution part or incorrect installation polarity of electrolytic
capacitors may result in an explosion hazard.
d. Discharging the picture tube anode.
2). Test high voltage only by measuring it with an appropriate high 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). Discharge the picture tube anode only by (a) first connecting one end of an
insulated clip lead to the degaussing or keen quasar grounding system
shield at a point where the picture tube socket tube anode button, using an
insulating handle to avoid personal contact with high voltage.
4). Do not spray chemicals on or near this receiver or any of its assemblies.
5). 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 nonabrasive applicator; 10% (by volume) Acetone and 90%
(by volume) isopropyl (90% - 99% strength).
CAUTION: This is a flammable mixture. Unless specified otherwise in this service manual,
lubrication of contacts is not required.
6). Do not defeat any plug/socket B+ voltage interlocks with which
receivers covered by this service manual might be equipped.
7). 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.
8). Always connect the test receiver ground lead to the receiver chassis ground
before connecting the test receiver positive lead.
9). 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.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged easily by static electricity.
Such components are usually 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
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