Precautions_
2
1-2-1 General Servicing Precautions
(1) a. Always unplug the instrument’s AC powercord from the AC power source before (1) re-moving or reinstalling
any component, circuit board, module or any other instrument assembly, (2) disconnecting any instrument
electrical plug or other electrical connection, (3) connecting a test substitute in parallel with an electrolytic
capacitor in the instrument.
b. Do not defeat any plug/socket B+ voltage interlocks with which instruments covered by this service manual might be
equipped.
c. 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.
d. Always connect a test instrument’s ground lead to the instrument chassis ground before connecting the test instrument
positive lead. Always remove the test instrument ground lead last.
(2) The service precautions are indicated or printed on the cabinet, chassis or components. When servicing, follow the printed or
indicated service precautions and service materials.
(3) The components used in the unit have a specified flame resistance and dielectric strength. When replacing components, use
components which have the same ratings. Components identified by shading, by( ) or by ( ) in the circuit diagram are
important for safety or for the characteristics of the unit. Always replace them with the exactreplacement components.
(4) An insulation tube or tape is sometimes used and some components are raised above the printed wiring board for safety. The
internal wiring is sometimes clamped to prevent contact with heating components. Install such elements as they were.
(5) After servicing, always check that the removed screws, components, and wiring have been installed correctly and that the
portion around the serviced part has not been damaged and so on. Further, check the insulation between the blades of the
attachment plug and accessible conductive parts.
thermally hot parts), (3) the AC supply, (4) high voltage, and (5) antenna wiring. Always inspect in all areas
for pinched, out-of-place, or frayed wiring, Do not change spacing between a component and the printed-
circuit board. Check the AC power cord for damage.
5) Components, parts, and/or wiring that appear have overheated or that are otherwise damaged should be
replaced with components, parts wiring that meet original specifications. Additionally, determine the cause of
overheating and/or damage and, if necessary, take corrective action to remove any potential safety hazard.
6) Product Safety Notice-Some electrical and mechanical parts have special safety-related characteristics which
are often not evident from visual inspection, nor can the protection they give necessarily obtained by replacing
them with components for higher voltage, wattage, etc. Parts that special safety characteristics are identified
shading, an ( )or a ( )on schematics and parts of a substitute replacement that does not same safety
characteristics as the recommended replacement part might create shock, fire other hazards. Product safety is
under review continuously and new instructions are issued whenever appropriate.
Before servicing units covered by this service manual and its supplements, read and follow
the Safety Precautions section of this manual. Note : If unforseen circumstances create conflict
between the following servicing precautions and any of the safety precautions, always follow the
safety precautions. Remember: Safety First.
CAUTION
1-2 Servicing Precautions
Refer to the Safety Precautions section ground lead last.
NOTE
