Precautions
1-2 Servicing Precautions
Warning1: First read the OSafety Precautions� section of this manual. If some unforeseen circumstance creates a conflict between
the servicing and safety precautions, always follow the safety precautions.
Warning2: An electrolytic capacitor installed with the wrong polarity might explode.
1. Servicing precautions are printed on the 5. Check the insulation between the blades of the
cabinet. Follow them.AC plug and accessible conductive parts
(examples: metal panels, input terminals and
2. Always unplug the unitOs AC power cord fromearphone jacks).
the AC power source before attempting to:
(a) Remove or reinstall any component or 6. Insulation Checking Procedure: Disconnect the
assembly, (b) Disconnect an electrical plug orpower cord from the AC source and turn the
connector, (c) Connect a test component inpower switch ON. Connect an insulation
parallel with an electrolytic capacitor.resistance meter (500V) to the blades of the AC
plug.
3. Some components are raised above the printed
circuit board for safety. An insulation tube orThe insulation resistance between each blade
tape is sometimes used. The internal wiring isof the AC plug and accessible conductive parts
sometimes clamped to prevent contact with(see above) should be greater than 1 megohm.
thermally hot components. Reinstall all such
elements to their original position.7. Never defeat any of the B+ voltage interlocks.
Do not apply AC power to the unit (or any of
4. After servicing, always check that the screws,its assemblies) unless all solid-state heat sinks
components and wiring have been correctlyare correctly installed.
reinstalled. Make sure that the portion around
the serviced part has not been damaged.8. Always connect a test instrumentOs ground
lead to the instrument chassis ground before
connecting the positive lead; always remove
the instrumentOs ground lead last.
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