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