1-2. Servicing Precautions
An electrolytic capacitor installed with the wrong polarity might explode.
Before servicing units covered by this service manual, read and follow the Safety Precautions section of
If unforeseen circumstances create conflict between the following servicing precautions and any of the
safety precautions, always follow the safety precautions.
1-2-1. General Servicing Precautions
Always unplug the unit's AC power cord from the AC power source and disconnect the DC Power Jack before
attempting to: (a) remove or reinstall any component or assembly, (b) disconnect PCB plugs or connectors, (c) connect
a test component in parallel with an electrolytic capacitor.
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.
After servicing, always check that the screws, components and wiring have been correctly reinstalled. Make sure that
the area around the serviced part has not been damaged.
Check the insulation between the blades of the AC plug and accessible conductive parts (examples: metal panels, input
terminals and earphone jacks).
Insulation Checking Procedure: Disconnect the power cord from the AC source and turn the power switch ON. Connect
an insulation resistance meter (500 V) to theblades 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.
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.