111707 Service Manual
6
Precautions
1-2 Servicing Precautions
WARNING : An electrolytic capacitor installed with the wrong polarity might explode.
Caution :
Before servicing instruments covered by this service manual and its supplements,
read and follow the Safety Precautions section of this manual.
Note : If unforeseen circumstances create conflict between the following servicing preautions
and any of the safety precautions, always follow the safety precautions.
1-2-1. General Servicing Precautions
1. Servicing precautions are printed on the cabinet, and should be followed closely.
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 PCB plugs or connectors,
(c) connect a test component in paralled 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. 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.
