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- No sound is heard when the power is turned on.
- Sound stops during a performance.
The function of this circuitry is to prevent circuitry damage if, for example, the positive and negative
speaker connection wires are
"shorted", or if speaker systems with an impedance less than the indicated rated impedance of the
amplifier are used.
If this occurs, follow the procedure outlines below:
1. Turn off the power.
2. Determine the cause of the problem and correct it.
3. Turn on the power once again after one minute.
Note :
When the protection circuitry functions, the unit will not operate unless the power is first turned off and
then on again.
2. Prevention of Electro Static Discharge (ESD) to
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged easily by electricity. Such components
commonly are called Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are
integrated circuits and some field-effect transistors and semiconductor "chip" components. The
following techniques should be used to help reduce the incidence of component damage caused by
electro static discharge (ESD).
1. Immediately before handling any semiconductor component or
semiconductor-equiped assembly, drain off any ESD on your body by
touching a known earth ground. Alternatively, obtain and wear a
commercially available discharging ESD wrist strap, which should be
removed for potential shock reasons prior to applying power to the unit
under test.
2. After removing an electrical assembly equiped with ES devices, place
the assembly on a conductive surface such as aluminium foil, to
prevent electrostatic charge build up or exposure of the assembly.
3. Use only a grounded-tip soldering iron to solder or unsolder ES
devices.
4. Use only an anti-static solder remover device. Some solder removal
devices not classified as "anti-static (ESD protected)" can generate
electrical charge to damage ES devices.
5. Do not use freon-propelled chemicals. These can generate electrical
charges sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective package
until immediately before you are ready to install it. (Most replacement
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