Before Repair; Protection Circuitry - Panasonic SA-AK58 Service Manual

2. Before Repair

1. Turn off the power supply. Using a 10 , 10W resistor, connect
both ends of power supply capacitors (C571 - 574, 558) in order to
discharge the voltage.
2. Before turning the power supply on, after completion of repair,
slowly apply the primary voltage by using a power supply voltage
controller to make sure that the consumed current at 50Hz in NO
SIGNAL mode should be shown below with respect to supply
voltage 230/230-240V.
Power supply AC230 - 240V,
voltage 50Hz
Consumed Less than
current 350mA

3. Protection Circuitry

The protection circuitry may have operated if either of the following conditions are noticed:
- No sound is heard when the power is switched 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. Switch OFF the power.
2. Determine the cause of the problem and correct it.
3. Switch ON the power once again.
Note:
When the protection circuitry functions, the unit will not operate
unless the power is first switched OFF and ON again.
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