Before Use (For Gc Only); Before Repair And Adjustment; Protection Circuitry - Panasonic SA-VK31GC Service Manual

2 Before Use (For GC Only)

Be sure to disconnect the mains cord before adjusting the voltage selector.
Use a minus(-) screwdriver to set the voltage selector (on the rear panel) to the voltage setting for the area in which the unit will
be used. (If the power supply in your area is 117V or 120V, set to the "127V" position.)
Note that this unit will be seriously damaged if this setting is not made correctly. (There is no voltage selector for some countries,
the correct voltage is already set.)

3 Before Repair and Adjustment

Disconnect AC power, discharge Power Supply Capacitors C950, C5820 and C5820 through a 10Ω, 5W resistor to ground.
DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy solid state devices.
After repairs are completed, restore power gradually using a variac, to avoid overcurrent.
Current consumption at AC 110V, 50/60 Hz and AC 240V, 50 Hz in NO SIGNAL mode should be ~650mA and ~600mA
respectively.

4 Protection Circuitry

The protection circuitry may have operated if either of the following conditions are noticed:
· 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.
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SA-VK31GC / SA-VK31GS