Panasonic SA-NS55P, Service Manual

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1.2. Before Repair and Adjustment
Disconnect AC power, discharge Power Supply Capacitors C321, C322, C323, C324, C325, C507, C520 and C611 through a 10
Ω
,
1W 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 120 V, 60 Hz in NO SIGNAL mode should be ~250 mA.
1.3. Protection Circuitry
The protection circuitry may have operated if either of the following conditions are noticed:
· No sound is heard when the power is 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.
1.4. Safety Part Information
Safety Parts List:
There are special components used in this equipment which are important for safety.These parts are marked by in the
Schematic Diagrams & Replacement Parts List. It is essential that these critical parts should be replaced with manufacturer’s
specified parts to prevent shock, fire or other hazards. Do not modify the original design without permission of manufacturer.
Table 1
Reference No. Part No. Part Name & Description Remarks
T501 G4CYAYY00149 TRANSFORMER [M]
T502 G4CYAYY00065 SUB TRANSFORMER [M]
Z500 ERZVA5Z471 ZENER [M]
F1 K5D162AQ0004 1.6A FUSE [M]
JK500 K2AB2B000007 JK AC INLET [M]
RL501 K6B1AEA00015 POWER RELAY [M]
A2 K2CB2CB00018 AC CORD [M]
L270 G0AR76Y00003 CHOKE COIL [M]
L271 G0AR76Y00003 CHOKE COIL [M]
L470 G0AR76Y00003 CHOKE COIL [M]
L471 G0AR76Y00003 CHOKE COIL [M]
L500 G0B371HA0005 LINE FILTER [M]
FP502 K5G202A00044 FUSE PROTECTOR [M]
FP600 K5G502A00039 FUSE PROTECTOR [M]
FP601 K5G502A00039 FUSE PROTECTOR [M]
R513 ERC12UGK335D 3.3M 1/2W [M]
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SA-NS55P