Before Repair And Adjustment; Protection Circuitry; Safety Part Information - Panasonic SA-NS55P Service Manual

1.2.

Before Repair and Adjustment

Disconnect AC power, discharge Power Supply Capacitors C321, C322, C323, C324, C325, C507, C520 and C611 through a 10Ω,
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
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.
Reference No.
T501
T502
Z500
F1
JK500
RL501
A2
L270
L271
L470
L471
L500
FP502
FP600
FP601
R513
Part No.
G4CYAYY00149
G4CYAYY00065
ERZVA5Z471
K5D162AQ0004
K2AB2B000007
K6B1AEA00015
K2CB2CB00018
G0AR76Y00003
G0AR76Y00003
G0AR76Y00003
G0AR76Y00003
G0B371HA0005
K5G202A00044
K5G502A00039
K5G502A00039
ERC12UGK335D
Table 1
Part Name & Description
TRANSFORMER
SUB TRANSFORMER
ZENER
1.6A FUSE
JK AC INLET
POWER RELAY
AC CORD
CHOKE COIL
CHOKE COIL
CHOKE COIL
CHOKE COIL
LINE FILTER
FUSE PROTECTOR
FUSE PROTECTOR
FUSE PROTECTOR
3.3M 1/2W
5
SA-NS55P
in the
Remarks
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]
[M]