Panasonic SBWA-520-GC Service manual

Specification

n Active subwoofer

Type 1 way, 1 speaker system (Bass

reflex)

Speaker unit(s) Impedance 4 Ω

Woofer 17 cm cone type

Output sound pressure 80 dB/W (1.0 m)

Frequency range 32 Hz-220 Hz (-16 dB)

36 Hz-190 Hz (-10 dB)

Dimensions (W x H x D) 209 x 361 x 463 mm

Mass 11 kg

n General

Power supply AC 110/127/220-230/240 V,

50/60 Hz

Power consumption 220 W

Power consumption in standby mode

0.9 W

Active Subwoofer System

SB-WA520GC

Colour

(S)... Silver Type

n System : SC-HT520GC

Active Subwoofer: SB-WA520GC

n System : SC-HT520GCP

Active Subwoofer: SB-WA520GC

n System : SC-HT520GCS

Active Subwoofer: SB-WA520GC

n System : SC-HT520GS

Active Subwoofer: SB-WA520GC

ORDER NO. MD0403115C3

Music Center: SA-HT520GC

Satellite speakers: SB-HT520P

Music Center: SA-HT520GCP

Satellite speakers: SB-HT520P

Music Center: SA-HT520GCS

Satellite speakers: SB-HT520P

Music Center: SA-HT520GS

Satellite speakers: SB-HT520P

Note :

Specifications are subject to change without notice.

Mass and dimensions are approximate.

SB-HT520P-S consists of :

SB-FS520P-S x 4 and SB-PC520P-S x 1

CONTENTS

Page Page

1 Safety Precautions

1.1. GENERAL GUIDELINES

2 Before Use

3 Handling the Lead-free Solder

3.1. About lead free solder (PbF)

SB-WA520GC

4 Before Repair and Adjustment 4

5 Protection Circuitry

6 Connection of the Speaker Cables

7 Connection of the Wiring Diagram

8 Disassembly Procedure

8.1. Disassembly flow chart

8.2. Disassembly of the Speaker Unit and Checking of the

P.C.B.s.

9 Block Diagram

10 Schematic Diagram

11 Printed Circuit Board

12 Wiring Connection Diagram

13 Illustration of IC 痴, Transistors and Diodes

14 Parts Location and Replacement Parts List

14.1. Cabinet

14.2. Electrical Parts List

14.3. Packing Materials & Accessories Parts List

14.4. Packaging

SB-WA520GC

1 Safety Precautions

1.1. GENERAL GUIDELINES

1. When servicing, observe the original lead dress. If a short circuit is found, replace all parts which have been overheated or damaged by the short circuit.

2. After servicing, see to it that all the protective devices such as insulation barriers, insulation papers shields are properly installed.

3. After servicing, make the following leakage current checks to prevent the customer from being exposed to shock hazards.

1.1.1. LEAKAGE CURRENT COLD CHECK

1. Unplug the AC cord and connect a jumper between the two prongs on the plug.

2. Measure the resistance value, with an ohmmeter, between the jumpered AC plug and each exposed metallic cabinet part on the equipment such as screwheads, connectors, control shafts, etc. When the exposed metallic part has a return path to the chassis, the reading should be between 1MΩand 5.2Ω. When the exposed metal does not have a return path to the chassis, the reading must be

Fig. 1

1.1.2. LEAKAGE CURRENT HOT CHECK (See Figure 1.)

1. Plug the AC cord directly into the AC outlet. Don not use an isolation transformer for this check.

2. Connect a 1.5kΩ, 10 watts resistor, in parallel with a 0.15µF capacitors, between each exposed metallic part on the set and a

good earth ground such as a water pipe, as shown in Figure 1.

3. Use an AC voltmeter, with 1000 ohms/volt or more sensitivity, to measure the potential across the resistor.

4. Check each expose d metallic part, and measure the voltage at each point.

5. Reverse the AC plug in the AC outlet and repeat each of the above measurements.

6. The potential at any point should not exceed 0.75 volts RMS. A leakage current tester (Simpson Model 229 or equivalent) may be used to make the hot checks, leakage current must not exceed 1/2 milliamp. In case a measurement is outside of the limits specified, there is a possibility of a shock hazard, and the equipment should be repaired and rechecked before it is returned to the customer.

SB-WA520GC

2 Before Use

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 Handling the Lead-free Solder

3.1. About lead free solder (PbF)

Distinction of PbF P.C.B. :

P.C.B.s (manufactured) using lead free solder will have a PbF stamp on the P.C.B.

Caution:

· Pb free solder has a higher melting point that standard solder; Typically the melting point is 50 - 70°F (30 - 40°C) higher.

Please use a high temperature soldering iron. In case of the soldering iron with temperature control, please set it to 700 ± 20°F (370 ± 10°C).

· Pb free solder will tend to splash when heated too high (about 1100°F/600°C).

· W hen soldering or unsoldering, please completely remove all of the solder on the pins or solder area, and be sure to heat the

soldering points with the Pb free solder until it melts enough.

4 Before Repair and Adjustment

Disconnect AC power, discharge Power Supply Capacitors C546, C547, C548, C549 through a 10 Ω, 1 W resistor to ground.

DO NOT SHORT-CIRC UIT 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 consum ption at AC 127V, 50/60Hz in NO SIGNAL mode should be ~480 mA and

Current consum ption at AC 240V, 50Hz in NO SIGNAL mode should be ~250 mA respectively.

5 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.

· 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.

SB-WA520GC

6 Connection of the Speaker Cables

· Be sure to connect speaker cables before connec ting the AC power supply cord.

· The load impedance of any speaker used with this unit must be 4Ω.

· Be sure to connect the cable from the right speaker to the right terminal and the cable from the left speaker to the left terminal.

1. Strip off the outer covering, and twist the center conductor. Make sure the bare ends of the wires are not unravelled. (If they are, twist them tight again.)

2. Insert the wire to the rear panel of the unit and close the lever.

Notes :

· To prevent damage to circuitry, never short-circuit positive (+) and negative (-) speaker wires.

· Be sure to connect only positive (red) wires to positive (+) terminals and negative (black) wires to negative (-) terminals.

SB-WA520GC

7 Connection of the Wiring Diagram

SB-WA520GC

8 Disassembly Procedure

“ATTENTION SERVICER”

Some chassis components may have sharp edges.

Be careful when disassembling and servicing.

1. This section describes procedures for checking the operation of the major printed circuit boards and replacing the

main components.

2. For reassembly after operation checks or replacement, reverse the respec tive procedures.

Special reassembly procedures are described only when required.

3. Select items from the following index when checks or replacement are required.

Contents

· Disasse mbly of the Speaker Unit

· Main Component Replacement Procedures

8.1. Disassembly flow chart

The following chart is the procedure for disassembling the casing and inside parts for internal inspection when carrying out the servicing.

To assemble the unit, reverse the steps shown in the chart below.

SB-WA520GC

8.2. Disassembly of the Speaker Unit and Checking of the P.C.B.s.

guide.

Step 5: Remove the screws from the subwoofer.

Step 1: Remove all the screws.

Step 2: Remove the stand base.

Step 3: Remove all the screws from the bottom of the speaker

unit.

· Disassembly of Power Amp unit.

Steps 6 & 7: Remove the screws.

Step 4: Remove the screws from the rear panel’s speaker unit

Step 8: Pull out the Power Amp unit slightly as shown.

(Note: Be careful of attach wire at CN506).

SB-WA520GC

Step 9: Release the connector CN506 then pull out the entire

Power Amp unit.

Steps 10 & 11: Remove all the screws.

Step 13: Remove the screws from the AC Inlet

P.C.B.

Steps 14 & 15: Remove the screws.

Step 12: Releas e the connector CN507 to remove the rear

panel.

· Checking for the Power and AC Inlet P.C.B.

Step 16: Place the Power P.C.B. and the AC Inlet P.C.B. as shown for checking.

· Checking for the Transformer P.C.B.

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