Panasonic SC-AK48 User manual

●AMPLIFIER SECTION
PMPO 3000W
RMS power output
THD 10%, both channels driven
(HIGH) 40W per channel (6Ω)
(MID) 40W per channel (6Ω)
(LOW) 120W per channel (6Ω)
(TOTAL) 200W per channel (6Ω)
Input sensitivity
AUX 250mA
MIC 0.7mV
Input inpedance
AUX 13.9kΩ
MIC 680Ω
●FM TUNER SECTION
Frequency range 87.50 - 108.00MHz
(50kHz steps)
Sensitivity 2.5µV (IHF)
S/N 26dB 2.2µV
Antenna terminal (s) 75Ω(unbalanced)
●AM TUNER SECTION
Frequency range 552-1629kHz (9kHz steps)
Sensitivity 520-1630kHz (10kHz steps)
S/N 20dB (at 999kHz) 560µV/m
© 2000 Matsushita Electric Industrial Co., Ltd. All
rights reserved. Unauthorized copying and
distribution is a violation of law.
SA-AK48
Colour
(S) ................. Silver Type
Areas
(GC) .............. Asia, Latin America,
Middle East and Africa.
TAPE SECTION : AR2 MECHANISM SERIES
CD SECTION : RAE0152Z-M TRAVERSE DECK
SERIES
SYSTEM : SC-AK48
●CASSETTE DECK SECTION
Track system 4 track, 2 channel
Heads
Record/playback Soild permalloy head
Erasure Double gap ferrite head
Motor DC servo motor
Recording system AC bias 100kHz
Erasing system AC erase 100kHz
Tape speed 4.8cm/s
Frequency response (+3, -6dB) at DECK OUT
NORMAL (TYPE I) 35Hz - 14kHz
HIGH (TYPE II) 35Hz - 14kHz
S/N 50dB (A weighted)
Wow and flutter 0.18% (WRMS)
Fast forward and rewind time Approx. 120 seconds with
C-60 cassette tape
●CD SECTION
Sampling frequency 44.1kHz
Decoding 16 bit linear
Beam source/wave length Semiconductor laser/
780nm
Number of channels Stereo
Frequency response 20Hz - 20kHz (+1dB, -2dB)
Wow and flutter Below measurable limit
Digital filter 8fs
CD Stereo System
Specifications
ORDER No.MD0004060C3

D/A converter MASH (1bit DAC)
●GENERAL
Power supply : AC110V/127V/220V/
230-240V, 50/50Hz
Power consumption 220W
Power consumption in standby
mode
Eco mode on 0.8W
Eco mode off 14W
Dimensions (WxHxD) 270x331x338mm
1 Accessories 3
2 Before Repair 3
3 Protection Circuitry 3
4 Handling Precautions for Traverse Deck 4
4.1. Handling the traverse deck (optical pickup) 4
4.2. Grounding for electrostatic breakdown prevention 4
4.3. Caution when Replacing the Traverse Deck 4
5 Precaution of Laser Diode 5
6 Location of Controls 6
7 Location of Controls for Remote Control Transmitter 7
8 Operation Checks and Component Replacement Procedures
8
8.1. Checking for the main P.C.B. 8
8.2. Disassembly for the CD changer ass’y 9
8.3. Checking for the unit operational condition 11
8.4. Replacement for the traverse deck ass’y 13
8.5. Replacement for the disc tray 16
8.6. Disassembly and reassembly for mechanism base drive
unit 18
8.7. Replacement for the motor ass’y 24
8.8. Replacement for the pinch roller ass’y and head block 25
8.9. Replacement for the CD motor ass’y, capstan belt A,
capstan belt B and winding belt 27
8.10. Replacement for the components parts on the mechanism
P.C.B. 29
8.11. Replacement for the cassette lid ass’y 29
8.12. Measure for tape trouble 30
9 Checking Procedure for Self-operation of Cassette
Mechanism Ass’y 31
9.1. Operation Check Providing with Cassette Tape 31
9.2. Operation Check Not Provided with Cassette Tape 31
Weight 9.0kg
Notes:
1.Specifications are subject to change without notice.
Weight and dimensions are approximate.
2.Total harmonic distortion is measured by the digital spectrum
analyzer.
●SYSTEM
SC-AK48 :
Main unit : SA-AK48
Speakers : SB-AK48
10 Self-Diagnostic Display Function 32
11 Description of Error Code 33
11.1. Error Detection for Cassette Mechanism block 33
11.2. Error Detection for CD/Changer block 33
11.3. Error Detection for Cassette Mechanism block 33
12 CD Test Mode Function 34
13 Measurement and Adjustments 35
13.1. Tuner Section 35
13.2. Cassette Deck Section 36
14 Illustration of ICs, Transistors and Diodes 38
15 Schematic Diagram 39
15.1. Schematic Diagram Notes 39
15.2. Schematic Diagram 40
16 Printed Circuit Board Diagram 58
17 Block Diagram 69
18 Troubleshooting Guide 77
19 Wiring Connection Diagram 79
20 Terminal Function of ICs 81
20.1. IC600 (M38199MF227):System Control and FL Driver 81
20.2. IC701 (AN8839NSBE2):Servo Amp 81
20.3. IC702 (MN662790RSC):Servo Processor/Digital Signal
Processor/Digital Filter/D/A converter 81
20.4. IC703 (AN8739SBE2):Focus Coil/Tracking Coil/Traverse
Motor/SpindleMotor Drive 82
21 Replacement Parts List 83
22 Cabinet Parts Location 95
23 Mechanism Parts Location 97
24 CD Mechanism Parts Location 99
25 Packaging 100
CONTENTS
Page Page
2
SA-AK48

1.Turn off the power supply. Using a 10Ω, 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
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.
current at 50Hz in NO SIGNAL mode should be shown
below with respect to supply voltage 230/230-240V.
Power supply voltage AC230V, 50Hz AC230 - 240V, 50Hz
Consumed current Less than 250mA Less than 250mA
1 Accessories
2 Before Repair
3 Protection Circuitry
3
SA-AK48

The laser diodes in the traverse deck (optical pickup) may
break down due to potential difference caused by static
electricity of clothes or human body.
So, be careful of electrostatic breakdown during repair of the
traverse deck (optical pickup).
4.1. Handling the traverse deck
(optical pickup)
1.The traverse deck (optical pickup) is an extremely high-
precision construction and must not be subjected to impact,
excessive vibration, or other types of rough handling.
2.In order to prevent static electricity damage to the laser
diode, use a short pin or similar tool to short the optical
pickup’s flexible circuit boards after they have been
disconnected from the main circuit board.
3.Handle the flexible circuit boards with care; excessive force
could cause them to be broken.
4.Do not turn the pre-set variable resistor (for adjustment of
the laser power); it has been adjusted at the factory.
(as shown in Fig.1)
Fig.1
4.2. Grounding for electrostatic
breakdown prevention
1.Human body grounding
Use the anti-atatic wrist strap to discharge the static
electricity from your body.
2.Work table grounding
Put a conductive material (sheet) or steel sheet on the area
where the optical pickup is placed, and ground the sheet.
(sa shown in Fig.2)
Fig.2
Caution:
The static electricity of your clothes will not be grounded
through the wrist strap.
So, take care not to let your clothes touch the traverse deck
(optical pickup)
4.3. Caution when Replacing the
Traverse Deck
The traverse deck has a short point shorted with solder protect
the laser diode against electrostatic breakbown. Be sure to
remove the solder from the short point before making
connections.
CAUTION:
THIS PRODUCT UNTILIZES A LASER. USE OF
CONTROLS OR ADJUSTMENTS OR PERFORMANCE OF
PROCEDURES OTHER THAN THOSE SPECIFIED
HEREIN MAY RESULT IN HAZARDOUS RADIATION
EXPOSURE.
4 Handling Precautions for Traverse Deck
4
SA-AK48

5 Precaution of Laser Diode
5
SA-AK48

6 Location of Controls
6
SA-AK48

7 Location of Controls for Remote Control Transmitter
7
SA-AK48

• This section describes procedures for checking the
operation of the major printed circuit boards and
replacing the main components.
• For reassembly after operation checks or replacement,
reverse the respective procedures. Special reassembly
procedures are described only when required.
8.1. Checking for the main P.C.B.
8 Operation Checks and Component Replacement
Procedures
8
SA-AK48

• Check the main P.C.B. as shown below.
8.2. Disassembly for the CD
changer ass’y
(The CD changer unit can be removed until the tray base
ornament would removed.)
8.2.1. Disassembly for the disc tray
ornament
• Follow the (Step 1) -(Step 3) of item 8.1.
9
SA-AK48

8.2.2. Disassembly for the CD changer
unit
• Follow the (Step 1) -(Step 3) of item 8.1.
• Follow the disassembly instruction for the disc tray
ornament of item 8.2.1.
10
SA-AK48

8.3. Checking for the unit
operational condition
(Place the unit horizontally when loading the CD changer unit.)
8.3.1. Initial setting of CD unit
• Follow the (Step 1) -(Step 3) of item 8.1.
• Follow the disassembly instruction for the disc tray
ornament of item 8.2.1.
• Follow the disassembly instruction for the CD changer
unit of item 8.2.2.
11
SA-AK48

8.3.2. Checking for the CD servo P.C.B.
• The initial setting of CD unit must be completed.
(Refer to the initial setting of CD unit in item 8.3.1.)
• Check the CD servo P.C.B. as shown below.
8.3.3. Checking for the FL P.C.B. and
cassette mechanism control P.C.B.
• The initial setting of CD unit must be completed.
(Refer to the initial setting of CD unit in item 8.3.1.)
• Check the FL P.C.B. and cassette mechanism control
P.C.B. as shown below.
12
SA-AK48

8.3.4. Checking for the power supply
P.C.B.
• The initial setting of CD unit must be completed.
(Refer to the initial setting of CD unit in item 8.3.1.)
• Check the power supply P.C.B. as shown below.
8.4. Replacement for the traverse
deck ass’y
• Follow the (Step 1) -(Step 3) of item 8.1.
• Follow the disassembly instruction for the disc tray
ornament of item 8.2.1.
• Follow the disassembly instruction for the CD changer
unit of item 8.2.2.
13
SA-AK48

14
SA-AK48

15
SA-AK48

8.5. Replacement for the disc tray
• Follow the (Step 1) -(Step 3) of item 8.1.
• Follow the disassembly instruction for the disc tray
ornament of item 8.2.1.
• Follow the disassembly instruction for the CD changer
unit of item 8.2.2.
16
SA-AK48

17
SA-AK48

8.6. Disassembly and reassembly
for mechanism base drive unit
• Follow the (Step 1) -(Step 11) of item 8.1.
• Follow the disassembly instruction for the disc tray
ornament of item 8.2.1.
• Follow the disassembly instruction for the CD changer
unit of item 8.2.2.
• Follow the (Step 1) -(Step 9) of item 8.4.
• Follow the (Step 1) -(Step 11) of item 8.5.
18
SA-AK48

19
SA-AK48

20
SA-AK48