Panasonic SA-AK250GCP User manual

nAMPLIFIER SECTION
RMS output power
THD 10%, both channels driven
1 kHz 115 W per channel (3 Ω)
Total output power 230 W
nFM/AM TUNER, TERMINALS SECTION
Preset station FM 20 stations
AM 15 stations
Frequency Modulation (FM)
Frequency range
87.50 to 108.00 MHz (50 kHz steps)
Sensitivity 4.0 µV (IHF)
S/N 26 dB 2.2 µV
A
ntenna terminal(s) 75 Ω(unbalanced)
A
mplitude Modulation (AM)
Frequency range 522 to 1629 kHz (9 kHz step)
520 to 1630 kHz (10 kHz step)
Sensitivity
S/N 20 dB (at 999 kHz) 560 µV/m
A
udio performance (Amplifier)
Input Sensitivity/ Input Impedance
A
ux 250 mV, 14.7 kΩ
Music Port input jack
Terminal Stereo, 3.5 mm jack
©2007 Matsushita Electric Industrial Co. Ltd.. All
rights reserved. Unauthorized copying and
distribution is a violation of law.
SA-AK250GCP
Colour
(S)... Silver Type
Sensitivity 100 mV, 4.7 kΩ
Phone jack
Terminal Stereo, 3.5 mm jack
Mic jack
Terminal Mono, 3.5 mm jack
Sensitivity 0.7 mV, 680 Ω
nCASSETTE DECK SECTION
Track system 4 track, 2 channel
Heads
Record/playback Solid permalloy head
Erasure Double gap ferrite head
Motor DC servo motor
Recording system AC bias 100 kHz
Erasing system AC erase 100 kHz
Tape speed 4.8 cm/s
Overall frequency response (+3, -6 dB) at DECK OUT
NORMAL 35 Hz to 14 kHz
S/N ratio 50 dB (A weighted)
Wow and flutter 0.18 % (WRMS)
Fast forward and rewind time Approx. 120 seconds with
C-60 cassette tape
nDISC SECTION
Disc played [8 cm or 12 cm]
CD Stereo System
Notes: This model’s CD mechanism changer unit is CRS1. Please refer to the original Service Manual
(Order No. MD0509368C0) for this mechanism.
Specifications
ORDER NO. MD0704056CE

(1) CD-Audio (CD-DA)
(2) CD-R/RW (CD-DA, MP3* formatted disc)
(3) MP3*
*MPEG-1 Layer 3, MPEG-2 Layer 3
Bit rate
MP3 32 kbps to 320 kbps
Sampling frequency
MP3 32 kHz, 44.1 kHz, 48 kHz
CD-DA 44.1 kHz
Decoding 16 bit linear
Digital filter 8fs
D/A converter MASH (1 bit DAC)
Pick up
Wavelength 780 nm
Beam Source Semiconductor laser
A
udio output (Disc)
Number of channels 2 (Stereo) (FL, FR)
nGENERAL
1 Safety Precautions 4
1.1. General Guidelines 4
1.2. Before Use 4
1.3. Before repair and adjustment 4
1.4. Protection Circuitry 4
1.5. Safety Part Information 5
2 Prevention of Electro Static Discharge (ESD) to
Electrostatically Sensitive (ES) Devices 5
3 Handling Precautions For Traverse Unit 7
4 Precaution of Laser Diode 9
5 About Lead Free Solder (PbF) 10
5.1. Service caution based on legal restrictions 10
6 Accessories 11
7 Operating Procedures 12
7.1. Main Unit Key Buttons Operations 12
7.2. Remote Control Key Buttons Operations 13
8 New Features 14
8.1. Using the Music Port 14
9 Self diagnosis and special mode setting 16
9.1. Service Mode Summary Table 16
9.2. Special Mode Table 1 16
9.3. Reliability Test Mode (CRS1 Mechanism) 19
9.4. Error code Table Display 21
10 Assembling and Disassembling 26
10.1. Caution 26
10.2. Disassembly flow chart 27
10.3. Main Parts Location 28
Power supply
AC 110 to 127/220 to 240 V, 50/60Hz
Power consumption 95 W
Power consumption in standby
mode
0.7 W (Approx.)
Dimensions (W x H x D) 250 x 330 x 323 mm
Mass 7.1 kg
Operating temperature range +5 to +35°C
Operating humidity range 5 to 90% RH (no condensation)
nSYSTEM
SC-AK250 (GCP) Music center: SA-AK250 (GCP)
Speakers: SB-AK250 (PL)
For Information on speaker system, plesae refer to the original
Service Manual (Order No. MD0704055CE) for SB-AK250PL-S.
Notes:
1. Specifications are subject to change without notice. Mass and
dimensions are approximate.
2. Total harmonic distortion is measured by the digital spectrum
analyzer.
10.4. Disassembly of Top Cabinet 29
10.5. Disassembly of CD Changer Unit (CRS1) 29
10.6. Disassembly of Rear Panel 30
10.7. Disassembly of Main P.C.B. 31
10.8. Disassembly of Transformer P.C.B. 31
10.9. Disassembly of Power P.C.B. 32
10.10. Disassembly of Front Panel Unit 32
10.11. Disassembly for Panel P.C.B. 33
10.12. Disassembly of Tact Switch P.C.B. 34
10.13. Disassembly of Deck mechanism unit 34
10.14. Disassembly of Deck P.C.B. 34
10.15. Disassembly of Traverse Unit 35
10.16. Disassembly for Deck Mechanism 36
10.17. Disassembly of Deck Mechanism P.C.B. 39
10.18. Disassembly of cassette lid 40
10.19. Rectification for tape jam problem 40
11 Service Fixture and Tools 42
12 Service Positions 42
12.1. Checking and Repairing of Main P.C.B. 42
12.2. Checking and Repairing of Transformer P.C.B. 43
12.3. Checking and Repairing of Panel, Deck & Deck
Mechanism P.C.B. 43
12.4. Checking and Repairing of Power P.C.B. 44
13 Procedure for Checking Operation of Individual Parts of Deck
Mechanism Unit 45
13.1. Operation Check with Cassette Tape 45
13.2. Operation Check without Cassette Tape 45
CONTENTS
Page Page
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SA-AK250GCP

14 Measurement And Adjustments 47
14.1. Cassette Deck Section 47
15 Voltage and Waveform Chart 49
15.1. CD Servo P.C.B. 49
15.2. Deck P.C.B. & Deck Mechanism P.C.B. 49
15.3. Main P.C.B. 50
15.4. Panel P.C.B. & Transformer P.C.B. 51
15.5. Power P.C.B. 51
15.6. Waveform Chart 52
16 Wiring Connection Diagram 53
17 Block Diagram 55
17.1. CD Servo Diagram 55
17.2. Deck/ Deck Mechanism Diagram 56
17.3. Main Diagram 57
17.4. Panel Diagram 59
17.5. Power Diagram 60
17.6. Transformer Diagram 61
18 Notes Of Schematic Diagram 63
19 Schematic Diagram 65
19.1. (A) CD Servo Circuit 65
19.2. (B) Main Circuit 66
19.3. (C) Panel Circuit 70
19.4. (D) Sub Panel Circuit & (G) Deck Mechanism Circuit 71
19.5. (E) Power Circuit 72
19.6. (F) Deck Circuit 74
19.7. (H) Transformer Circuit 75
20 Printed Circuit Board 77
20.1. (A) CD Servo P.C.B., (F) Deck P.C.B. & (G) Deck
Mechanism P.C.B. 78
20.2. (B) Main P.C.B. 79
20.3. (C) Panel P.C.B. 80
20.4. (D) Sub Panel P.C.B. 81
20.5. (E) Power P.C.B. 82
20.6. (H) Transformer P.C.B. 83
21 Illustration of ICs, Transistors and Diodes 85
22 Terminal Function of IC's 86
22.1. IC7001 (MN6627954MA) Servo Processor,Digital Signal
Processor/Digital filter and D/A Converter 86
22.2. IC7002 (BA5948FPE2) IC 4CH Drive 87
22.3. IC2801 (C2CBYY000482) System Microprocessor 87
23 Exploded Views 89
23.1. Cabinet Parts Location 89
23.2. Deck Mechanism Parts Location (RAA4403-S) 91
23.3. Packaging 92
24 Replacement Parts List 93
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SA-AK250GCP

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, ensure that all the protective devices such as insulation barriers and insulation papers shields are properly
installed.
3. After servicing, check for leakage current checks to prevent 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. Using an ohmmeter measure the resistance value, 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 5.2MΩ.
When the exposed metal does not have a return path to the chassis, the reading must be .
1.1.2. Leakage Current Hot Check (See Figure 1)
1. Plug the AC cord directly into the AC outlet. Do not use an isolation transformer for this check.
2. Connect a 1.5kΩ, 10 watts resistor, in parallel with a 0.15µF capacitor, 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 exposed 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. Should the measurement is out 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.
Fig. 1
1.2. 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 110V or 127V, 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.)
1.3. Before repair and adjustment
Disconnect AC power, discharge power capacitors C5101, C5104, C5171, C5172, C5920, C5940 and C5950 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 110 ~ 127V, 50 Hz in NO SIGNAL mode (at volume min at CD mode) should be ~ 500mA.
Current consumption at AC 220 ~240V, 60 Hz in NO SIGNAL mode (at volume min at CD mode) should be ~ 350mA.
1.4. Protection Circuitry
The protection circuitry may have operated if either of the following conditions are noticed:
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· 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.
1.5. 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
360 RAE0165A-V TRAVERSE UNIT
L5601 G0B9R5K00001 CHOKE COIL
L5602 G0B9R5K00001 CHOKE COIL
S5950 K0ABLB000003 SW VOLTAGE SELECTOR
T5950 G4CYAYY00135 MAIN TRANSFORMER
T5951 G4C2AAJ00005 SUB TRANSFORMER
Z5950 ERZV10V511CS ZENER
RL5950 K6B1AEA00015 POWER RELAY
F1 K5D312BLA015 FUSE
F2 K5D162BLA013 FUSE
FP5920 K5G702A00009 FUSE PROTECTOR
FP5940 K5G702Z00004 FUSE PROTECTOR
FP5950 K5G402A00025 FUSE PROTECTOR
JK5950 K2AA2B000011 JK AC INLET
A2 K2CQ2CA00006 AC CORD
2 Prevention of Electro Static Discharge (ESD) to
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged easily by electricity. Such components commonly are called
Electrostatically Sensitive (ES) Devices. Examples of typical ES devices are integrated circuits and some field-effect transistors and
semiconductor “chip” components. The following techniques should be used to help reduce the incidence of component damage
caused by electro static discharge (ESD).
1. Immediately before handling any semiconductor component or semiconductor-equiped assembly, drain off any ESD on your
body by touching a known earth ground. Alternatively, obtain and wear a commercially available discharging ESD wrist strap,
which should be removed for potential shock reasons prior to applying power to the unit under test.
2. After removing an electrical assembly equiped with ES devices, place the assembly on a conductive surface such as aluminium
foil, to prevent electrostatic charge build up or exposure of the assembly.
3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.
4. Use only an anti-static solder remover device. Some solder removal devices not classified as “anti-static (ESD protected)” can
generate electrical charge to damage ES devices.
5. Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective package until immediately before you are ready to install it. (Most
replacement ES devices are packaged with leads electrically shorted together by conductive foam, aluminium foil or
comparable conductive material).
7. Immediately before removing the protective material from the leads of a replacement ES device, touch the protective material
to the chassis or circuit assembly into which the device will be installed.
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Caution
Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.
8. Minimize body motions when handling unpackaged replacement ES devices. (Otherwise harmless motion such as the brushing
together of your clothes fabric or the lifting of your foot from a carpeted floor can generate static electricity (ESD) sufficient to
damage an ES device).
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SA-AK250GCP

3 Handling Precautions For Traverse Unit
The laser diode in the traverse unit (with optical pickup) may break down due to potential difference caused by the static electricity
of clothes or our human body.
So, be careful of electrostatic breakdown during repair of the traverse unit (with optical pickup).
· Way of handling the traverse unit (with optical pickup)
1. Do not subject the traverse unit (with optical pickup) to static electricity as it is extremely sensitive to electrical shock.
2. To prevent the breakdown of the laser diode, an antistatic shorting pin is inserted into the flexible board (FFC board).
3. Do not to apply excessive stress to the flexible board (FFC board). When removing or connecting the short pin, finish the job
in as short time as possible.
4. Do not turn the variable resistor for laser power adjustment. (It is pre-adjusted during production time)
Grounding for electrostatic breakdown prevention
1. Human body grounding
Use the anti-static 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 traverse unit (with optical pickup) is place, and ground
the sheet.
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 unit (with optical pickup).
Caution when replacing the Traverse Unit
The traverse unit has a short point shorted with solder to protect the laser diode against electrostatics breakdown. Be sure to
remove the solder from the short point before making connections.
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4 Precaution of Laser Diode
Caution :
This product utilizes a laser diode with the unit turned "ON", invisible laser radiation is emitted from the pick up lens.
Wavelength : 780 nm
Maximum output radiation power from pick up : 100 µW/VDE
Laser radiation from pick up unit is safety level, but be sure the followings:
1. Do not disassemble the optical pick up unit, since radiation from exposed laser diode is dangerous.
2. Do not adjust the variable resistor on the pick up unit. It was already adjusted.
3. Do not look at the focus lens using optical instruments.
4. Recommend not to look at pick up lens for a long time.
CAUTION!
THIS PRODUCT UTILIZES A LASER.
USE OF CONTROLS OR ADJUSTMENTS OR PERFORMANCE OF PROCEDURES OTHER THAN THOSE SPECIFIED HEREIN MAY RESULT
IN HAZARDOUS RADIATION EXPOSURE.
nUse of Caution Labels
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SA-AK250GCP

5 About Lead Free Solder (PbF)
5.1. Service caution based on legal restrictions
5.1.1. General description about Lead Free Solder (PbF)
The lead free solder has been used in the mounting process of all electrical components on the printed circuit boards used for this
equipment in considering the globally environmental conservation.
The normal solder is the alloy of tin (Sn) and lead (Pb). On the other hand, the lead free solder is the alloy mainly consists of tin
(Sn), silver (Ag) and Copper (Cu), and the melting point of the lead free solder is higher approx.30 degrees C (86°F) more than that
of the normal solder.
Definition of PCB Lead Free Solder being used
The letter of “PbF” is printed either foil side or components side on the PCB using the lead free solder.
(See right figure)
Service caution for repair work using Lead Free Solder (PbF)
· The lead free solder has to be used when repairing the equipment for which the lead free solder is used.
(Definition: The letter of “PbF” is printed on the PCB using the lead free solder.)
· To put lead free solder, it should be well molten and mixed with the original lead free solder.
· Remove the remaining lead free solder on the PCB cleanly for soldering of the new IC.
· Since the melting point of the lead free solder is higher than that of the normal lead solder, it takes the longer time to melt
the lead free solder.
· Use the soldering iron (more than 70W) equipped with the temperature control after setting the temperature at 350±30
degrees C (662±86°F).
Recommended Lead Free Solder (Service Parts Route.)
· The following 3 types of lead free solder are available through the service parts route.
RFKZ03D01K-----------(0.3mm 100g Reel)
RFKZ06D01K-----------(0.6mm 100g Reel)
RFKZ10D01K-----------(1.0mm 100g Reel)
Note
* Ingredient: Tin (Sn), 96.5%, Silver (Ag) 3.0%, Copper (Cu) 0.5%, Cobalt (Co) / Germanium (Ge) 0.1 to 0.3%
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SA-AK250GCP

6 Accessories
Note: Refer to “Replacement Parts List” (Section 24) for part number.
Remote Control
FM Antenna Wire
AC Cord
AM Loop Antenna
Power Plug Adapter
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SA-AK250GCP

7 Operating Procedures
7.1. Main Unit Key Buttons Operations
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7.2. Remote Control Key Buttons Operations
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8 New Features
8.1. Using the Music Port
This feature enables you to enjoy music from a portable audio equipment.
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With reference to page 15 of the operating instruction manual.
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SA-AK250GCP

9 Self diagnosis and special mode setting
This unit is equipped with functions for checking and inspecting namely: Self-Diagnostic and Test Mode.
9.1. Service Mode Summary Table
The service modes can be activated by pressing various button combination on the main unit and remote control unit. Below is the
summary for the various modes for checking:
Player button Remote control button unit Application Note
[ ] [4], [7] Entering into Doctor Mode Refer to the section, “9.2
Special Mode Table 1 for
more information.
Mode Remote control button unit Application Note
In Doctor Mode [ ], [4]+[7] Display firmware version & EEPROM checksum Refer to the section,
“9.2.1 for more
information.
[4] <Set for cold start when reset start is executed the next time> Refer to the section, “9.2
for more information.
[Muting] Clock Setting Refer to the section, “9.2
for more information.
[0] Tape Eject Test Refer to the section, “9.2
for more information.
[DIMMER] All segment display for the FL Refer to the section, “9.2
for more information.
[DISC] CRS1 Inspection Refer to the section, “9.2
for more information.
[7] Volume 50 Setting check
[8] Volume 41 Setting check
[9] Volume 35 Setting check
[ ] Volume 0 Setting check
[PRESET EQ] EQ Off
[H. Bass] EQ Heavy
[PROGRAM] HIC force MUTE ON/ OFF
[5] CD To Tape recording Inspection
[6] Tape record’s playback
[SLEEP] TPS Inspection
[<] FM Tuning check
[>] Tuner STEREO/ forced MONO
[ ] FM Checking
[ ] AM Checking
9.2. Special Mode Table 1
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9.2.1. EEPROM Checksum (ROM Correction)
Purpose: To check for microprocessor firmware version and EEPROM checksum (ROM correction).
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Below are the procedures for this mode.
Step 1: Enter into Doctor mode (for more information, refer to section 9.2 on the key operation to enter into this mode.
Step 2: Check for firmware version and EEPROM checksum (By pressing STOP button on main unit followed by “4” and “7” on
remote control).
· When entering into DOCTOR MODE, the firmware version and checksum data of EEPROM (if applicable) will appear on FL
display. Below is the information on the EEPROM IC (ROM correction) under 3 possible situations:
1. In the case that the correction point existence data is other than 0 (ie. correction file exists), EEPROM checksum display for
the microprocessor shall be made after calculating checksum by summing up the content of data area from EEPROM IC.
2. In the case when no EEPROM IC is installed. It is display as below (no display of checksum data)
3. In cases that the filename is different even though a EEPROM is installed, or no correction file exists, [NG] shall be displayed
(the correction point existence data is set to 0 at this condition).
Note: Microprocessor firmware refers to version number for microprocessor IC located on PANEL P.C.B.. It is subject to change
which would be updated accordingly. ROM correction checksum refers to the HEX code that is displayed upon key buttons pressed
if an EEPROM is loaded in the unit.
9.3. Reliability Test Mode (CRS1 Mechanism)
Below is the process flow chart of ageing for the CD changer unit. (CRS1)
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