Panasonic SAAK-750-E, SAAK-750-EB, SAAK-750-EG Service manual

CD Stereo System

SA-AK750E SA-AK750EB SA-AK750EG

Colour

(K)... Black Type

ORDER NO. MD0703026CE

Notes: This model’s CD mechanism changer unit is CRS1. Please refer to the original Service Manual (Order No. MD0509368C0) for this mechanism.

Specifications

n AMPLIFIER SECTION

RMS output power

THD 10%, both channels driven

1 kHz

(Low channel)

110 W per channel (3 Ω)

10 kHz

(High channel)

110 W per channel (3 Ω)

60 Hz

(Subwoofer channel) 220 W per channel (6 Ω)

Total output power 660 W

n FM/AM TUNER, TERMINALS SECTION

Preset station FM 20 stations

AM 15 stations

Frequency Modulation (FM)

Frequency range 87.5 to 108.0 MHz (50 kHz steps)

Sensitivity 4.0 µV (IHF)

S/N 26 dB 2.2 µV

ntenna terminal(s) 75 Ω (unbalanced)

mplitude Modulation (AM)

Frequency range 522 to 1629 kHz (9 kHz steps)

Sensitivity

S/N 20 dB (at 999 kHz) 560 µV/m

Music Port input jack

Terminal Stereo, 3.5 mm jack

Sensitivity 100 mV, 4.7 kΩ

Phone jack

Terminal Stereo, 3.5 mm jack

n CASSETTE 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

n DISC SECTION

Disc played [8 cm or 12 cm]

(1) CD-Audio (CD-DA)

(2) CD-R/RW (CD-DA, MP3* formatted disc)

SA-AK750E / SA-AK750EB / SA-AK750EG

(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

udio output (Disc)

Number of channels 2 (Stereo) (FL,FR)

n USB SECTION

Playable USB Storage Media

1) HDD

2) USB MP3 Player/Digital audio player

3) USB Thumbdrives

Supported audio file format

MP3 bit rate

USB memory port

Maximum current 500 mA

Bit rate

MP3 32 kbps to 320 kbps

Sampling frequency

MP3 32 kHz, 44.1 kHz, 48 kHz

udio output (MP3)

Number of channels 2 channels

Frequency response (MP3) 20 Hz to 20 kHz (0+/-1.0 dB)

S/N Ratio

USB unit out 85 dB

n GENERAL

Power supply

For E/EG only AC 230 V, 50Hz

For EB only AC 230 to 240 V, 50Hz

Power consumption 139 W

Power consumption in standby mode

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)

n SYSTEM

SC-AK750 (E) Music center: SA-AK750 (E)

Speaker: SB-AK750 (P)

Subwoofer: SB-W AK750 (P)

SC-AK750 (EB) Music center: SA-AK750 (EB)

Speaker: SB-AK750 (P)

Subwoofer: SB-W AK750 (P)

SC-AK750 (EG) Music center: SA-AK750 (EG)

Speaker: SB-AK750 (P)

Subwoofer: SB-W AK750 (P)

For information on speaker system, please refer to the original Service Manual (Order No. MD0703011CE) for SB-AK750P/PC-K and (Order No. MD0703012CE) for SB-WAK750P/PC-K.

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.

0.5 W

CONTENTS

Page Page

1 Safety Precautions

1.1. General Guidelines

1.2. Caution for AC Mains Lead

1.3. Before repair and adjustment

1.4. Protection Circuitry

1.5. Safety Part Information

2 Prevention of Electro Static Discharge (ESD) to

Electrostatically Sensitive (ES) Devices

3 Handling Precautions For Traverse Deck

4 Precaution of Laser Diode

5 Warning

5.1. Service caution based on legal restrictions

6 Accessories

7 Operating Procedures

7.1. Main Unit Key Buttons Operations

7.2. Remote Control Key Buttons Operations

8 New Features

8.1. Using the Music Port

8.2. Connecting and Playing a USB Mass Storage Class

Device

9 Self diagnosis and special mode setting

9.1. Service Mode Summary Table

9.2. Special Mode Table 1

9.3. Reliability Test Mode (CRS1 Mechanism)

9.4. Error code Table Display

10 Assembling and Disassembling

SA-AK750E / SA-AK750EB / SA-AK750EG

10.1. Caution 25

10.2. Disassembly flow chart

10.3. Main Parts Location

10.4. Disassembly of Top Cabinet

10.5. Disassembly of CD Changer Unit (CRS1)

10.6. Disassembly of Rear Panel

10.7. Disassembly of Main P.C.B.

10.8. Disassembly of Transformer P.C.B.

10.9. Disassembly of Power P.C.B.

10.10. Disassembly of Front Panel Unit

10.11. Disassembly for Panel P.C.B.

10.12. Disassembly of Tact Switch P.C.B.

10.13. Disassembly of USB P.C.B.

10.14. Disassembly of Deck mechanism unit

10.15. Disassembly of Deck P.C.B.

10.16. Disassembly of Traverse Unit

10.17. Disassembly for Deck Mechanism

10.18. Disassembly of Deck Mechanism P.C.B.

10.19. Disassembly of cassette lid

10.20. Rectification for tape jam problem

11 Service Fixture and Tools

12 Service Positions

12.1. Checking and Repairing of Main P.C.B.

12.2. Checking and Repairing of Transformer P.C.B.

12.3. Checking and Repairing of Panel, Deck & Deck

Mechanism P.C.B.

12.4. Checking and Repairing of Power P.C.B.

13 Procedure for Checking Operation of Individual Parts of Deck

Mechanism Unit

13.1. Operation Check with Cassette Tape

13.2. Operation Check without Cassette Tape

14 Measurement And Adjustments

14.1. Cassette Deck Section

15 Voltage and Waveform Chart

15.1. USB P.C.B.

15.2. CD Servo P.C.B.

15.3. Power P.C.B. & Transformer P.C.B.

15.4. Panel P.C.B.

15.5. Main P.C.B.

15.6. Deck P.C.B.

15.7. Waveform Chart

16 Wiring Connection Diagram

17 Block Diagram

17.1. CD Servo Diagram

17.2. Deck/ Deck Mechanism Diagram

17.3. Main Diagram

17.4. Panel Diagram

17.5. Power Diagram

17.6. USB/ Transformer Diagram

18 Notes Of Schematic Diagram

19 Schematic Diagram

19.1. (A) CD Servo Circuit

19.2. (B) Main Circuit

19.3. (C) Panel Circuit

19.4. (D) Sub Panel Circuit & (G) Deck Mechanism Circuit

19.5. (E) Power Circuit

19.6. (F) Deck Circuit

19.7. (H) Transformer Circuit

19.8. (I) USB Circuit

20 Printed Circuit Board

20.1. (A) CD Servo P.C.B., (F) Deck P.C.B. & (G) Deck

Mechanism P.C.B.

20.2. (B) Main P.C.B.

20.3. (C) Panel P.C.B.

20.4. (D) Sub Panel P.C.B. & (I) USB P.C.B. (Side A & B)

20.5. (E) Power P.C.B.

20.6. (H) Transformer P.C.B.

21 Illustration of ICs, Transistors and Diodes

22 Terminal Function of IC's

22.1. IC7001 (MN6627954MA) Servo Processor,Digital Signal

Processor/Digital filter and D/A Converter

22.2. IC7002 (BA5948FPE2) IC 4CH Drive

22.3. IC2801 (C2CBYY000423) System Microprocessor

23 Exploded Views

23.1. Cabinet Parts Location

23.2. Deck Mechanism Parts Location (RAA4403-S)

23.3. Packaging

24 Replacement Parts List

SA-AK750E / SA-AK750EB / SA-AK750EG

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 expose d 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 1MΩ and 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. Caution for AC Mains Lead

SA-AK750E / SA-AK750EB / SA-AK750EG

1.3. Before repair and adjustment

Disconnect AC power, discharge Power Capacitors C5101, C5104, C5171, C5172, C5920 , C5940 and C5950 through a 10Ω,5W

SA-AK750E / SA-AK750EB / SA-AK750EG

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 consum ption at AC 230 V, 50 Hz in NO SIGNAL mode (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 :

· 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 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

in the Schematic Diagrams & Replacement Parts List. It is essential that these critical parts should

L5601 G0B9R5K00001 CHOKE COIL L5602 G0B9R5K00001 CHOKE COIL L5603 G0B9R5K00001 CHOKE COIL L5604 G0B9R5K00001 CHOKE COIL L5950 ELF15N035AN LINE FILTER T5950 G4CYAYY00143 TRANSFORMER (MAIN) T5951 G4C2AAJ00005 BACK UP TRANSFORMER Z5950 ERZV10V511CS ZENER

RL5950 K6B1AEA00015 POWER RELAY

F1 K5D252BLA013 FUSE FP5920 K5G103A00019 FUSE PROTECTOR FP5940 K5G103A00019 FUSE PROTECTOR FP5950 K5G402A00025 FUSE PROTECTOR JK5950 K2AA2B000011 JK AC INLET

A2 K2CQ2CA00006 AC CORD EG/ E

A2 K2CT3CA00004 AC CORD EB

SA-AK750E / SA-AK750EB / SA-AK750EG

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 handlin g 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 potent ial 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 exposu re 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 sufficie nt 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 installe d.

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).

SA-AK750E / SA-AK750EB / SA-AK750EG

3 Handling Precautions For Traverse Deck

The laser diode in the traverse deck (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 deck (optical pickup).

· Way of handling the traverse deck (optical pickup)

1. Do not subject the traverse deck (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 deck (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 deck (optical pickup).

Caution when replacing the Traverse Deck

The traverse deck 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.

SA-AK750E / SA-AK750EB / SA-AK750EG

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.

ACHTUNG :

Dieses Produkt enthält eine Laserdiode. Im eingeschalteten Zustand wird unsichtbare Laserstrahlung von der Lasereinheit abgestrahlt. Wellenlänge : 780nm Maximale Strahlungsleistung der Lasereinheit :100 µW/VDE Die Strahlung an der Lasereinheit ist ungefä hrlich, wenn folgende Punkte beachtet werden:

1. Die Lasereinheit nicht zerlegen, da die Strahlung an der freigelegten Laserdiode gefährlich ist.

2. Den werkseitig justierten Einstellregler der Lasereinhit nicht verstellen.

3. Nicht mit optischen Instrumenten in die Fokussierlinse blicken.

4. Nicht über längere Zeit in die Fokussierlinse blicken.

ADVARSEL: I dette a apparat anvendes laser.

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.

n Use of caution label

SA-AK750E / SA-AK750EB / SA-AK750EG

5 Warning

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%

SA-AK750E / SA-AK750EB / SA-AK750EG

6 Accessories

Remote Control

FM Antenna Wire

AC Cord (For E/EG only)

AC Cord (For EB

only)

AM Loop Antenna

7 Operating Procedures

7.1. Main Unit Key Buttons Operations

SA-AK750E / SA-AK750EB / SA-AK750EG

7.2. Remote Control Key Buttons Operations

SA-AK750E / SA-AK750EB / SA-AK750EG

8 New Features

8.1. Using the Music Port

This feature enables you to enjoy music from a portable audio equipment.

SA-AK750E / SA-AK750EB / SA-AK750EG

With reference to page 15 of the operating instruction manual.

SA-AK750E / SA-AK750EB / SA-AK750EG

8.2. Connecting and Playing a USB Mass Storage Class Device

With reference to page 16 of the operating instruction manual.

SA-AK750E / SA-AK750EB / SA-AK750EG

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] Enter Doctor Mode Refer to the section, “9.2

Mode Remote control button unit Application Note

In Doctor Mode Main unit [ ],

[4]+[7]

[4] Set for cold start when reset start is executed the next time Refer to the section, “9.2

[Muting] Clock Setting Refer to the section, “9.2

[0] Tape Eject Test Refer to the section, “9.2

[DIMMER] All segment display for the FL Refer to the section, “9.2

[DISC] CRS1 Inspection Refer to the section, “9.2

[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 OK/ NG (98.1 MHz) [ ] AM OK/ NG (1000 KHz)

Display EEPROM Information Refer to the section,

Special Mode Table 1 for more information.

“9.2.1 for more information.

for more information.

9.2. Special Mode Table 1

Item FL Display Key Operation

Mode Name Description Front Key

Self -Diagnostic

Mode

To enter into self diagnostic checking for main unit.

1. Select [

2. Press and hold [

To exit, press main unit or remote control.

] for TAPE mode (Ensure no tape is inserted).

]button for 3

seconds follow by [

button on

SA-AK750E / SA-AK750EB / SA-AK750EG

Item FL Display Key Operation

Mode Name Description Front Key

Doctor Mode To enter into Doctor

(Display 1) Mode for checking of various items and displaying checksum and software version. FL Display sequence: Display 1 → 2

(Display 2)

1. All segments will light up for 1 second.

2. The Check Sum of EEPROM and firmware version will be display.

* ROM correction ** Firmware version No:

CD Test Mode To enter into checking the

reliability of changer unit.

CD Auto

Adjustment

To check the CD auto adjustment result for FLOCK, TLOCK and CLVS. FLOCK: Focus Lock TLOCK: Traverse Lock CLVS: Constant Linear Velocity Speed

In any mode:

1. Press [

] button on main unit

follow by [4] and [7] on remote control.

To exit, press [ENTER] button on remote control or

button on main

unit.

In any mode:

1. Select [

2. Press and hold [ seconds follow by [

To exit, press

] for CD mode.

] button for 3

button on

main unit or remote control. In CD Test Mode:

1. Press [0] button on the remote control.

To exit, press

button on

main unit or remote control.

CD Changer

Reliability Test

(CRS1)

To determine the reliability of CD Changer Unit. (For more information, refer to section 9.3)

SRVC_TRV To unlock the traverse

unit for service. FL Display sequence: Display 1 → 2

Open/ Close Test To check the function

operation of changer unit. (For more information, refer to 9.3)

(Display 1)

(Display 2)

In Self-Diagnostic Mode:

1. Select [

2. Press [

To exit, press

] for CD mode.

] button.

button on main unit. (The tray will return to PLAY position and then power off)

In Tape mode:

1. With no cassette tape inserted,

2. Press [

],[ ] button

on main unit.

3. Press [SINGLE CHANGE] on main unit.

To exit, press [

] button on

main unit.

In doctor mode:

1. Press [DISC] on remote control.

To exit, press [ENTER] button on remote control or

button on main

unit.

Item FL Display Key Operation

Mode Name Description Front Key

Tape Eject Test To check on the tape

eject function (For deck 1/2)

In doctor mode:

1. Press [0] button on remote control.

SA-AK750E / SA-AK750EB / SA-AK750EG

FL Display Test To check the FL

Cold Start To activate cold start

Clock Setting

Check

segments display (All segments will light up and LED will blink at 0.5 second interval)

upon next AC power up.

To indicate that a clock time was set properly

In doctor mode:

1. Press [DIMMER] button on remote control.

In doctor mode:

1. Press [4] button on remote control.

To exit, press [ENTER] button on remote control or unit.

In doctor mode:

1. Press [MUTING] button on remote control.

button on main

9.2.1. EEPROM Checksum (ROM Correction)

Purpose: To check for microprocessor firmware version and EEPROM checksum (ROM correction).

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: (By pressing STOP button on main unit followed by “4” and “7” on remote control) Check for firmware version and EEPRO M checksum.

· W hen 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 EEPRO M IC.

2. In the case when no EEPRO M 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).

SA-AK750E / SA-AK750EB / SA-AK750EG

Note: Microprocessor firmware refers to version number for microprocessor IC located on PANEL P.C.B.. It is subject to change

which would be update d 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)

SA-AK750E / SA-AK750EB / SA-AK750EG

9.4. Error code Table Display

Self-Diagnosis Function (refer Section 9.2) provides information on any problems occuring for the unit and its respective components by display ing the error codes. These error code such as U**, H** and F** are stored in memory and held unless it is cleared.

SA-AK750E / SA-AK750EB / SA-AK750EG

The error code is automatically display after entering into self-diagnostic mode.

9.4.1. Error Code Table for Deck Mechanism

Error Code Diagnosis Contents Description of error Automatic FL Display Remarks

H01 Mode SW, plunger

and capstan motor abnormal

H02 Rec INH SW

abnormal

H03 HALF SW abnormal For deck mechanism unit.

Normal operation during mecha transition, MODE SW abnormal is memorized. The content of abnormality can be confirmed in the abnormal detection mode explained in the later section.

The content of abnormality can be confirmed in the abnormal detection mode explained in the later section.

For deck mechanism unit. Press [ next error.

Press [ next error.

] on main unit for

F01 Reel pulse abnormal For deck mechanism unit.

Press [ next error.

] on main unit for

9.4.2. Error Code Table For CD Changer Block

Error Code Diagnosis Contents Description of error Automatic FL Display Remarks

F15 RESET SW

abnormal

F26 Transmission error

between CD Servo LSI IC and microprocessor IC

IHMS Cam gear

abnormality

ICSL Cam gear/gear units

abnormal

ISTK Drive rack/gear

assembly abnormal

REST SW: ON is not detected within the specified time.

When set to CD mode, the sense signal does not turn “Low”, a fail safe time after system command transmission is sent.

Cam gear does not rotate to “HOME” position.

Cam gear does not rotate to “PLAY” driving position and hence does not drive playing tray to “STOCK” position.

The tray drive rack does not move to “STOCK” position. (Tray does not move to “STOCK” position)

For CD unit (For Traverse). Press [ next error.

For CD changer unit (CRS1). Press [SINGLE CHANGE] on main unit for next error.

] on main unit for

IPLY Drive rack/gear

assembly abnormal

ITOP UD assembly UD Rack does not move to

IUDS UD assembly After TOP SW is detected,

The tray drive rack does not move to “PLAY” position. (Tray does not move to “PLAY” position)

front direction. This lead to UD base not raise to top position.

UD rack does not move into tray 1 position.

For CD changer unit (CRS1). Press [SINGLE CHANGE] on main unit for next error.

Error Code Diagnosis Contents Description of error Automatic FL Display Remarks

HOME Cam gear/gear

assembly abnormal

LOAD Tray drive assembly

abnormal

Cam gear does not move to “HOME” position under following conditions

1. After tray is load to “PLAY” position.

2. After tray is unload to “STOCK” position.

Tray unit does not move from “STOCK” to “PLAY” position

For CD changer unit (CRS1). Press [SINGLE CHANGE] on main unit for next error.

SA-AK750E / SA-AK750EB / SA-AK750EG

UNLD Tray drive assembly

abnormal

PDRV Cam gear/gear

assembly abnormal

UDU UD base asssembly

abnormal

UDD UD base asssembly

abnormal

F1NG Fail - safe mode. (For

open/close tray unit(s))

F2NG Fail - safe mode. (For

open/close tray unit(s))

SRVC_TRV To unlock the

traverse unit for service

RSET Cam gear jam/close

sensor faulty

Tray unit does not move from “PLAY” to “STOCK” position

Cam gear does not move from “HOME” to “PLAY” drive position.

UD Base assembly does not move upwards from tray 5 to tray 2

UD Base assembly does not move downwards from tray 1 to tray 5.

When the tray open operation is performed, it fails to open. It will automatically close all trays after the time-out by the microprocessor. During this time when it fails, the error code will appear.

When the tray close operation is performed, it fails to close. It will automatically open all trays after the time-out by the microprocessor. During this time when it fails, the error code will appear.

1. All trays set to “STOCK” position

2. Mechanism set to tray 5

3. Cam gear set to “HOME” position

During tray re-open, the cam gear will rotate in the opposite direction to reset the cam gearposition. When it fails, the error code will appear.

For CD changer unit (CRS1). Press [SINGLE CHANGE] on main unit for next error.

9.4.3. Error Code Table For Power Supply

Error Code Diagnosis Contents Description of error Automatic FL Display Remarks

F61 Power Amp IC output

abnormal

Upon power on, PCONT=HIGH, DCDET=L after checking LSI.

For power. Press [ next error.

] on main unit for

9.4.4. CRS1 Error Code display

CRS1 Error Code display

1. The errors that occured in CRS1 Mechanism can be recalled and displayed, in the order of the occurence under self-diagnostic for procedures to enter this mode.

SA-AK750E / SA-AK750EB / SA-AK750EG

· Only the first 5 errors will be memorized (in backup memory). The subsequence error shall be ignored and not memorize.

For system with EEPROM as memory backup,memory space in EEPROM is neccesary.

2. To display all error code memorized

In CRS1 Self-Diagnostic mode, press [SINGLE CHANGE] to display subsequence error code.

It shall repeat after reaching error no. 5.

e.g.:

[1____IHMS]→ [SINGLE CHANGE]

[2____ITOP]→ [SINGLE CHANGE]

[3____HOME]→ [SINGLE CHANGE]

[4____LOAD]→ [SINGLE CHANGE]

[5_____UDD]→ [SINGLE CHANGE]

3. To clear the error code memory

In CRS1 Self-Diagnostic mode, long press [SINGLE CHANGE] key (2s or more)

SA-AK750E / SA-AK750EB / SA-AK750EG

10 Assembling and Disassembling

10.1. Caution

Special Note:

This model uses a new CD changer unit CRS1. In this following section does not contain the necessary disassembly & assembly information for the CD changer unit (CRS1) except the disasembly & assembly of traverse unit. Kindly refer to the original service manua l for the CD changer unit. (Order No. MD0509368C0).

“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 respective procedures. Special reassembly procedures are described only when required.

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

4. Refer to the Parts No. on the page of “Parts Location and Replacement Parts List” (Section 24), if necessary.

Caution:

After replacing of CD Changer Unit, ageing test is necessary. Please confirm operation for CD Changer Unit.

Below is the list of disassembly sections

· Disasse mbly of Top Cabinet

· Disasse mbly of Rear Panel

· Disasse mbly of CD Changer Unit (CRS1)

· Disasse mbly of Main P.C.B.

· Disasse mbly of Transformer P.C.B.

· Disasse mbly of Power P.C.B.

· Disasse mbly of Front Panel Unit

· Disasse mbly of Panel P.C.B.

· Disasse mbly of USB P.C.B.

· Disasse mbly of Tact Switch P.C.B.

· Disasse mbly of Deck Mechanism Unit

· Disasse mbly for Deck P.C.B.

· Disasse mbly of Traverse Unit

· Disasse mbly of Deck Mechanism

· Disasse mbly of Deck Mechanism P.C.B.

· Disasse mbly of cassette lid

· Rectification for tape jam problem

Below shown is part no. of different screws types used:

SA-AK750E / SA-AK750EB / SA-AK750EG

10.2. 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 as below.

10.3. Main Parts Location

SA-AK750E / SA-AK750EB / SA-AK750EG

10.4. Disassembly of Top Cabinet

Step 1 Remove 3 screws on both sides on top cabinet.

Step 2 Remove 5 screws at the rear.

Step 3 Lift the sides of top cabine t outwards.

Step 4 Push the top cabinet backwards to release catches.

Step 5 Remove top cabine t.

10.5. Disassembly of CD Changer Unit (CRS1)

· Follow the (Step 1) - (Step 5) of Item 10.4

Step 1 Remove 1 screw at rear panel.

Step 2 Detach the FFC cables (CN2801 & CN2805) at Main

P.C.B..

Step 3 Release the claws outwards on both ends.

SA-AK750E / SA-AK750EB / SA-AK750EG

Step 4 Lift the CD changer unit upwards to remove it.

· Disasse mbly of Mecha Chassis

Step 5 Remove 2 screws.

Step 6 Remove the Mecha Chassis.

Note:

For disassembly & assembly of traverse unit, please refer to section 10.16 of this service manual.Please refer to original Service Manual for the Disassembly and Assembly of the CD Changer Unit (CRS1).

10.6. Disassembly of Rear Panel

· Follow the (Step 1) - (Step 5) of Item 10.4

Step 1 Remove 6 screws.

SA-AK750E / SA-AK750EB / SA-AK750EG

Step 2 Detach cable CN2810 at Main P.C.B..

Step 3 Detach FFC cables (CN2801 & CN2805) at Main

P.C.B..

Step 4 Remove rear panel.

+ 76 hidden pages