PANASONIC SA-AK270EG Service Manual

CD Stereo System

SA-AK270EB SA-AK270EG

Colour (K)... Black Type

ORDER NO. MD0803003CE

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

Specifications

■ AMPLIFIER SECTION

RMS output power stereo mode THD 10%, both channels driven 1 kHz 125 W per channel (3 Ω) Total RMS stereo mode power 250 W

■ FM/AM TUNER, TERMINALS SECTION

Preset station FM 25 stations

AM 15 stations Frequency Modulation (FM) Frequency range

87.50 to 108.00 MHz (50 kHz steps) Antenna terminal(s) 75 Ω (unbalanced) Amplitude Modulation (AM) Frequency range 522to1629kHz(9kHzstep) Music Port (front) jack Sensitivity 100 mV, 4.0 kΩ Terminal Stereo, 3.5 mm jack Headphone jack Terminal Stereo, 3.5 mm jack Output impedance 32 Ω (Max)

■ CASSETTE DECK SECTION

Type 1way 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 Erase 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

■ DISC SECTION

Disc played [8 cm or 12 cm] (1) CD-Audio (CD-DA) (2) CD-R/RW (CD-DA, MP3* formatted disc) (3) MP3* * MPEG-1 Layer 3, MPEG-2 Layer 3 Pick up Wavelength 780 nm Beam Source Semiconductor laser Audio output (Disc) Number of channels 2(FL,FR)

A-AK270EB/SA-AK270E

■ USB SECTION

USB Port USB Standard USB 2.0 full speed Media file format support MP3 (*.mp3) USB device file system FAT 12 FAT 16 FAT 32 USB port power 500 mA (Max)

■ GENERAL

Power supply

Power consumption 65 W Dimensions (W x H x D) 250 x 331 x 342 mm Mass 4.7 kg

AC 230 to 240 V, 50Hz

Operating temperature range 0 to 40°C Operating humidity range 35% to 80% RH (no condensation) Power consumption in standby

mode

■ SYSTEM

SC-AK270 (EB) Music center: SA-AK270 (EB)

Speaker: SB-AK270 (PL)

SC-AK270 (EG) Music center: SA-AK270 (EG)

Speaker: SB-AK270 (PL)

For information on speaker system, please refer to the original Service Manual (Order No. MD0802018CE) for SB-AK270PL-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.

0.4 W

CONTENTS

Page Page

1 Safety Precautions 2 Prevention of Electro Static Discharge (ESD) to

Electrostatically Sensitive (ES) Devices 6 3 Handling Precautions For Traverse Unit 4 Precaution of Laser Diode 5 About Lead Free Solder (PbF) 6 Operation Procedures 7 New Features 8 Self diagnosis and special mode setting 9 Assembling and Disassembling 10 Service Fixture and Tools 11 Service Positions

12 Procedure for Checking Operatio n of Individual Parts of Deck

Mechanism Unit

13 Measurement And Adjustments

14 Voltage Measurement and Waveform Chart

15 Wiring Connect ion Diagram

16 Block Diagram

17 Notes Of Schematic Diagram

18 Schematic Diagram

19 Printed Circuit Board

20 Illustration of ICs, Transistors and Diodes 21 Terminal Function of Integrated Circuits

54 54

22 Exploded Views 23 Replacement Parts List

61 62 64 69 71 79 81

95 103 104 107 111

1 Safety Precautions

SA-AK270EB / SA-AK270EG

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 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

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1.2. Caution for AC Mains Lead

1.3. Before repair and adjustment

Disconnect AC power, discharge AC Capacitors C5700, C5701, C5703, C5704, C5705, C5706 and C5707 through a 10Ω,5W

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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 230V - 240V, 50 Hz in NO SIGNAL mode (volume min at CD mode) should be ~ 500mA.

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 18 RGRX0070C-A REAR PANEL [M] EG 18 RGRX0070C-B REAR PANEL [M] EB 36 RKMX0144-K TOP CABINET [M] 68 REXX0684 PRIMARY WIRE 1 (BLACK) [M] 69 REXX0685 PRIMARY WIRE 2 (RED) [M] 360 RAE0165A-V TRAVERSE ASSEMBLY [M] PCB1 REPX0622J SMPS P.C.B. [M] (RTL) A2 K2CQ2CA00006 AC CORD [M] EG A2 K2CT3CA00004 AC CORD [M] EB DZ5701 ERZV10V511CS ZENER [M] L5001 G0B9R5K00003 LINE FILTER [M] L5002 G0B9R5K00004 LINE FILTER [M] L5701 ELF15N035AN LINE FILTER [M] L5703 ELF22V020A LINE FILTER [M] T2900 G4D1A0000117 TRANSFORMER [M] T5701 ETS42BN1A6AD MAIN SW TRANSFORMER [M] T5751 ETS19AB256AG BACKUP TRANSFORMER [M] PC5701 B3PBA0000402 PHOTO COUPLER [M] PC5702 B3PBA0000402 PHOTO COUPLER [M] PC5720 B3PBA0000402 PHOTO COUPLER [M] PC5799 B3PBA0000402 PHOTO COUPLER [M] F1 K5D502BNA005 FUSE [M] FP2901 K5G4013A0001 FUSE PROTECTOR [M] TH5701 D4CAC8R00002 THERMISTOR [M] TH5860 D4CC11040013 THERMISTOR [M] P5701 K2AA2B000017 AC INLET [M] C5700 F1BAF1020020 1000pF [M] C5701 F0CAF334A087 0.33uF [M] C5703 F0C2H1040001 0.1uF 500V [M] C5704 F1BAF1020020 1000pF [M] C5705 F1BAF1020020 1000pF [M] C5706 F1BAF1020020 1000pF [M] C5707 F1BAF1020020 1000pF [M]

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

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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.

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).

3 Handling Precautions For Traverse Unit

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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.

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4 Precaution of Laser Diode

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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 ungefährlich, 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.

■ Use of caution label

AK270EB / SA-AK270EG

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%

6 Operation Procedures

6.1. Main Unit Key Buttons Operations

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6.2. Remote Control Key Buttons Operations

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7 New Features

7.1. Using the Music Port

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

7.2. Connecting and Playing a USB Mass Storage Class Device

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8 Self diagnosis and special mode setting

This unit is equipped with functions for checking and inspecting namely: Self-Diagnostic and Test Mode.

8.1. 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:

8.2. Service Mode Table 1

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8.3. Service Mode Table 2

8.4. Reliability Test Mode (CRS1 Mechanism)

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Below is the process flow chart of ageing for the Mechanism unit. (CRS1)

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8.5. Error code Table Display

Self-Diagnosis Function (refer Section “8.2 Service Mode Table 1”) provides information on any problems occuring for the unit and its respective components by displaying the error codes. These error code such as U**, H** and F** are stored in memory and held unless it is cleared.

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

SA-AK270EB / SA-AK270EG

8.5.1. Error Code Table (For Deck Mechanism)

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8.5.2. Error Code Table (For CD Changer)

8.5.3. Error Code Table (For Power Supply)

SA-AK270EB / SA-AK270EG

8.5.4. 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.

• 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 [DISC EXCHANGE] to display subsequence error code. It shall repeat after reaching error no. 5. e.g.: [1____IHMS]→ [DISC EXCHANGE] [2____ITOP]→ [DISC EXCHANGE] [3____HOME]→ [DISC EXCHANGE] [4____LOAD]→ [DISX EXCHANGE] [5_____UDD]→ [DISC EXCHANGE]

A-AK270EB/SA-AK270E

3. To clear the error code memory In CRS1 Self-Diagnostic mode, long press [DISC EXCHANGE] key (2s or more)

4. To exit CRS1 Self Diagnostic mode, turn off the set.

9 Assembling and Disassembling

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9.1. Caution

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Special Note:

This model uses a new Mechanism unit (CRS1). In this following section does not contain the necessary disassembly & assembly information for the Mechanism unit (CRS1) except the disassembly & assembly of traverse unit. Kindly refer to the original service manual for the Mechanism 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 “Replacement Parts List” (Section 23), if necessary.

Caution:

After replacing of Mechanism Unit (CRS1), ageing test is necessary. Please confirm operation for Mechanism Unit (CRS1).

Below is the list of disassembly sections

Disassembly of Top Cabinet

•

Disassembly of Mechanism Unit (CRS1)

•

Disassembly of Rear Panel

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Disassembly of Front Panel Unit

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Disassembly of Panel P.C.B., Tact Switch P.C.B. & Remote Sensor P.C.B.

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Disassembly of USB P.C.B.

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Disassembly of Music Port P.C.B.

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Disassembly of CD Lid

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Disassembly of Deck Mechanism Unit

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Disassembly of Deck P.C.B.

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Disassembly of Deck Mechanism

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Disassembly of Deck Mechanism P.C.B.

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Disassembly of Cassette Lid

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Rectification for Tape Jam Problem

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Disassembly of Traverse Unit

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Disassembly of D-Amp P.C.B.

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Replacement of Digital Power Amp IC

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Disassembly of Main P.C.B.

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Replacement for Switch (Q2751)

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Disassembly of SMPS P.C.B.

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Replacement for Switch Regulator IC (IC5701)

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Replacement for Switch Regulator Diode (D5702)

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Replacement for Regulator Diode (D5801)

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Replacement for Regulator Diode (D5802)

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Replacement for Regulator Diode (D5803)

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Disassembly of AC Inlet P.C.B.

•

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

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9.2. 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.

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9.3. Main Components and P.C.B. Location

9.4. Disassembly of Top Cabinet

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Step 1

Remove 3 screws on both sides of the top cabinet.

Step 2

Remove 5 screws at the rear panel.

release the catches.

Step 5

Lift up the top cabinet and remove it in the direction of

arrow.

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Step 3

Lift the sides of top cabinet outwards as arrow shown.

Step 4

Push the top cabinet backwards as arrow shown to

9.5. Disassembly of Mechanism Unit (CRS1)

• Follow the (Step 1) - (Step 5) of Item 9.4

Step 1

Remove 1 screw at rear cover.

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Step 2 Detach the FFC cables at connectors (CN2801 &

CN2805) at Main P.C.B..

Special Note: During reassembling procedure, ensure both the claws and catches are fully catched.

Assembly is secured upon hearing a click sound.

Step 5 Release the tabs at the bottom of the front panel.

Step 3 Release the claws outwards on both sides. Step 4 Release catches at both sides.

Caution: Do not exert strong force when releasing the tabs. Step 6 Shift the front panel unit slightly forward in the direction

of arrows.

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