Sanyo LA8A

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  • SERVICE MANUAL Colour Television

    Product Code: 13015400

    Original Version

    Chassis Series: LA8-A

    BE2A

    FILE NO.

    Model No. 21TC677U

    Service Ref. No. 21TC677U-00(Argentina)

    Give complete SERVICE REF. NO. for parts order or servicing. It is shown on the rating plate at the cabinet back of the unit.

    This T.V. receiver will not work properly in foreign countries where the television trans-mission system and power source differ from the design specifications. Refer to the speci-fication table.

    SpecificationsPower Source . . . . . . . . . AC220V, 50Hz / 60HzReceiving System . . . . . . PAL (M/M, N/N), NTSC (M/M)Channel Coverage

    Antenna mode VHF: CH02-CH13, UHF: CH14-CH69CATV mode VHF band: CH01-CH13, Mid band: CH14-CH22

    Super band: CH23-CH36, Hyper band: CH37-CH64Ultra band: CH65-CH94 and CH100-CH125Low mid band: CH95-CH99

    Aerial Input Impedance . . 75Input Terminals AV1 (Video): Phono jack 1 AV1 (Audio): Phono jack (R/L) 1 set AV2 (Video): Phono jack 1 AV2 (Audio): Phono jack (R/L) 1 set Output Terminals Video Monitor Output: Phono jack 1 Audio Monitor Output: Phono jack (R/L) 1 Headphone Jack: Mini stereo jack 1Sound Output (RMS) . . . . 3W + 3WSpeakers . . . . . . . . . . . 5cm x 9cm x 2 pcs.Dimensions . . . . . . . . . 597(W) X 464.5(H) X 335(D) mm Weight . . . . . . . . . . . . . approx. 20Kg

    Specifications subject to change without notice.

    JXMRR

    Cabinet type 2 with Noblex control part

    NOBLEX

  • Contents

    -2-

    Safety Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Chassis Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4IC Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8Service Adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-17Purity and Convergence Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Cabinet Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Chassis Electrical Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-26

    Safety Notice

    SAFETY PRECAUTIONS

    1: An isolation transformer should be connected in the power line between the receiver and the AC line when a service is performed on the primary of the converter transformer of the set.

    2: Comply with all caution and safety-related notes provided on the cabinet back, inside the cabinet, on the chassis or the picture tube.

    3: When replacing a chassis in the cabinet, always be certain that all the protective devices are installed properly, such as, control knobs, adjust-ment covers or shields, barriers, isolation resistor-capacitor networks etc.. Before returning any television to the customer, the service techni-cian must be sure that it is completely safe to operate without danger of electrical shock.

    X-RADIATION PRECAUTION

    The primary source of X-RADIATION in television receiver is the picture tube. The picture tube is specially con-structed to limit X-RADIATION emissions. For continued X-RADIATION protection, the replacement tube must be the same type as the original including suffix letter. Excessive high voltage may produce potentially hazard-ous X - RADIATION. To avoid such hazards, the high voltage must be maintained within specified limit. Refer to this service manual, high voltage adjustment for specific high voltage limit. If high voltage exceeds specified limits, take necessary corrective action. Carefully follow the instructions for + B1 volt power supply adjustment, and high voltage check to maintain the high voltage within the specified limits.

    PRODUCT SAFETY NOTICEProduct safety should be considered when a component replacement is made in any area of a receiver. Components indicated by mark in the parts list and the schematic diagram designate components in which safety can be of special significance. It is particularly recommended that only parts designated on the parts list in this manual be used for component replacement designated by mark . No deviations from resistance wattage or voltage ratings may be made for replacement items designated by mark .

  • Chassis Block Diagrams

    -3-

    MAIN SIGNAL PROCESSING CIRCUIT

  • Chassis Block Diagrams

    -4-

    POWER SUPPLY IC601 (STRW6754)

    FUNCTIONAL B

    LOCK D

    IAGRA

    M

  • IC Block Diagrams

    -5-

    IC201 < IF/Video/Chroma/Def./CPU > LA76933

  • IC Block Diagrams

    -6-

    IC001 LA42205

    IC501 LA78141

  • IC Block Diagrams

    -7-

    LA72703 B

    TS

    C D

    eco

    der

    -

    Refe

    rence

    A

    ppri

    cation -

    10

    11

    12

    Sla

    ve A

    ddre

    ss =

    80h (

    1000 000*

    ) :P

    in8=O

    PEN

    /G

    ND

    Sla

    ve A

    ddre

    ss =

    84h (

    1000 010*

    ) :P

    in8=H

    Vcc

    5V

    +

    98

    65

    74

    21

    3

    21

    23

    24

    22

    15

    14

    13

    16

    17

    19

    20

    18

    MA

    TR

    IX

    MO

    DE

    OU

    T

    REG

    ULA

    TO

    R

    ++

    +

    +

    ++

    ++

    +

    4.5

    MB

    PF

    LPF

    SIF

    D

    EM

    OD

    SA

    P B

    PF

    SA

    P D

    EM

    OD

    L-R

    D

    EM

    OD

    ST

    /S

    AP

    S

    W

    LPF

    -6dB

    PIL

    OT

    CA

    NC

    ELL

    ER

    ST

    ER

    EO

    PLL

    PIL

    OT

    DET

    PIL

    OT

    LEV

    EL

    DET

    IIC

    DEC

    OD

    E

    SY

    ST

    EM

    CO

    NT

    RO

    L

    Off

    set

    Cance

    ll

    dbx

    pro

    cess

    or

    SA

    P D

    ET

    4u7

    4u7

    22u

    4u7

    OU

    T(L

    )O

    UT

    (R)

    MO

    DE

    Monitor

    2u2

    1u

    1u

    0.1

    ?1u

    4k7

    MU

    TE

    L+R

    L-R

    /S

    AP

    ST

    SA

    P

    Addre

    ss

    Contr

    ol

    GN

    D

    MU

    TE

    Wide RMS DET

    Spectral DET

    Spectral In

    Offset Cancel

    0.1

    u

    0.1

    u

    4u7

    1u to

    0.3

    3u

    SIF

    S

    IGN

    AL

    from

    T

    uner

    Addre

    ss

    Contr

    ol

    IIC

    DA

    TA

    IIC

    CLO

    CK

    2u2

    22uSpectral RMS

    DET

    100u 0.1

    u47u

    +10u

    +10u

    33n

    33n

    +1u

    +

    560k

    LPF

    IC3401LA72703

  • -8-

    IC Block DiagramsIC3402 R2S15908SP

    R2A15908SP

    INR2

    INR1

    INL1

    INL2

    INL5

    IGOUTL

    VOLINL

    VOLINR

    BASSL1

    INL3

    INL4

    IGOUTR

    BASSR2

    ROUT

    LOUT

    AGND

    SDA

    SCL

    DGND

    BASSL2

    TRER

    VCC

    REFIN

    BASSR1

    INR4

    INR3

    INR5 28

    27

    26

    25

    24

    23

    22

    21

    20

    19

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    18

    17

    11

    12

    Mode selector

    Surround

    REF

    Inputselector

    13

    14

    16

    15

    Ton

    eco

    ntro

    lR

    chB

    ass/

    Tre

    ble

    Volume0~+20dB/2dB step

    Inputselector

    0~-87dB,-

    MCUI/F

    Input gaincontrol

    mute

    mute

    Ton

    eco

    ntro

    lL

    chB

    ass/

    Tre

    ble

    Volume

    0~-87dB,-

    0~+20dB/2dB step

    Mono/Stereo

    TREL

  • -9--9-

    Service Adjustments

    MENU

    S1.11100101 S2.11111000 ADDRESS DATA 01 RFAGC 08

    Item No. Item Data value

    GeneralThis set has an On-screen Service Menu system included in the CPU that allows remote operation for most of the service adjustments.

    2. Service Adjustments: Press the CHANNEL UP or CHANNEL DOWN button on the remote control handset to select the desired service menu item you want to adjust. Use the VOLUME + or - to adjust the data. The + or - button will increase or decrease the data sequentially.

    3. Exit from the Service Menu Press the MENU button to turn off the Service Menu display. The data which is set in the service mode is stored into the memory IC automatically.

    [ Service Mode Display ]

    Service Adjustment-11. Enter the Service Menu While pressing the MENU button on the television, press the Number Key 2 on the remote control unit. The Service Menu now appear.

    IC802 (EEPROM) ReplacementWhen IC802 (EEPROM) is replaced, IC801 (CPU) will automatically write the initial reference data into IC802 for basic TV operation. However, the bus data should be checked and some bus data should be set up before attempting the service adjustments. (See pages 9 ~ 10 for detailed information.)

    JXMRR

    JXMRR

    VOLUME +VOLUME -

    CHANNEL UP

    CHANNEL DOWN

    MENU

    21-BE2E SANYO

    21-BE2F