C28xx colorTV Sanyo

  • View
    224

  • Download
    0

Embed Size (px)

Text of C28xx colorTV Sanyo

  • 8/6/2019 C28xx colorTV Sanyo

    1/28

    Service Manual EH1 chassis

    Colour Television Service Manual

    Give complete "SERVICE REF. NO." for parts orderor servicing, it is shown on the rating sheet on thecabinet back of the TV set.

    NoteThis TV receiver will not work properly in foreigncountries where the television transmission systemand power source differ from the design specifications.Refer to the specifications for the design specifications

    ContentsSafety precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2Circuit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-7Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8Service adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-13Component locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14-20Special functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21Waveforms & voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22-27Service parts listsSchematic diagram

    Chassis: EH1-AModel:

    C28ER59 [Europe]C28ER59N [Europe]C28ER59NE [UK/Ireland]

    For further technical information, please refer to thetraining manual EH1 chassis, ref. No. TI520013.

  • 8/6/2019 C28xx colorTV Sanyo

    2/28

    -2-Service Manual EH1 chassis

    SAFETY PRECAUTION

    X-RADIATION PRECAUTION

    The primary source of X-RADIATION in the television receiver is the picture tube. The picture tube is speciallyconstructed to limit X-RADIATION emissions. For continued X-RADIATION protection, the replacement tube mustbe the same type as the original including suffix letter. Excessive high voltage may produce potentially hazardousX-RADIATION. To avoid such hazards, the high voltage must be maintained within specified limit. Refer to thisservice 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 highvoltage adjustment to maintain the high voltage within the specified limits.

    PRODUCT SAFETY NOTICE

    Product 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 whichsafety can be of special significance. It is particularly recommended that only parts designated on the parts list inthis manual be used for component replacement designated by mark /! \ . No deviations from resistance wattageor voltage ratings may be made for replacement items designated by mark /! \ .

    1: An isolation transformer should be connected in thepower line between the receiver and the AC line when

    a service is performed on the primary of the convertertransformer of the set.2: Comply with all caution and safety-related notes

    provided on the cabinet back, inside the cabinet, onthe chassis or the picture tube.

    3: When replacing a chassis in the cabinet, always becertain that all the protective devices are installed

    properly, such as, control knobs, adjustment covers orshields, barriers, isolation resistor-capacitor networksetc.Before returning any television to the customer,the service technician must be sure that it iscompletely safe to operate without danger of electricalshock.

  • 8/6/2019 C28xx colorTV Sanyo

    3/28

    -3-Service Manual EH1 chassis

    This is a diagram for all models and therefore differs slightly from the actual block diagram.

    T u n e r

    I F

    s t a g e

    A 2 s t e r e o

    d e c o

    d e r

    N I C A M

    d e c o

    d e r

    A u d

    i o

    P r o c e s s o r

    3 D

    s u r r o u n d

    p r o c e s s o r

    A u d

    i o

    o u t p u t

    S p e a k e r s

    A V s e

    l e c t o r

    V i d e o

    c h r o m a

    d e f l e c t

    i o n

    d e m o d u l a t o r

    D o u

    b l e

    s c a n

    c o n v e r t e r

    V i d e o

    A p e r t u r e

    C o n

    t r o l

    &

    M a t r i x

    V i d e o

    o u t p u t

    S y s

    t e m

    C o n

    t r o l

    C P U

    m e m o r y

    t e l e t e x t

    d e c o

    d e r

    H / V s y n c .

    d r i v e r

    V e r

    t i c a l

    d r i v e

    &

    w a v e f o r m

    c o n t r o

    l l e r

    V e r

    t i c a l

    o u t p u t

    H o r

    i z o n

    t a l d r i v e

    & o u

    t p u t

    I 2 C b u s

    D / A

    H i g h - v o

    l t a g e

    C R

    T

    V o l u m e

    B a s s

    T r e

    b l e

    B a l a n c e

    M u t e

    A V m o d e

    I 2 C B u s c o n t r o l

    H - C e n

    t r i n g

    V - C e n

    t r i n g

    S I F c a r r

    i e r

    L , R

    L , R

    L , R

    L , R

    L , R

    L , R

    L , R

    A V 4 ( F r o n t

    )

    ( S c a r t )

    A V 1

    A V 4

    A V 3

    A V 2

    Y / C V B S

    C

    Y

    H / V s y n c

    R - Y

    B - Y

    2 Y 2 R - Y

    2 B - Y

    V D

    H D

    V D

    H - D r i v e

    V - d r i v e

    D Y

    R G B I K

    H . V

    R G B

    C o l o u r

    B r i g

    h t n e s s

    C o n

    t r a s

    t

    T i n t

    S h a r p n e s s

    CIRCUIT DESCRIPTION

    Outline

  • 8/6/2019 C28xx colorTV Sanyo

    4/28

    -4-Service Manual EH1 chassis

    This chassis consists of the tuner, IF detector, audiosignal processor, video signal processor, AV selector,double scan converter, vertical deflection, horizontaldeflection and system control circuit that controls all ofthe circuit on this chassis.The RF(radio Frequency) signal input to the tuner fromthe aerial is converted to the IF(Intermediate Frequency)signal in the tuner stage, and then, the composite video(CVBS) signal and the SIF carrier signal are extracted atthe IF detector circuit.The SIF carrier signal is applied to the A2 stereodemodulator circuit and Nicam stereo demodulator circuitrespectively. The A2 stereo demodulator detects the SIFsignal (5.5MHz=Main channel, 5.74MHz=Sub channel)input, and sends out the A2 stereo audio signals outputto the Nicam decoder circuit, and also judges that thereceiving signal is stereo or monaural, and sends out the

    result to the CPU via I 2C bus lines. The Nicam decoderdecodes the SIF signal (5.85MHz components) input andobtains the Nicam stereo audio signals output. This ICalso sends out the status (Nicam or not) to the CPU viathe I 2C bus lines. The obtained A2 stereo or Nicamstereo audio signals are selected by the CPU via the I 2Cbus and supplied to the audio processor circuit as TVaudio signal.

    In the video signal processing stage, video signal outputfrom the IF detector circuit is supplied to the AV selectorcircuit as TV video signal. The AV selector circuit selects

    the output video signal from the input signal of TV video,scart video and front video signal by the CPU via I 2Cbus. The selected video signal is sent to thevideo/chroma demodulator circuit. The video/chromademodulator demodulates the video signal or Y and Csignal and outputs the colour differential signal R-Y, B-Y,Y, H-sync and V-sync signal and supplies them to thedouble scan converter circuit.The double scan converted Y, R-Y and B-Y signals areapplied to the aperture control and RGB matrix circuit.The RGB original colour signal which are obtained at theRGB matrix circuit drive the video output circuit. Thisvideo output circuit also controls the automatic cut-off byfeeding back the AKB(Auto-Kine Bias) pulse on the RGBsignal during the vertical blanking period to the RGBmatrix and video control circuit.The H-sync and V-sync signals are applied to the H/Vsync driver circuit to generate the drive signals for eachoutput circuit. In the vertical signal control circuit, thevertical sawtooth signal applied to the vertical outputcircuit is waveform-shaped to compensate the rasterdistortion.

    On the other hand, the audio processor circuit selects theoutput audio signal from input signals of TV audio, front

    audio and scart audio by the CPU via I 2C bus. Theselected audio signals are sent to the 3D surroundprocessing circuit for adding the 3D surround effects.

    These signals are again input to