Service Manuals, User Guides, Schematic Diagrams or docs for : Daewoo Proj TV SJ-112 chassis SJ112

<< Back | Home

Most service manuals and schematics are PDF files, so You will need Adobre Acrobat Reader to view : Acrobat Download Some of the files are DjVu format. Readers and resources available here : DjVu Resources
For the compressed files, most common are zip and rar. Please, extract files with Your favorite compression software ( WinZip, WinRAR ... ) before viewing. If a document has multiple parts, You should download all, before extracting.
Good luck. Repair on Your own risk. Make sure You know what You are doing.

Image preview - the first page of the document

>> Download SJ112 documenatation <<

Text preview - extract from the document
                                              S/M No. :DSJ112FEFO

Service Manual

  : In this Manual, some parts can be changed for improving. their
    performance without notice in the parts list. So, if you need the
    latest parts information, please refer to PPL(Parts Price List)in
    Service Information Center(

 http : //                             Feb. 2004
1. Safety Instruction                      3

2. Product Specification                   4

3. Remote Control                          5

4. Adjusting Method                        6

5. Explanation for circuit operation       12

6. Trouble Shooting                        34

7. Service Part list                       43

8. Schematic Diagram
  1) Block Diagram                         76
  2) Power                                 77
  3) Rear IO                               78
  4) AV main                               79
  5) deflection                            80
  6) Convergence Amp & Sound Amp           81
  7) Convergence Module                    82
  8) CRT Amp                               83
  9) Control & side                        84

  1) Main PCB                              85
  2) Power PCB                             86
  3) AMP PCB                               87
  4) CRT PCB                               88
  5) DEF PCB                               89
  6) UNION-1 PCB(CONTROL, SIDE)            90

  1) DSJ-4710                              92
  2) DSJ-4720                              93
  3) DSJ-5510                              94
  4) DSJ-5520                              95

1. Safety Instruction
1. When all services are carried out, every item required in this manual needs to be followed
   and the services should be performed by A/S man.

2. The following general items should be performed before staring the services.
  1) Unplug the power.
  2) Uncover the cabinet.
  3) To prevent a danger of shock, touch a terminal of plug on the chassis ground and discharge
     a remaining voltage.
  4) Check if all parts are in the proper places, omitted or burned.
  5) Check the soldering state of all parts, if a clad copper is loose or peeled off and if there is a
     short between clad coppers.
  6) When all the articles mentioned above are normal, plug the power and refer to "Fault
     diagnosis according to cause and symptom" of this manual for service according to screen

3. Pay attention to a basic wiring and check a damaged part if a disconnected circuit is found
   and replace it with a new one.

4. The equal rated parts should be used depending on the parts list of this manual when a part
   needs to be replaced. Because some electronic parts and appliances have safety-related
   features, an electric shock, file or X-RAY radiation can be caused if no equal rated parts are

5. When a part needs to be replaced and soldered on PCB, the part should be inserted in the
   right position and not contact with even a terminal of other part.
   Especially, a high voltage resistance should be inserted with 10mm away from the PCB.

6. Since approx. 30KV high voltage is applied to the Braun tube in operating the TV set, a little
   X-RAY can be radiated. If the voltage is too high, harmful X-RAY can result in a danger.
   Therefore, A/S man with sufficient knowledge about high voltage needs to perform the
   service. Especially, be sure to discharge the anode of the Braun tube on the chassis ground
   of TV set before starting the repair.

7. Examine the followings before finishing the service.
  1) Check if all protecting components have been assembled.
  2) Keep the lead line away from high voltage or high temperature parts and check if all wires
     have been connected.
  3) Check a leakage current to protect a user from a shock.
     Observances for safe service

8. How to check a leakage current
   1) Plug the power directly.
   2) After connecting 1.5V 10W resistance and 0.15uF condenser in a row, link one with an
      exposed metal part of TV set and earth the other (proper earth place such as water pipe).

9. A couple persons or more should perform the repair.
    When a back cover needs to be separated, pull it out about half and remove the power cord
    before complete uncovering.

10. Remove the anode cable which is fixed at HVG in separating the anode cable from HVG or
    replacing CRT or HVG. Because a high voltage charged in the anode isn't discharged
    completely even though the AC power cord is removed, the high voltage can be sent to TV
    set via the power cord and cause its damage.
     Therefore, be sure to observe the following method in replacing a high voltage cable.
  1) How to remove a high voltage cable
     a. Make a discharger to discharge a high voltage.
     b. Remove the power cord and wait for 30 sec.
     c. Remove the anode cable after discharging as the method mentioned below.
  2) How to produce
     a. Solder MW resistance and clip lead.
     b. Place the soldered part on a driver to tap.
  3) How to discharge
     a. Connect the clip with CRT NET GND.
     b. Pull upward the anode cable slightly, giving a proper force to both nippers of the high
        voltage plug locked in HVG. Then, the HVG is removed from the high voltage cable. Be
        careful not to destroying the HVG plug socket which connects the high voltage plugs by
        giving an excessive force to the nippers in the course.
     c. To discharge a high voltage, contact the discharger with a peeled wire at the end of the
        anode cable which is removed from HVG.
     d. When separating the high voltage plug from the high voltage cable, put both tips of a
        pincette in the plug and pull the plug to the end of the high voltage cable.

2. Specifications

           Input voltage            AC 220V, 60Hz
           Power consumption        230watts
           Dimensions (W x H x D)   1278 x 1351.7 x 586mm (5510)
                                    1278 x 1351.7 x 591mm (5520)
General                             1110 x 1210 x 532.5mm (4710)
                                    1110 x 1210 x 529.5mm (4720)
           Weight                   77.9Kg(55"), 66.5Kg(47")
           Antenna input            One 75 ohm external input terminal
                                    for UHF/VHF/Cable
           Screen size              139cm(55"),119cm(47"), 16:9 Aspect Ratio
           Scanning type            DTV : 1080I @ 33.75KHz
Image                               NTSC/DVD: 480p @ 31.5KHz
                                               1080I @ 33.75KHz
           CRT size                 7"
           Sound system             3D Stereophonic sound
           NTSC voice               Stereo, Sound multiplex
           Voice output             15W/ch (Main L/R)
           Antenna input            2EA
           NTSC AV input            2pairs (S-Video/Video/L/R)
External   NTSC AV monitor output   1pair(Video/L/R)
Input/     Component input          2pair(Y/Pb/Pr)
Output     Right
           NTSC AV input            1pairs(S-Video/Video/L/R)

3. Specifications of remote control

                               DISPLAY               Power


                                                     Channel number (0-9)
                                                     Use to select channel directly 0~9

                                        100          Prev
          Use it when selecting a channel            It returns to previous channel.
                      number of over 100

        Use it to make picture adjustment,
        screen format, sound adjustment,
               input selection, and utilities.       TV -> Component 1 -> Component 2 -> TV

                Use this function to make
                     video input selection.          CH
     It changes in the following sequence
             TV -> VIDEO1 -> 2 -> 3 -> TV

                       Dolby Virtual

          CHANNEL ADD/ERASE                          Sound Mode
        This feature either memorizes the            This feature allows you to choose the mode ,
      current channel or erases a channel            Each time the button is pressed, it rotates from
           that has previously memorized.            Normal -> Music -> Movie -> News -> User.
                         Sleep Timer                 Bilingual Broadcasting
    This feature is used to set up the time          This feature allows you to select the
                      of automatic turn off.         language while broadcasting.

                       Screen Size                   VCR Function
    This feature converts the screen size by         REW, PLAY, FF, STOP, REC, PAUSE
    changing its aspect ratio. Each time you         Caption
    press the button, it will be changed from        This feature allows you to choose the
       16:9 -> 4:3 -> Panorama -> ZOOM1              caption.
                                    ->ZOOM2          Each time the button is pressed it rotates
                                                     from CC1 -> CC2 -> CC3 -> CC4 -> Off
                      Auto Picture                   ANT
         Standard -> Cinema -> Dynamic -> User
                             TV/Video                STILL
                              Position               SWAP

 4. Adjusting Method

Adjustment of temporary ITC

Step 1. Temporary fixation of DY

1) Insert DY in R, G, B CRT and tighten the screws properly with DY pushed upward to the end
   (Refer to Figure 1)
2) Adjust the slant and position of DY so that the rectangle projections of DY are shown in front
   of the set.

                          DY rectangle           GENTERING VM COIL
                          projection             MAGNET

                              (Figure 1. Front part of CRT assembly)

Step 2. Fixation of VM coil

1) Tighten the screw completely with R, G, B, VM coil pushed upward to the end (Refer to
   Figure 1)

Applied chassis and model:SJ-111, 112/DSJ-5510(20),DSJ-4710(20)

                                                                             Adjusting Method

Completion of control

- All adjustments need to be performed after heat-run for 30 min or more.
- Heat-run is executed in the state of non-signal noise.
- If a retrace line appears on the screen during heat-run, rotate the screen VR left and carry out
  heat-run when it disappears.
- Note) If stop image is kept over 10 min, a fluorescent material of CRT can be damaged.

Step 1. Control of screen voltage

1) Select `Video 1' without a signal.
2) After turning the screen VR of focus pack right, slowly rotate it left when a retrace line
   appears and fix it when the line disappears completely.
3) Control Red VR, Green VR and Blue VR in the order.
4) Fix the VR by lock paint after the control is completed.
   Note) This control should be performed in a darkroom.



               [Figure 2. Exterior view of focus-pack]

Step 2. Control of P-Lens focus

 1) Receive RETMA pattern.
 2) Loose the fixing nut of lens.
 3) Rotate the fixing nut of lens left and then right slowly. Fix the optimum focus position by
    repeating this method.
  Note 1) Control the focus on the basis of 6cm by 6cm (intra-office signal 8CH, No.3) at the
          left bottom of the screen.
  Note 2) Perform the focus readjustment or correction if the entire screen isn't focused even
          after the completion of focus control.

Applied chassis and model:SJ-111, 112/DSJ-5510(20),DSJ-4710(20)

 Adjusting Method

 4) When the focus control is finished, apply a silicon bond between inside and outside
    diameter, paying attention so that the lens isn't moved.
 5) Project R, G, B signal only by one signal, using a lens cover and control G, R and B in the
  Note) This control should be performed in a darkroom. Especially, be careful not to touch the
        lens with a hand.

Step 3. Focus control

 1) Receive RETMA pattern.
 2) Rotate the focus-pack of focus VR right and left to fix the optimum focus.
  Note 1) Control the focus on the basis of 6cm by 6cm (intra-office signal 8CH, No.3) at the
           left bottom of the screen.
  Note 2) Perform the focus readjustment or correction if the entire screen isn't focused even
           after the completion of focus control.
 3) Project R, G, B signal only by one color, using a lens cover and control G, R and B in the

Step 4. Control of G-CRT 2-pole, 4-pole magnet

 1) Receive DOT pattern.
 2) Have only a green screen appear, using a lens cover.
 3) Adjust the core to be located in the center of DOT, using a 4-pole magnet.
 4) Adjust the DOT to be circular, using a 2-pole magnet.
 5) Tighten the fixing part so that the magnet can't move after finishing the adjustment.
  Note 1) This control should be performed in a darkroom.
  Note 2) Perform the focus readjustment or correction if the entire screen isn't focused even
          after the completion of focus control.

Applied chassis and model:SJ-111, 112/DSJ-5510(20),DSJ-4710(20)

                                                                            Adjusting Method

Step 5. Control of deflection yoke and tilt

 1) Receive CROSS-HATCH pattern.
 2) Rotating a loose DY left and right, control it so that the horizon of R, G, and B can be
    projected on to the screen correctly in the form of horizon. (Refer to the center point of
    Front -Mask)
 3)After adjusting the R, G, B, FY, fix the DY with a lever not to turn.

Step 6. Control of raster position

 1) Receive CROSS-HATCH pattern.
 2) Adjusting the centering magnet attached to the DY, locate the center of green image at the
    center of the screen (Refer to Figure 1).
 3) Adjusting the centering magnet of R and B, locate R left and B right on the basis of G in the
 4) Fit the horizon in the center of R and B to the horizon of G.
 5) In the center of screen, locate the vertical line of R approx. 20 to 30mm to the left on the
    basis of G and the vertical line of G approx.20 to 30mm to the right (Refer to Figure 4).

                                 Figure 4. Control of R, G, B raster

Step 7. Control of convergence

a. Control of 480i convergence
 1) Input the signal of auto alignment system in a component terminal.
    (Select one between component 1 and 2.)

Applied chassis and model:SJ-111, 112/DSJ-5510(20),DSJ-4710(20)

 Adjusting Method

 2) Connect I2C line of the auto alignment system with housing (P503) at the top of a
    convergence board.
 3) Select CONV.EXE in the auto alignment system program and press ENTER.
 4) Control the user convergence with a remote control after the control is finished.

b. Control of 1080i convergence
 1) Repeat the above 1) to 4) for 1080i mode.

Step 8. Control of white balance

 1) Connect a control pattern (intra-office signal cable broadcasting 32 CH) with external input 3.
 2) Select the screen mode as standard.
 3) Locate the sensor of 3298 system at the center of High/Low Beam.
 4) Execute the projection program of control PC.
 5) When OSD of `OK' appears on the monitor of control PC, the control is completed.

  Measuring unit: Multimedia Display Tester 3298(YOKOGAYA)
  Measuring signal: White -Balance Control Pattern (Intra-office signal cable broadcasting
  Coordinates setup:x=0.275 0.005 / y=0.275 0.005
  Initial data (S8)

 R CUT : 61 (RED BIAS)

Applied chassis and model:SJ-111, 112/DSJ-5510(20),DSJ-4710(20)

                                                                           Adjusting Method

Step 9.

Control of 480p color accord

 1) Receive Cross-Hatch 480p signal by using HD signal output instrument.
 2) Press the S7 key of service remote control to enter the 480p color accord control mode.
 3) Change RHLIN to control RED color accord.
 4) Change BHLIN to control BLUE color accord.

  Measuring unit:VG-858(ASTRO)
  Initial data (S7)
  RH LIN : -53
  BH LIN : +127

Step 10.

Control of sub brightness

- Press the S9 key to enter the Sub Brightness control mode.
- Screen mode: Standard
  1) Receive RETMA pattern (intra-office signal cable broadcasting 96 CH)
  2) Press the S9 key.
  3) Control the Sub Brightness so that 18% gradation can be identified in the contrast chart of
     gradation pattern.

Applied chassis and model:SJ-111, 112/DSJ-5510(20),DSJ-4710(20)

 5. Explanation for circuit operation

                                       < Contents >

1. Specifications and Features
  1-1 Specifications of product
  1-2 Features of product

2. Power
  2-1 Outline
  2-2 Block diagram
  2-3 Composition of power supply
  2-4 Explanation for power supply operation

3. Deflection
  3-1 Outline
  3-2 Block diagram
  3-3 Composition of deflection part
  3-4 Explanation for operation

4. Video signal processing
  4-1 Block diagram
  4-2 Video processor

5. Sound
  5-1 Switching part
  5-2 Sound processing

6. Convergence
  6-1 Outline
  6-2 Block diagram
  6-3 Composition


                                                               Explanation for circuit operation

1. Specification/Feature

1-1. Specification of prodict

           Input voltage                   AC 220V, 60Hz
           Power consumption               230watts
           Dimensions (W x H x D)          1278 x 1351.7 x 586mm (5510)
                                           1278 x 1351.7 x 591mm (5520)
                                           1110 x 1210 x 532.5mm (4710)
 General                                   1110 x 1210 x 529.5mm (4720)
           Weight                          77.9Kg(55"), 66.5Kg(47")
           Antenna input                   One 75 ohm external input terminal
                                           for UHF/VHF/Cable
           Screen size                     139cm(55"),119cm(47"), 16:9 Aspect Ratio
           Scanning type                   DTV : 1080I @ 33.75KHz
                                           NTSC/DVD: 480p @ 31.5KHz
                                                      1080I @ 33.75KHz
           CRT size                        7"
           Sound system                    3D Stereophonic sound
           NTSC voice                      Stereo, Sound multiplex
           Voice output                    15W/ch (Main L/R)
           Antenna input                   2EA
           NTSC AV input                   2pairs (S-Video/Video/L/R)
           NTSC AV monitor output          1pair(Video/L/R)
           Component input                 2pair(Y/Pb/Pr)
           NTSC AV input                   1pairs(S-Video/Video/L/R)

1-2. Features of product
   7" Pure Flat Picture Tube
   Digital 3D Comb Filter
   Video Noise Reduction
   1080i(HD), Line doubled to 480p(NTSC)
   Velocity Modulation Scanning
   Dynamic Focus System
   Auto channel Programming
   Black Level Expender

 Explanation for circuit operation

2. Power

2-1. Outline
This power is a power supply of 230W to provide a power for 55"/47"CRT Projection TV.

2-2. Block diagram
The block diagram of this power is as follows.

2-3 Composition of power supply
This power supply is formed in Fly-back type to provide various powers.
The design specification of this power supply is as follows.
1) Input power: 120Vac (+/- 10%), 60Hz
2) Power consumption : 230W
3) The second power supply is shown in table 1-1. (Final power supply)

                                                               Explanation for circuit operation

No. Position Kind Purpose Current Remark
 The second power supply
 No.    Position    Kind    Purpose                             Current          Remark
 1      T802       200V     CRT AMP B+                           80mA
 2      T802       135V     HIGH VOLTAGE B+                      900mA           F/B LINE
 3      T802        12V     GENERAL PURPOSE                      600mA
 4      T802        9V      GENERAL PURPOSE                     1000mA
 5      T802        5V      GENERAL PURPOSE                      400mA
 6      T802        5V      GENERAL PURPOSE                      750mA
 7      T802       6.3V     HEATER B+                            650mA
 8      T803       +25V     SUB-DY AMP B+                        900mA           F/B LINE
 9      T803       -25V     SUB-DY AMP B+                        900mA
10      T803        30V     GENERAL PURPOSE                      100mA
11      T803       +7.5V    GENERAL PURPOSE                      100mA
12      T803       -12V     GENERAL PURPOSE                      300mA
13      T803       +15V     AUDIO AMP B+                        2000mA
14      T803       -15V     AUDIO AMP B+                        2000mA
15      T801        5V      STAND-BY B+                          500mA
                            < TABLE 1-1 > The second power supply
2-4 Explanation for power supply operation
 1) Power supply and STAND-BY power
   The voltage via a bipolarity power code (PC801) goes through a line filter area composed of
   EMI filter (L801, L802, L827), X-capacitor (C801, C802, C803) and Y-capacitor (C804,
   C805), is rectified and smoothed (C-806) in bridge diode (D801 -D804).
   This voltage provides a power for STAND-BY trans (T-801) and TOP232P of STAND-BY
   power IC (I801) and the second TRANS supplies a STAND-BY power for U-COM.
2) Main power start
  When the U-COM supplies a PWR SWITCH ON signal for Q801 base via PA802 connector, a
  positive terminal relay (RLY1) starts and AC power is rectified and smoothed (C809, C816) in
  a bridge diode (D-808) via a Y-capacitor (C-811, C812).
  The voltage before smoothing supplies a starting voltage for No.4 terminal of STR-F6656
  (I802, I803) via (R809+R817) and (R823+R824).
  When STR-F6656 starts, the voltage via a coil bead (L825, L826) goes to coil P of trans and
  then to drain (Pin No.3) of internal power MOSFET of STR-F6655. The voltage flowing in coil
  D supplies a power for terminal No.4 of trans STR-F6656.
  Then, a current flows via R813 and R818 without going through (R809+R817) and
  (R823+R824). That is, (R809+R817) and (R823+R824) supplies a current only at starting.
3) Specification of STR-F6656
  The STR-F6656 is a power MOSFET and control IC built-in Fly-back type of Hybrid IC for
  switching power.
  The feature of this IC is a Quasi-Resonance associated operation IC that the number of parts
  added to external is small, various protection functions (protection from overcurrent,
  overvoltage and overheat) are offered and a power loss decreases by lowering an originating
  frequency at STABD-BY.

  Explanation for circuit operation

The detailed specifications of this IC are as follows.

Terminal No.             Symbol              Name                                   Functions
     1                     O.                Overcurrent/Feedback terminal          Overcurrent detection signal
        2                   S                Source terminal                        MSOFET source
        3                   D                Drain terminal                         MOSFET drain
        4                  Vin               Power terminal                         Control circuit power input
        5                 GND                Ground terminal                        Ground


                        Symbol                    Functions
                        O.V.P                     Overvoltage protection circuit built-in
                        T.S.D                     Overheat protection circuit built-in

                                                                         Specifications                            Condition for
Item                                Terminal       Symbol                                               Unit
                                                                 MAX         TYP           MAX                     measuring
Operation start power voltage 4 - 5                VIN(ON)       14.4         16           17.6         V
Operation stop power voltage 4 - 5                 VIN(OFF)        9          10            11          V
Circuit current at operation 4 - 5                 IIN(ON)         -            -           30          mA
Circuit current at non-operation4 - 5              IIN(OFF)        -            -          100                        -
Maximum OFF time                        -          TOFF(MAX)      45            -           55           SEC

Minimum Quasi-Resonance 1 - 5                      Tth(2)          -            -          1.0           SEC

signal input time
Minimum OFF time                        -          TOFF(MIN)       -           -            1.5          SEC                 SEC

OOP/FB terminal threshold voltage 1 - 5            Vth(1)        0.68        0.73          0.78          V            -
OOP/FB terminal threshold voltage 2 1 - 5          Vth(2)         1.3        1.45           1.6          V
OOP/FB terminal outflow current      1-5           IOCP/FB        1.2        1.35           1.5         mA
OVP operating power voltage 4 - 5                  VIN(OVP)      20.5        22.5          24.5         V             -
Latch circuit sustaining current 4 - 5             IIN (H)         -           -           400
Latch circuit clearing power voltage 4 - 5         VIN(LA.OFF)    6.6          -            8.4          V
Overheat protection temp.             -            Tj(TSD)       140           -              -

                             < Electrical features of control area:(Ta=25 ), Vin=18V >

                                                                         Explanation for circuit operation

ITEM                       Terminal   Symbol                                   Unit
                                                MIN     TYP        MAX
Voltage via drain-source     1-2       VDSS     650        -        -           V
Drain leakage current 1 - 2IDSS          -       -         300
ON resistance               1-2       RDS(ON)    -          -    3.90          OHM
Heat resistance              -          ch-F     -          -    1.63          C/W
Switching time               1-2        Tf       -          -     250           SEC

4) Explanation for operation
   When the VIN terminal (Pin No.4) voltage of STR-F6656, which is charged in C815 and C822
   via starting resistance (R809+R817) and (R823+R824) at the early starting, reaches 10V, a
   control circuit in SRT-F6656 starts.
  Since the circuit current before 6656 operation is limited to 400              (MAX), a high starting
  resistance can be used.
  Because a sustaining current of latch circuit in 6656 is set to 500                 (MAX), this starting
  resistance needs to be set so that 500     or more current flows though AC input power is the
  Because the time until control circuit in 6656 starts is determined after AC input voltage is
  input by (R809+R817), (R823+R824) and C815, C822 product, the power start gets slow if
  C815 and C822 is set too high.

  The voltage via a coil D (d1) of trans (T802. T803) is rectified and smoothed after operation
  of 6656 and a stable voltage is supplied for Vin terminal. For coil D1, approx. 15.5V voltage is
  rectified and smoothed via R813, R818, D810, D813, C815 and C822 and approx. 15V
  voltage is supplied for Vin terminal of 6656.
  Since VIN (OFF) voltage is set to 10V (TYP) in 6656, the terminal voltage supplied for Vin
  terminal should not be less than 10V (15V at present). The voltage of coil d1 should be set
  over operation stop voltage (VIN(OFF)=10V(MAX)) and under OVP operation voltage
  (VOVP=16V(MIN)) at normal operating state.

5) Protection circuit
 5-1) OCP circuit
   This is an overcurrent protection circuit of pulse by pulse type that the peak of MOSFET
   drain current is detected by 1 pulse and the output of oscillator is reversed.
   To detect the MOSFET drain current, R810 and R820 are connected between source
   terminal (Pin No.2) and GND terminal (Pin No.5) of MOSFET and the voltage drop is input to
   OCP/FB terminal. The threshold voltage of OCP/FB is set to approx. 0.78V for GND.

 5-2) Latch circuit
  This circuit stops the operation of power circuit, keeping the oscillator output low when the
  overvoltage protection circuit and overheat protection circuit are operated.
  Because the circuit current gets less than 400uA when Vin terminal voltage is lower than
  operation stop voltage (10V), it begins to increase. Because the circuit current increases
  again when it reaches operation start voltage (16V), it decreases. Therefore, this circuit
  prevents the Vin terminal voltage from rising, making it goes up and down between 10V and

 Explanation for circuit operation

 5-3) Overheat protection circuit
  This circuit operates the latch circuit when the frame temps. of hybrid IC goes over 140

 5-4) Overvoltage protection circuit
  This circuit operates the latch circuit when Vin terminal voltage goes over 22.5V and protects
  the Vin terminal of control circuit from overvoltage. The normal Vin terminal is supplied from
  an auxiliary coil of trans and this voltage is proportioned to the output voltage. Thus, this
  circuit works when the voltage detection circuit is open and the second overvoltage is output.

3. Deflection
  3-1 Outline
   This deflection PCB is composed of deflecting part to deflect 47", 55" CRT Projection TV and
   7" CRT, high voltage generator part, dynamic focus part, ABL part and VM part.

 3-2 Block diagram

                                                                Explanation for circuit operation

3-3 Organization of deflecting part
This smoothing part is designed to deflect a 55" CRT Projection TV and correct a screen. The
design specifications of this deflecting part are as follows.
 1) Working frequency: Horizontal frequency (31.45KHz, 33.75KHz). Vertical frequency
 2) Vertical / Horizontal deflection
     This deflection IC used in this deflecting part is TDA4856, the latest HC Control IC of
     PHILPS. Co. Ltd. The main functions of this IC are shown below.
  a. All functions concerned with vertical and horizontal deflection can be adjusted by HC
      control of U-COM.
  b. The geometrical correcting part such as V-S linearity, VC linearity, trapezoid, Side-pin W-
      S, parallelogram and Side-pin balance are includes in the IC.
  c. Twenty built-in D/A converter channels are adjustable respectively.
  d. A vertical S-C correcting circuit is built in.
  e. The amplitude and phase of a horizontal dynamic focus linked with horizontal size can be
  f. A vertical dynamic focus circuit linked with vertical size is included.
  g. A horizontal moire canceller circuit is built in.
  h. A Sync On Green circuit is built in.
  i. Vertical / Horizontal size can be controlled.
  j. Vertical /Horizontal position can be controlled.
  k. Vertical /Horizontal Sync of bipolarity can be input.
  l. A vertical blanking generating and video clamp generating circuit are included. (Sand
     castle output)
  m. A vertical waveform of bipolarity is output.
  n. A horizontal lock detecting circuit is included.
  o. Low jitter

3-4 Explanation for operation

1) Vertical / Horizontal deflection IC circuit part
  HD and VD signal supplied via connector PA402 in A/V board is input to H-in (Pin No.15)
  and V-in (Pin No.14) of deflection IC as Sync. The input Sync goes through an internal Sync
  processor and is output as H Drive to H-out (Pin No.8).
 At this time, the internally processed Sync isn't affected by polarity and for H Sync, a
 composite signal can be input. For H-OUT, the duty can be selected and controlled to 40,
 50, 60% (+/- 3%) by I2C control. Free Run frequency at No Sync can be adjusted by I2C
 control. Dividing a collector pulse from horizontal deflection, an internal PLL is taken after
 FBP (Pin No.1) input and the phase is adjusted to horizontal Sync.
 In this IC, all geometrical compensating waveforms related to horizontal are output from E/W
 (Pin No.11), supplied for a horizontal B+ generator in a horizontal drive part, added to a
 horizontal B+ waveform in the form of parabola and provided for D1 of horizontal output TR
 (Q402). The horizontal dynamic focus signal from this IC is first amplified via an amplification
 part (IF 11).
 2) Horizontal drive part
    This horizontal drive part consists of horizontal B+ supply part and horizontal output part.

Explanation for circuit operation

2-1) Horizontal B+ supply part
 This horizontal B+ supply part cuts off horizontal B+ power by two TRs, using a Darlington
 circuit. DC voltage supplied for E/W terminal (Pin No. 11) in deflection IC(I403) is input to EW
 1st inversion circuit IF11 PIN2 by using EW waveform and then output to PIN1. The amplified
 EW waveform is output to PIN7 and connected with B+ drive circuit, which is supplied for the
 Darlington circuit composed of Q403 and Q404 through Q311 connector and C417, R429
 horizontal. 135V via D415 and R433 is supplied for Q403, Q404 connector. When 100V is
 supplied for Q403 base, DC voltage (100V-110V) amplified in Q404 and E/V compensating
 waveform supply B+ for horizontal output Tr (Q402) by R409 and D405 via pin drive trans
 T402 and dummy trans T403.
2-2) Horizontal output part
 The horizontal output part makes a voltage and current enough for horizontal deflection
 using a power supplied from horizontal B+ generator and drives H drive trans (T401) after
 application to Q401. The drive pulse via H drive trans is supplied for the base of horizontal
 output Tr (Q402) base and operates the horizontal output Tr. When it works. a horizontal
 output voltage is made by using a horizontal deflection coil and retrace condenser (C407,
 C408). At this time, the horizontal output voltage is approx. 1000V to 1200V and the retrace
 time is approx. 4.0 sec. The horizontal output current via the deflection coil is supplied for CS
 condenser (C409, C410).
3) Vertical drive part
 The vertical drive part consists of +12V, -12V positive power, using TDA8172, vertical output
 IC of SGS-THOMSON Co. Ltd. and performs vertical deflection and vertical-related
 geometrical correction. The main operations of this vertical drive part are as follows. The
 vertical waveform and vertical correction signal outputted to the vertical output terminal
 (PIN12, PIN13) of vertical/horizontal deflection IC (I403) are input to inverted input terminal
 (I412) of vertical output IC (I412), amplified in the vertical output I, outputted to the output
 terminal (PIN6) and applied to vertical deflection coil. For the current via the deflection coil,
 DC-feedback via R311 and AC feedback via C318 are executed.
4) High voltage generating part
 The high voltage generating circuit uses a high voltage generator for projection, differently
 from the conventional FBT method. This HVG has been developed by PHILIPS CO., LTD.
 and performs the following operations. The HVG module is composed of 10 pins, 3 EHT
 output holes and 1 focus output hole. Each terminal is displayed below.
  PIN 1 : NC
  PIN 5 : NC
  PIN 6 : NC
  PIN 8 : ON/OFF (ON/OFF 5V)

                                                               Explanation for circuit operation

 When B+ 135V is supplied and +5V is applied, approx. 31KV high voltage and 11.6KV focus
 voltage are generated automatically. If EHT of HVG is outputted more than 35KV, HVG
 module starts over voltage protection to stop the high voltage.

5) Spot killer components
 Approx. -220V voltage made by using HVG high voltage output voltage is supplied from HVG
 PIN4, rectified and smoothed to D819 and C425 and used as spot killer power. After this
 power is divided into R448 and R449 normally, a voltage near to -20V via R465 is supplied
 for CRT board GRID 1 via connector PA13 G1. But, at first AC power ON, the spot killer
 signal supplied via a connector PA15M in main board is provided for the base of Q412. At
 AC power OFF, a voltage near to -220V via Q414 is provided for GRID 1 of CRT board via
 G1 of connector PA16M. As a result, the screen gets dark to prohibit the generation of a

6) Dynamic focus voltage generator
 The dynamic focus voltage provides a parabola waveform conforming to CRT spec.
 (horizontal:1000V, vertical:200V) for CRT to make the focus of 7" CRT optimum. A D/F
 waveform from 1403 pin32 is amplified approx. 100 times in an amplifying circuit composed
 of OP AMP and a parabola waveform is amplified approx. 1000Vp-p in an amplifying circuit
 composed of QF11, 12, 13. Then, they are input to QF14 base. The horizontal waveform of
 1300Vp-p left in T402 terminal No.16 is rectified and smoothed to DF13, 12, RF17, CF11, 12
 and supplied for QF14 collector as B+ for dynamic focus.

7) ABL input part
 The ABL current supplied from main board via the ABCL terminal of a connector PA401
 flows in via FBT PIN2. Then, the current amount is detected, the BCL circuit is operated in
 the main board and the maximum current amount is controlled. If a beam current begins to
 flow about 1.5mA, the ABL circuit will work and if about 1.8mA, the ABL feedback circuit will
 work. Therefore, be careful not to be more than 1.8mA.

8) VM (Velocity Modulation) outline correction part
 The outline correction circuit is operated in exclusive correction IC, IV11 (STK396-130). The
 VM waveform made in the main PCB is input to the deflection PCB PA401 PIN1. The input
 1Vp-p signal is input to IV11 PIN1. The input signal is amplified about 100 to 120Vp and
 output to IV11 PIN9. Then, it is input to IV11 PIN10 via the circuit composed of VM coil PV11,
 12, 13. The power of +12V and +135V GND are used.

 Explanation for circuit operation

Explanation for circuit operation

     Explanation for circuit operation

Explanation for circuit operation

     Explanation for circuit operation

Explanation for circuit operation

     Explanation for circuit operation

 Explanation for circuit operation

4. Video signal process
  4-1. Block Diagram

 4-2. Video processor
    This part switches and processes DTV input, DVD input, external video signal and TV

  1) Signal input/output
     The signal input is composed of 2 pairs of NTSC TV signals (2 tuners), 3 pairs of NTSC
     external inputs (Video, S-VHS 3 pairs respectively), 2 pairs of component inputs and 1 pair
     of monitor outputs.

  2) Video input switching

     2 pairs of NTSC TV signals and 3 pairs of NTSC external input from the main tuner
     (TU701) and sub tuner (TU702) is switching in a IA01 AV switch and 2 pairs of component
     input is switching in a IA05 video selector.
     CXA1855Q outputs 4 pairs as switching IC with 5 pairs input and CXA2151Q outputs a
     YCbCr signal by 4 pairs input. The output signal is amplified 6dB.
     CVBS (Main) and Y, C signal from QXA1855Q are input to 3D Comb-filter (ICB1), 4801
     format between CVBS (Sub) and IA05 output is input to ICD1 and 480P and 10801 signal
     of IA05 are input to IC201.
     ICB1 performs Y, C division and YCNR (YC Noise Reduction) function, equipped with
     internal AD converter and 4M bit frame delay memory as a three-dimensional Y, C divided
     Y/C signal from ICB1, caption data decoded in caption IC (IC206) and 4801 signal of IA05
     are input to the main video processor IC, VSP9407B (ICD1).

                                                                Explanation for circuit operation

   When PIP function is executed in `different application mode' signal processing VSP9407B,
   the video signal corresponding to a sub screen (Sub CVBS from TU702) is input.
   VSP9407B performs a scan rate conversion of main video signal and sub video signal from
   480I to 480P, overlaps the main video and sub video to convert to PIP screen and outputs
   them to IC201 (CXA2101Q) in YcbCr-H-V format. And, a multi component processor,
   IC210 performs a final switching for YcbCr-H-V signal of VSP9407B and YUV (480P,
   10801) signal from IA05.

  3) Video signal processing
    CXA2101 IC can switch OSD by 4 pairs of YUV input and RGB OSD input and react two
    kinds of color difference signals of NTSC (YUV) and HD (YpbPr) by YUV to RCB matrix
    switch function. It can also control ABL/ACL gain and start level by contrast, brightness,
    sharpness, color, tint (Hue) control function and ABL/ACL input terminal. And, it performs
    black/white gradation correction and has a voltage input terminal for DC play ratio control.
    CXA2101 performs LTI (Luminance Signal Edge Enhancement Setting) and CTI (Color
    Difference Signal Edge Enhancement Setting), and generates a signal for VM.
    CXA2101 (IC201) performs a final signal processing after switching YCbCr (480P) signal
    from VSP9407B and YUV (480P, 1080I) from CXA2151 and outputs the RGB signal
    controlled by user control to CRT drive part after mixing it with OSD signal.

5. Sound

 5-1 Switching part

   For NTSC TV input, SIF signal from main tuner is input to IC602 (MSP3421) PIN67, and 3
   pairs of external inputs, audio signals are switched in IA01, output to #32 (R), #33(L) and
   input to IC601 #47 (Main L), #48 (Main R).
   For audio signals of component 1,2 (DTV, DVD compatible) input, component 1 is input to
   #50 (L), #51 (R) and component 2 is input to #53(L), #54(R).

 Explanation for circuit operation

 5-2. Sound Processing

    As shown above, the MSP4321 outputs the main L/R to PIN27, 28 after switching NTSC
    S/F external input L/R and component 1,2 (DTV, DVD compatible) L/R signals. The main
    functions of the MSP3421 are volume control, equalizing and balancing. The SIF signal
    that is input to #67 goes through AGC, A/D, demodulation and demphosis block. The audio
    signal detected by FM is demodulated and output.
    For sound output, the main L/R that is output from IC601 PIN27, 28 is input to 1601
    (FDA7265) AMP PIN7, 11 and the sound is amplified from FDA7265 and connected with
    L/R speaker.

6. Convergence part

 6-1. Outline
  This convergence supplies a constant waveform for R, G, B SUB-DY to evenly show R, G, B
  screen of 55" CRT Projection TV.

                                                                Explanation for circuit operation

 6-2. Block Diagram

 6-3. Composition
  1) CM0021AF
     As a digital convergence IC, this inputs HBLK and VBLK, adjusts a register in IC, makes
     and supplies a digital convergence waveform of RH, GH, BH, RV, GV and BV. It also has
     Save U-Com function and controls EEPROM (I503: 24WC32) which stores the
     convergence control data by the order of Master U-Com.

The main features of this IC are as follows.
 1-1) Feature
        Multiscan : NTSC/PAL/HDTV, Progressive/Interlace
        6ch/16bits Digital Outputs for Convergence Correction
        2ch Analog Outputs for Dynamic Focus
        Test Pattern Generator for Convergence
        2-Port IIC Interface for EEPROM and U-COM

 1-2) Data Capacity
        504 words : Fine Adjustment
        33 words : Coarse Adjustment
        9 words : Dynamic Focus
        582 Words in Total

 Explanation for circuit operation

2) CD0031AM
This converts the digital convergence waveform to analog waveform as a 6-channel, 16 bit D/A
converter IC for digital convergence.

The features of this IC are as follows.
   High Sampling Rate Operation : 1MHz
   Differential Non-Linearity Error : +/- 1 LSB
 => Operate on 1H to Over 3H Application
   Center Voltage Output
 => Same Electrical Characteristics of Center Voltage Output and RH, GH, BH, RV, GV, BV's
     Zero Cord Outputs
   Mute Function

 3) Others
  3-1) KF353
   This is used as a level shift and low pass filter (1506-1511) of RH, GH, BH, RV, GV and BV.
  3-2) STK392-020 (1940, 1905)
   This uses a 3 channel AMP to apply RH, GH, BH, RV, GV and BV via level shift and low
   pass filter (1506-1511)to a Sub-DY coil.

                                                                 Explanation for circuit operation


The video signal that is first amplified in PGB processor is input to video AMP in approx. 3.5Vp-
p level. TDA111Q used as a video AMP is a 13Mhz band AMP which outputs a video near to
Vdd according to gain control voltage when Vdd is 200V. The following figure shows the internal
block diagram of TDA6111Q.

                                  Block diagram of TDA6111Q

There are two cathode outputs and a independent feedback output. Low input (Vdd) is 12V and
high input (Vddh) is 200V. A peaking circuit is designed in Amp IC input and output part for high
band compensation. The entire output gain is about 34db.


                                    When the screen
                                    doesn't turn up
                                    AV/RF Signal
                        YES                                  NO                             Check
                                    Is there OSD                                            the tuner
                                    on the screen?                      OSD                 (TU701 & TU702

 No screen mode               1             No screen mode          1           Check LA1 TV video signal
 1. TV external input                       1. TV (RF signal)                   Main tuner (TV701 CVBS #41)
 2. Component input                         2. AV input                         Sub tuner (TV702 CVBS #27)


 Check LA5 input/output
 Input                                         Check LA1 video signal
 - COMP1:Y-#43, Cb/Pb-#42, Cr/Pr-#41           Video1:#43-CVBS, #45-Y, #47-C
 - COMP2:Y-#3, Cb/Pb-#2, Cr/Pr-#1              Video2:#1-CVBS, #3-Y, #5-C
 Output                                        Video3:#7-CVBS, #9-Y, #11-C
 - Y-#27, Cb/Pb-#26, Cr/Pr-#25

                                                                              Check LA1 output signal
 Check input signal                                                           1. CVBS_Main:#34, Y:#37, C:#39
                          1                                                   2. CVBS_Sub:#17
 1. 480i                                        Check external
 2. 480p/1080I                                  input signal
                                                                                 2                1

                                                                                      Check ICB1 input/output
                                                                                      Y/CVBS_Main Input:#88
     OSD                                                                              C Input:#96
                                                                                      Y/CVBS_Main Output:#84
                                  Check IC201 input/output                            C Output:#83
                                  -ICD1 Output
 Check I701 OSD signal            Y:#69, Cb:#68, Cr:#67, H:#66, B:#65
 R, G, B:#64, #63, #62            -IA5 Output
 BL:#61                           Y:#5, Cb:#4, Cr:#3
                                                                              Check ICD1 input/output
                                  R, G, B:#50, #51, #52
                                                                              1. Y/CVBS_Main:#55, C_Main:#54
                                                                              2. CVBS_Sub:#52
                                                                              3. 480i:#46(Cr), #47(Y), #48(Cb)
                                  R, G, B:#35, #37, #39
                                  HS:#29, VS:#28
                                                                              Y:#2, Cb:#79, Cr:#76, H:#17, V:#23


                                                                                     TROUBLE SHOOTING

                                       When no sound
                                       is heard

                                   Check IC601 sound signals.
                                   #27, #28                                    YES


                              Check IC601 input sound signals.
                              SIF:#67 A/V:#47, #48
                              Component1:#50, #51
                              Componen2:#53, #54


IC601              NO                                   Chack                        YES
#38, #39, #40           C604, RC605
                        C605, RC615                     IC601#47, #48
Check B+                DC603, C606                     IA01#32, #33
                        Check C612
  YES                                                             NO               NO             YES

  IC606            NO
                        LC601, C601, CC601                                                      Check
  #11, #12, #13         RC601, L601, C618           Check         Check            Check
                                                    IA01                                        RC606
  #65, #66, #80         CC615, LC602, C602                        IA01             IA01
                        Check CC607                 #44,#46                                     RC607
  Check B+                                                        #2,#4            #8,#10
                                                    sound.                                      C608
                                                                  sound.           sound.


                                                            NO                NO
  Check                 Check
  IC601 #2, #3          DC601, DC602                                                        Check
  I2C                   RC602, RC603                Check               Check
                                                    CC120,CC122         CC102CCI04C
                                                                                            RCT13, RCT14
  YES                                               CCK2,CCK3           CK5CCK6
                                                    RCK4, RCK5          RCK9, RCK10
                  NO                                                                        DCT12, DCT14
 Check                                              DCK5, DCK6          DCK13, DCK14
 IC601 #21              Check                                                               DCT15, DCT16
                                                    DCK7, DCK8          DCK15, DCK16
 Reset                  C603, RC604                                                         DCT17

  YES                                                                                                      #3



           YES                                         NO                    NO                NO

 Check                 Check                                                                   When component
                       X601,CC605        When IC601            When component
 IC601#71, #72                                                                                 IC601#53 #54
 X-TAL                 CC606             #67 SIF doesn't       IC601#50 #51
                                         work, check           sounds aren't                   sounds aren't
                                         TU701 tuner.          heard,                          heard,


Check OC614, C617,
C607, OC613 and
replace IC601.
                                                RC608, RC609, C610                         Check
                                                C611, CCK10, CCK11                         RC610, RC611, C612
                                                RCK17, RCK18                               C613, CCK12, CCK13
            END                                 DCK22, DCK23                               RCK22, RCK23
                                                DCK24, DCK25                               DCK26, DCK27
                                                                                           DCK28, DCK29


                                           Check I650                                               YES
                                           L/R Input:#7, #11, L/R Output:#2, #4, #8, #10
                                           A MUTE:#5


                                                                                            TROUBLE SHOOTING

                                                  No raster.

                                 Check IIC bus communication between main assy
                                 and I403

   Vertical deflection                                                                NO       Check main
                                                                                               assy, 1403

                                       Check I403 #8 (H-drive output)




Check D drive signal in Q401 collector            Check H drive signal input in Q402 base

                                                                                   6Vp-p       NO

                                                                                                Check Q416

                                                      Check H driver B+ voltage in T402 #7
 Check Q404 collector 135V

                                                                                   2Vp-p            Check
               Check R443


                Check R443

                            Check PB801 135V                           When power isn't supplied

 Output E/W signal in I401 #7                        Horizontal drive B+ is input to Q403 base


                                                         Voltage waveform of Q402 collector is
                                                         shown below.
 If resistance between Q425 collector and GND
 is near 0

◦ Jabse Service Manual Search 2024 ◦ Jabse ◦ Other service manual resources online : FixyaeServiceinfo