DAEWOO DSJ-4710CRA, DSJ-5510CRA, DSJ-4720CRA, DSJ-5520CRA Service Manual

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DAEWOO ELECTRONICS Corp.

Service Manual

Feb. 2004

S/M No. :DSJ112FEFO

REAR PROJECTION TV CHASSIS : SJ-112

MODEL : DSJ-4710CRA/5510CRA

DSJ-4720CRA/5520CRA

Contents

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

9. PRINTED CIRCUIT BOARD

1) Main PCB 85

2) Power PCB

3) AMP PCB

4) CRT PCB 88

5) DEF PCB

6) UNION-1 PCB(CONTROL, SIDE)

7) UNION-2 PCB(CONV MODULE, REAR IO 91

10. EXPLODED VIEW

1) DSJ-4710 92

2) DSJ-4720

3) DSJ-5510 94

4) DSJ-5520

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 state.

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 used.

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) 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

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) Rear 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) Right NTSC AV input 1pairs(S-Video/Video/L/R)

General

Image

Voice

External Input/ Output

3. Specifications of remote control

Power

TV/VCR/CATV

Channel number (0-9)

Use to select channel directly 0~9

It returns to previous channel.

TV/Component

TV ->

Component 1

Component 2

-> TV

Mute

Sound Mode

This feature allows you to choose the mode , Each time the button is pressed, it rotates from Normal

Music

Movie

News

User.

Bilingual Broadcasting

This feature allows you to select the language while broadcasting.

100

Use it when selecting a channel

number of over 100

Use it to make picture adjustment,

screen format, sound adjustment,

input selection, and utilities.

TV/VIDEO

Use this function to make

video input selection.

It changes in the following sequence

VIDEO1

-> 2-> 3->

VOLUME

Dolby Virtual

CHANNEL ADD/ERASE

This feature either memorizes the

current channel or erases a channel

that has previously memorized.

Sleep Timer

This feature is used to set up the time

of automatic turn off.

VCR Function

REW, PLAY, FF, STOP, REC, PAUSE

Caption

This feature allows you to choose the caption. Each time the button is pressed it rotates from CC1

CC2

CC3

CC4

Off

ANT PIP

STILL SWAP

Screen Size

This feature converts the screen size by changing its aspect ratio. Each time you press the button, it will be changed from

16:9

4:3

Panorama

ZOOM1

ZOOM2

Auto Picture

Standard -> Cinema -> Dynamic -> User

PIP

TV/Video

Position

DISPLAY

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.

(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)

DY rectangle projection

GENTERING MAGNET

VM COIL

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.

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)

SCREEN(R/G/B)

FOCUS(R/G/B)

[Figure 2. Exterior view of focus-pack]

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 order.

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 order.

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 center.

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).

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)

Figure 4. Control of R, G, B raster

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

32CH)

Coordinates setup:x=0.275 0.005 / y=0.275 0.005 Initial data (S8)

R DRV : 31 (RED DRIVE) G DRV : 40 (GREEN DRIVE) B DRV : 31 (BLUE DRIVE) R CUT : 61 (RED BIAS) G CUT : 64 (GREEN BIAS) B CUT : 61 (BLUE 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

7. CRT AMP

Explanation for circuit operation

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

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)

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

General

Image

Voice

External Input/ Output

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 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

No. Position Kind Purpose Current Remark <Table 1-1> The second power supply

< 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

1O.

Overcurrent/Feedback terminal Overcurrent detection signal

P./

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

Item Terminal Symbol

MAX TYP MAX

Unit

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-operation

4 - 5 IIN(OFF) - - 100 Maximum OFF time - TOFF(MAX) 45 - 55 Minimum Quasi-Resonance 1 - 5 Tth(2) - - 1.0 signal input time Minimum OFF time - TOFF(MIN) - - 1.5 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 >

SEC

Condition for measuring

SEC

Explanation for circuit operation

Specifications

ITEM Terminal Symbol

MIN TYP MAX

Unit 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

lowest. 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

16V.

5-3) Overheat protection circuit

This circuit operates the latch circuit when the frame temps. of hybrid IC goes over 140 (MIN).

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 (60Hz)

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

adjusted. 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 I

C 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 2 : ABL ( BEAM CURRENT INFORMATION ) PIN 3 : GROUND (AUXILIARY VOLTAGE ) PIN 4 : AUXILIARY VOLTAGE ( -220V ) PIN 5 : NC PIN 6 : NC PIN 7 : OVP ( TEST POINT FOR OVER VOLTAGE PROTECTION ) PIN 8 : ON/OFF (ON/OFF 5V) PIN 9 : GROUND PIN10 : VB+ ( POWER SUPPLY VOLTAGE )

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 spot.

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

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 signal.

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 IC. 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).

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