SANYO CE28DF1-C Service Manual

Colour Television Service Manual

Model CE28DF1-C

(W.EUROPE)

Service Ref. No. CE28DF1-C-00

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

Note This TV receiver will not work properly in foreign countries where the television transmission system and power source differ from the design specifications. Refer to the specifications for the design specifications

PRODUCT CODE 111327213 ORIGINAL VERSION Chassis No. EB3-A

Specifications

Power source AC 220~240V 50Hz Television system System B/G, I,L/L’ Colour system PAL/SECAM Receiving channel VHF: E2~E12

CATV: X,Y,Z, S1~S41

UHF: #21~#69 Aerial input impedance 75ohm AV terminal

AV1 : 21-Pin SCART Terminal AV2 : 21-Pin SCART Terminal

AV3 : Cinch Terminal Sound output (CONT) 10 watts X2 Picture tube 70cm diagonal, 110 degree (Visible picture diagonal) 66cm Dimensions 740(W) X 595(H) X 494(D)mm Weight 31.6 Kg

Part No. SKSM0273 SEPT 1998 issue 1

-2-

SAFETY PRECAUTION

An isolation transformer should be connected in the

power line between the receiver and the AC line when

a service is performed on the primary of the converter

transformer of the set.

Comply with all caution and safety-related notes

provided on the cabinet back, inside the cabinet, on

the chassis or the picture tube.

When replacing a chassis in the cabinet, always be certain that all the protective devices are installed properly, such as, control knobs, adjustment covers or shields, barriers, isolation resistor-capacitor networks etc.

Before returning any television to the customer, the service technician must be sure that it is completely safe to operate without danger of electrical shock.

The primary source of X-RADIATION in the television receiver is the picture tube. The picture tube is specially constructed to limit X-RADIATION emissions. For continued X-RADIATION protection, the replacement tube must be the same type as the original including suffix letter. Excessive high voltage may produce potentially hazardous X-RADIATION. To avoid such hazards, the high voltage must be maintained within specified limit. Refer to this service manual, high voltage adjustment for specific high voltage limit. If high voltage exceeds specified limits, take necessary corrective action. Carefully follow the instructions for +B1 volt power supply adjustment, and high voltage 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 which safety can be of special significance. It is particularly recommended that only parts designated on the parts list in this manual be used for component replacement designated by mark ! . No deviations from resistance wattage or voltage ratings may be made for replacement items designated by mark ! .

-3-

BLOCK DIAGRAM

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

SP X2

Deflection

CRT

T471 FBT

Q432

H-OUT

Yoke

Speakers

L,R

Key switches

CPU

IC701

IC731

MEMORY

B-Y in

IC270

1H DELAY

(TDA4661)

141612

313028

B-Y out

R-Y in

R-Y out

B-Y out

B-Y in

R-Y out

R-Y in

R,G,B

B7:8V

1819203743

B out

G out

Q431

R out

B4:24V

H-Drive

V out

H out

IC101

(TDA8361)

Digital Control

3: Colour, 4: Bright,

5: Contrast, 6: Sharpness

34,35

SCL

SDA

21. 22

SCL

SDA

51 52

G out R out

Teletext

Decoder

IF in

IF/COLOUR/

DEFLECTION

242322

46 45

SAW

X101

R,G,B

B in

G in

R in

C in

TV/AV

V in

(EXT)

V in

TV out

TV Out

Sound

Trap

TV/AV

SIF in

IC451

(LA7833)

B7:8V

Audio L,R

Audio Unit

Vert. AMP.

B8:5V (Main Low3)

B7:8V (Main Low2)

IC352

REG.

B1: 150V(Main High)

IC353

B2: 25V(Audio)

B3: 15V(Main Low1)

B4: 24V(Vert.)

B5: 8V(Main Low2)

REG.

IC351

REG.

SDA SCL

B6:12V (Main Low1)

ANT

B9:5V

(Band/Tuning data)

SDA

SCL

SIF

Unit

A101

TUNER

A InA in (L/R)

A out (L/R)

V in

V out

T311

CONVERTER

TRANS.

IC851

Video Switch

B9:5V

A in (L/R)

IC861

AV2

Audio Switch

A in (L/R)

AV3

V in

Power Circuit

V in

A out (L/R)

Monitor

out

AV1

-4-

1.POWER SUPPLY

The power supply circuit of the EB3-A chassis is composed of a rectifier smoothing circuit, an oscillation circuit, a control circuit and an output rectifier circuit. The AC input voltage is full-wave rectified by the rectifier smoothing circuit, and an unstable DC voltage is generated at both terminals of the smoothing capacitor C307. This voltage is input to the oscillation circuit. The oscillation circuit is provided with a blocking oscillator circuit that switches the switching FET Q301 ON and OFF, and an oscillation frequency and a duty square wave pulse are generated in the input windings according to operation of the control circuit. A squarewave pulse whose size is dependent on the turn ratio of the input and output windings is obtained in the output winding. This is rectified in the output rectifier circuit, and the desired DC voltage is obtained.

2.IF & DEFLECTION (TDA8362)

The IF output signal from the tuner passes through the SAW filter, and it is input to pin45 and pin46 of IC101. The signal input to the IC passes through the IF amplifier, video detection and video amplifier circuits and is output from pin7 as a composite video signal. And after this signal is converted to impedance at Q122, supplies to the video and chroma amplifier stages. The sync.-separation circuit separates the video signals applied to pin13(internal video signal) or pin15(external video signal) to vertical- and horizontal-sync. signals respectively. The horizontal oscillator requires no external components and is fully integrated. The oscillator is always running when the start-pin36 is supplied with 8V. Horizontal drive signal is output from pin37. VR401 is for adjustment of the horizontal centring. The separated vertical-sync. signal from sync. separation circuit passes through the vertical-separation circuit, and applied to trigger divider circuit. The horizontal oscillation pulse and input vertical sync. pulse are monitored by the trigger divider circuit, and switching 50Hz and 60Hz system, the vertical amplitude automatically adjusted for 50Hz and 60Hz. The output signal from the trigger divider is triggered vertical oscillation circuit consisting of C401, R402 and pin42, and vertical drive pulse is output from pin43. VR451 is for changing the amount of AC feedback applied to pin41 and for adjustment of the vertical amplitude.

3.VIDEO CHROMA & R.G.B. (TDA8362)

The composite video signal output from the pin7 of IC101 passes through Q122/Q124, and it is supplied to pin13. The external video signal output from SCART is supplied to pin15. The video signal input to pin13 or pin15 is separated to luminance (Y) signal and chroma signal in IC101. These pins are used in common with H/V-sync. separation input. The peaking of Y signal is adjusted by DC voltage of pin14. (“SHARPNESS”

control) The chroma signal is divided into R-Y and B-Y chroma signals, demodulated in IC101, and output from pin30 (R-Y) and pin31 (B-Y). These chroma signals pass through the 1H delay line circuit (IC270), and they are input to pin29 (R-Y) and pin28 (B-Y). These R-Y/B-Y signals pass through RGB matrix circuit and RGB selector circuit of IC101. The internal RGB signals are generated in RGB matrix circuit and the RGB selector, consisting linear amplifiers, clamps and selects either the internal RGB signals or the external RGB signals input from pin22(R), pin23(G), pin24(B). Selection is controlled by the voltage at the RGB switch control (pin21) and mixed RGB modes are possible since RGB switching is fast. The RGB switch also functions as a fast blanking pin by blanking the RGB output stages; here internal and external RGB signals are overruled. The colour gain is controlled by DC voltage of pin26. (“COLOUR” control) The contrast control voltage present at pin25, and the brightness control voltage present at pin17 controls DC level of RGB signals. The RGB signals are finally buffered before being available at the RGB output pins [pin20 (R), pin19 (G), pin18 (R)].

4.AUDIO OUTPUT(TDA7263M)

The audio signals output from the audio unit are input to pin1(L) and 5(R) of IC581 and passes through the preamplifier circuit and drive circuit, after which it is input to the audio amplifier. The audio amplifier is an SEPP (single-ended, push-pull) OTL type and output to pin8(R) and 10(L) to directly drive the speakers.

5.VERTICAL OUTPUT (LA7833)

An IC (LA7833) is used for the vertical output circuit in this chassis. The vertical drive pulse from pin43 of IC101 is input to pin4 of IC451. This pulse drives IC451, and vertical scanning is performed. In the first half of scanning a deflecting current is output from pin2 and passes through the following path: Vcc(B4) ➞ D451 ➞ pin3 ➞ pin2 ➞ DY ➞ C461 ➞

VR451/R459. An electric charge is then stored in C461. In the last half of scanning the current path is C461 ➞

DY ➞ pin2 ➞ pin1 ➞ VR451/R459 ➞ C461. In this way, an amplifying sawtooth waveform current flows directly to

DY to perform electron beam defection. Next, in the first half of the banking period the vertical drive pulse suddenly becomes OFF, and in order to reduce the current flowing to DY, the current path becomes as follows by the inductance of DY: DY ➞ pin2 ➞ pin1 ➞ VR451/R459 ➞ C461 ➞ DY. Also,

when the charge of DY has dissipated, the current path becomes Vcc24V ➞ pin6 ➞ pin7 ➞ C452 ➞ pin3 ➞

pin2➞ DY ➞ C461 ➞ VR451/R459, and when the prescribed current value is reached, the vertical drive

pulse becomes ON. This completes one cycle.

CIRCUIT DESCRIPTION

-5-

6.HORIZONTAL OUTPUT

A horizontal oscillation signal is output from pin37 of IC101 and switches the drive transistor Q431. This switching signal is current amplified by the drive transformer T431 and drives the output transistor Q432. When Q432 becomes ON, an amplifying current flows directly to DY through C441/442 ➞ DY ➞ Q432 ➞ GND,

and defection is performed in the last half of the scanning period. Next, when Q432 becomes OFF, the charge that had been stored in DY up to that point releases a resonance current to the resonant capacitors C420 and C423 and charges them.The current stored in C420 and C423 is then flowed back to DY, and an opposite charge is then stored in DY. This opposite charge then switches the dumper diode in Q432 ON, the resonance state is completed, and an amplifying current is then flowed again directly to DY through the dumper diode. By this means, deflection in the first half of the scanning period is performed, and when Q432 becomes ON at the end of the first half of the scanning period, deflection during the last half is begun, thus completing one cycle.

7. CPU

Pin description

Pin1: H-sync. input (Horizontal pulse for OSD) Pin2: V-sync. input (Vertical pulse for OSD) Pin3: Colour control output Pin4: Brightness control output Pin5: Contrast control output Pin6: Sharpness control output Pin7: Tint (GND) Pin8: TV/AV output (L:AV mode) Pin9: AV mode selection output-A Pin10: AV mode selection output-B Pin11: Natioal select option Pin12: I

C bus SCL (Serial clock for memory)

Pin13: I2C bus SDA (Serial date for memory) Pin14: Not used (+5V through pull up resistor 22K) Pin15: Ident signal input (L:No signal) Pin16: R/C signal input Pin17: AV1 Scart control signal input (VTR play:L) Pin18: AV2 Scart control signal input (VTR play:L) Pin19: Ignor output Pin20: 50/60Hz output Pin21/22: GND Pin23: Supply Ground Pin24: Oscillator input for CPU Pin25: Oscillator output for CPU Pin26: Supply Ground Pin27: Power supply(+5V) Pin28: Oscillator output for OSD Pin29: Oscillator input for OSD Pin30: Reset input Pin31: Protect signal input (L:Power circuit defects) Pin32: Not used(GND) Pin33: AFT signal input

Pin34: TEXT/16:9 SELECT OPTION Pin35: Key scan 1 Pin36: P-ON(TEXT) Pin37: S-VHS output Pin38: GND Pin39: BG/I Select output Pin40: L/L’ Select output Pin41: NEG/POS Select output Pin42: Not used (GND) Pin43: 16:9/4:3 switch output Pin44: Not used (GND) Pin45: Not used (GND) Pin46: Not used (GND) Pin47: Mute output in no picture(FTZ mute) Pin48: Power ON/OFF output (H:ON) Pin49: Blanking output for OSD Pin50: Not used (Open) Pin51: Green output for OSD Pin52: Red output for OSD

B1 POWER SUPPLY ADJ. TU-AGC ADJ.AFT ADJ.

GREY SCALE ADJ.

FOCUS ADJ.

MAIN BOARD

HIGH VOLTAGE & H-WIDTH ADJ.

V-CENTRE ADJ. H-CENTRE ADJ.V-SIZE ADJ.

-6-

SER VICE CONTROL ADJUSTMENT

CRT BOARD

SECAM

DECODER

VC141

SW301

Main switch

F301 Fuse

VR462 H-WIDTH

Q461

Q462

R232

FOCUS

Q432 H-Output

SW701 SW702 SW703 SW704 SW701A SW705

IC301 POWER

T311 Converter transformer

VR451 V-SIZE

Q431

K802 SCART T erminal-2

T471 Flyback Transformer

SCREEN

KDY

Q313 Power

IC351

Q434

T381

D332

D331

Q701

IC352

IC451 V-Output

Q381

Q771

Q353

VR351 +B ADJ.

Q702

SW451

Q820

Q781

TP-B

Q203

V-CENTRE

IC701

Q784

CPU

Q783

SW220

-> SERVICE

Q202

TP-E

IC270

Q205

1H Delay

Q852

K801

SCART T erminal-1

21P-SCART TERMINAL

Q731

IC790

MEMORY

Q127

Q124

IC101

IF/CHROMA/VIDEO/DEF.

IC280

Q862 Q861

Q800

Q854

Q122

VR401 H-CENTRE

Q853

Q856

IC801

Q855

Q401

TV/AV SW.

Q857

Q761

T121

Q101

Q851

K803

Q741Q128

Q762

TP-D

AUDIO UNIT

VR120 AGC

IC353

TP-A

IC851

K171

A101 TUNER

VR612

R-DRIVE

VR602

B-DRIVE

VR601

B-BIAS

Q651

VR621

G-BIAS

Q601 Q611 Q621Q640

VR611

R-BIAS

EB3-A

-7-

B1 POWER SUPPLY ADJUSTMENT

1. Set VR351 to be mechanical centre before pressing the main

switch.

2. Tune the receiver to PAL circular pattern.

3. Set brightness and contrast controls to normal.

4. Connect digital V-meter to test point "TP-B".

5. By using VR351, adjust voltage to 150 ± 0.5 V.

AFT ADJUSTMENT

1. B/G/I area : Tune the receiver to the clearest station on

system BG. By using T121, adjust AFT to obtain the best picture.

2. L/L’ area : Tune the receiver to VL station on system L/L’. By

using VC141, adjust AFT to obtain the best picture.

3. If BG/I and L/L’ can be received adjust 1 and 2.

AGC ADJUSTMENT

NOTE:

Do not attempt this adjustment with weak signal.

1. Tune the receiver to the clearest station.

2. Set AGC VR(VR120) in direction which causes snow noise

to appear, then in the opposite direction until snow noise just disappears.

GREY SCALE ADJUSTMENT

[SCREEN VR ADJUSTMENT]

1. Tune the receiver to the white pattern.

2. Set brightness control to display centre and contrast control

to normal.

3. Set SW220 to "SERVICE" position.

4. Set VR602 and VR612 to be mechanical centre.

5. Turn VR601, VR611 and VR621 fully counter-clockwise.

6. Set screen VR for one colour to be just visible.

[BIAS VR ADJUSTMENT]

7. By using VR601, VR611 or VR621, adjust line to be white.

8. Set SW220 to "NORMAL" position.

[DRIVE VR ADJUSTMENT]

9. By using VR602 and VR612, adjust white balance.

HIGH VOLTAGE & WIDTH ADJUSTMENT

[HIGH VOLTAGE ADJUSTMENT]

1. Tune the receiver to PAL circular pattern.

2. Set brightness and contrast controls to maximum.

3. Connect digital V-meter to both terminals of R232(left

side)(+) , and high voltage meter to CRT anode.

4. Confirm high voltage to be 26.0 ± 1 KV at beam current 1.3,

and less than 29.0 KV at 0 beam current .

[H-WIDTH ADJUSTMENT]

5. Adjust VR462 to obtain proper H- width.

6. Reconfirm high voltage.

H-CENTRE ADJUSTMENT

1. Tune the receiver to circular pattern.

2. Adjust H-centre by using VR401.

V-CENTRE ADJUSTMENT

1. Tune the receiver to circular pattern.

2. Adjust V-centre by using SW451.

V-SIZE ADJUSTMENT

1. Tune the receiver to circular pattern.

2. Adjust V-size by using VR451.

FOCUS ADJUSTMENT

By using FOCUS VR, adjust focus control for well scanning lines.

-8-

DC 15V DC 5V AGC voltage (4.3-4.5V) Output probe

Input probe Tool-A System SW Sweep ATT

DETECTOR

ADJUSTMENT - 1

SETTING

IC351-pin 1 Q381-Emitter IC101-pin 48 IC101-pin 45 (Side b) IC101-pin7 IC101-pin46 BG 20

Adjustment

By using T121, adjust "P" to be maximum amplitude.

VIF waveform

CIRCUIT ALIGNMENT

VIF ALIGNMENT

Input probe

Output probe

Tool-A

Detector adjustment - 1

MAIN BOARD

Detector adjustment - 2

VC141

DETECTOR

ADJUSTMENT - 2

IC351-pin 1 Q381-Emitter IC101-pin 48 IC101-pin 45 (Side b) IC101-pin7 IC101-pin46 L’ 20

By using VC141, adjust "P" to be maximum amplitude.

Note: How to select SYSTEM L or L’

1. Before switching on connect IC701 pin 11 to ground.

2. Select L or L’ according to the table.

L L’ IC701- GND SHORT SHORT Q761- GND SHORT OPEN

10kΩ

0.002µF

75Ω

1kΩ

a b

0.01uF

VR351 +B ADJ.

Q702

Q701

IC352

IC351

Q434

451

SIZE

Q431

02 ART T erminal-2

IC451 V-Output

SW451

V-CENTRE

Q820

Q203

Q124

Q202

TP-E

IC270

Q205

1H Delay

Q862 Q861

Q852

Q800

K801

SCART T erminal-1

21P-SCART TERMINAL

Q122

IC101

IF/CHROMA/VIDEO/DEF.

IC280

VR401 H-CENTRE

Q401

IC801

Q853

TV/AV SW.

Q855

Q854

Q856

Q857

T121

Q101

Q851

Q741Q128

TP-D

AUDIO UNIT

VR120 AGC

IC353

TP-A

IC851

A101 TUNER

-9-

DC 12V AGC voltage (DC 5V) Output probe

Input probe Sweep ATT Marker Frequency

System

FM DETECTOR-1

SETTING

KOH - PIN 5 IC002-pin 13 IC002 - PIN 5 (Side a) IC002-pin 17 10

38.9MHz

Adjustment

By using T003, adjust "P"

to be ± 100KHz frequency

VIF waveform

By using T002, adjust DC level to be 1.7V.

FM DETECTOR-2

KOH - PIN 5 IC001 - PIN 21 IC001-PIN 15 (Side b) IC001-pin 16

(Condition)

Carrier frequency: 5.5MHz Modulation frequency: 1kHz(sine waveform)

B/G (See note)

Input probe

Output probe

SIF ALIGNMENT

FM Detector-2

FM Detector-1

AUDIO BOARD

1.7V

By using T001, adjust DC level to be 1.7V.

KOH - PIN 5 IC1001 - PIN 21 IC001-pin 19 (Side b) IC001-pin 18

(Condition)

Carrier frequency: 5.74MHz Modulation frequency: 1kHz(sine waveform)

B/G (See note)

1.7V

103P

NOTE: How to set system B/G * KOH - 1, Connect to 5V * KOH - 2, Connect to

chassis earth.

10kΩ

0.002µF

75Ω

1kΩ

a b

0.01uF

IC101

T001

T002

IC102

T003

DC=0 DC=0

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