Toshiba 28YT56 User manual

SERVICE MANUAL
PRINTED IN UK. 2003 C
COLOURTELEVISION
28YT56/32YT56
TOSHIBA

Service Manual
AK49-001
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TABLE OF CONTENTS
1. INTRODUCTION 4
1.1. Purpose 4
1.2. Scope 4
1.3. General Features 4
2. GENERAL DESCRIPTION 5
2.1. Introduction 5
2.2. System Building Blocks 5
2.2.1. UOC-III (Ultimate-One-Chip) 5
2.2.1.1. Fav & B_Svhs & F_Svhs 8
2.2.1.2. Scart1 8
2.2.1.3. Scart2 8
2.2.1.4. Scart3 9
2.2.1.5. VestelBus 9
2.2.1.6. Audio 9
2.2.1.7. Port Allocations 10
2.2.1.8. Power Management 11
2.2.1.9. Input & Output Performance 12
2.2.1.10. Feature Board 14
2.2.2. Audio Block 15
2.2.2.1. Audio Power Amplifier 15
2.2.2.2. Headphone Amplifier 17
2.2.2.3 Pop Noise Protection Circuit 18
2.2.3. Deflection & Display Block 19
2.2.3.1. Horizontal Deflection 19
2.2.3.2. Vertical Deflection 20
2.2.3.3. CRT Board 22
2.2.3.4. Rotation 23
2.2.3.5. X-RAY Protection 24
2.2.3.6. Dynamic Focus 24
2.2.3.7 Screen & Focus Short Circuit Protection 25
2.2.4. SMPS BLOCK 28
2.2.4.1. Primary Block 28

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2.2.4.2. Secondary Block 29
2.2.5 CABELING 31
2.2.6 CABLE SPECs 33
2.2.6.1 RGB CABLE 33
2.2.6.2 200V CABLE (with BSVM) 35
2.2.6.3 200V CABLE (with BSVM) 37
2.2.7 SAW FILTER 39
2.2.8 TUNER 40
3. AK49 CHASSIS MANUAL ADJUSTMENTS PROCEDURE 41
3.1 SMPS B+ADJUSTMENT 41
3.2 AFC ADJUSTMENT 41
3.3 FOCUS ADJUSTMENT 41
3.4 SCREEN ADJUSTMENT 42
4. AK49 CHASSIS PRODUCTION SERVICE MODE ADJUSTMENTS 43
5. MENU LANGUAGE TABLE 74
6.PICTURE MODES 75
7. CIRCUIT DIAGRAMS 79
8. APPENDIX 84
DVB-T MODUL SERVICE MANUAL

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Document History
Versi
on Date
Document
Revision and
Review
History
Status Prepared by Approved by
v0.1 14.12.2004 Draft YAVUZ İNCE
SERDAR GÜLTEN
KAGAN M. PANCAR
File Name: AK49_SM_VO1

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1. Introduction
1.1. Purpose
This document is prepared for the UOC3 TV project and describes the whole system features and
operating principles to be used in hardware design phase.
The document is based on “Device Specification UOCIII-Version 2.5” and “Introducing UOC-III” from
Philips Semiconductors.
1.2. Scope
The document covers detailed descriptions of AK49 chassis system building blocks.
1.3. General Features
AK49 is a 110°/ 50 Hz. chassis which is capable of driving CRT sizes in the range of 24” – 33”,
including realflat and 16:9 CRT’s . The chassis has the following main features;
•Remote Control
•Colour Standards ; PAL, SECAM, NTSC,
•Transmission standards ; B/G, L/L’ I/I’, DK,
•Teletex ; 10 pages,
•Intercarier/QSS sound proccessing,
•Multi-standard alignment free PLL tuning,
•PIP, PAP, POP, PAT, TAT ,
•CTI option ,
•2D Comb Filter ,2D/4H
•Headphone with volume control,
•SubWoofer option,
•2 Full Scart with SVHS availability via Scart-2 , Scart-3 / BAV, FAV and F_SVHS /B_SVHS,
•BSVM option,
•Dynamic Focus option,
•Rotation (Tilt) option,
•NICAM/GERMAN Stereo,
•Virtual Dolby option,
•2 x 10W (%10 THD),
•YPbPr input feature,
•TV-DVD Combi ,
•IDTV ,
•TV-R/HDD,
•EPG,

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2. General Description
2.1. Introduction
This chapter describes system building blocks and their detailed discriptions.
2.2. System Building Blocks
AK49 chassis main block are;
•UOC3 : Microcontroller + Video Proccessor + Sound Proccessor + IF+Teletext
•SMPS : SMPS Controller, SMT, Bridge Rect., Line Filters
•HV Block : FBT, HOT, Vertical Amplifier, Line Driver, EW Amp.
•AUDIO : Audio Amp., DAC, Comperator.
•CRT BOARD : RGB Amp.
•Feature Board : PIP, CTI IC’s.
2.2.2 UOC-III (ULTIMATE-ONE-CHIP)
UOC3 is composed of microcontroller, video proccessor, sound proccessor and IF blocks. So, there
are digital and anolog parts in it named as Picasso and Cosmic respectively as shown below ;
UOC3 has standard and face down versions, pin squence differs between two version. After
investigation of the pining it is decided to use face down version for layout compability.

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Block diagram of the TV System with face-down version is;

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?

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2.2.2.1 FAV & BAV & B_SVHS & F_SVHS
B_SVHS and F_SVHS inputs can not be supported at the same time.
FAV & B_SVHS_Y & F_SVHS_Y inputs use same CVBS input. (cvbs2/74)
B_SVHS_ C & F_SVHS_C input is C2/C3(70).
FAV audio input is AUDIOin_5 L,R (94,95) and shared with F_SVHS.
BAV video input is CVBS1 (81) and can not be supported with SCART3 at the same time.
BAV audio input is AUDIOin_4 L,R (80,79) and shared with SCART3.
2.2.2.2 SCART1
SCART1 video input is (CVBS3/71) . SCART1 video input is also applied to Video Switch
IC(TEA6415C) for PIP application.
SCART1 video out will use (IFVO/86) front_end video output, that output is also used as SCART3
video output via a buffer circuit.
SCART1 RGB/fblk inputs are R(51), G(50), B(49), FBLK(52) .
SCART1 AUDIO input is AUDIOin_3 L,R ( 73,72) .
SCART1 AUDIO output is AUDIOout_SR,SL (93,92). Same output also used as SCART3 Audio output.
2.2.2.3 SCART2
SCART2 video input is CVBS4 (78) . SCART2 video input is also applied to Video Switch IC(TEA6415C)
for PIP application.
SCART2 supports SVHS input. SVHS / C input is C4 (77) , Y input is use same video input.
SCART2 video output is CVBSO/PIP (65). That video output is selectable, all inputs can be selected to
be output from SCART2.
SCART2 RGB inputs are R(59), G(57), B(58), FBLK/INSSW2 (54), except CTI/PIP option.
At PIP application ;
-There are PIP_CVBS, SCART1, SACRT2, SCART3, FAV video inputs and RGB, FBLK inputs to PIP IC.
-If there is no CTI application, PIP output is applied to SCART2 RGB input directly.
-In case of PIP&CTI combined application, PIP output will be input to CTI IC as YUV. The YUV
output of CTI IC will be applied to R/Vin(59), G/Yin(57), B/Uin(58) as YUV.

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©Copyright 2003 VESTEL Group of Company
All rights reserved. Passing on and copying of this document, use and communication of its contents not permitted without written permission from VESTEL
YPbPr input is possible via SCART2 RGB lines with an adaptor.
In this case R/Vin(59), G/Yin(57), B/Uin(58) inputs can be used as;
-RGB,
-YUV,
-YPbPr inputs.
SCART2 audio inputs are AUDIOin_2 L,R ( 75) .
SCART2 audio outputs are AUDIOout_HPR,HPL (67,66). That output is also selectable .
2.2.2.4 SCART3
SCART3 video input is CVBS1 (81) . That input will also be used as optional BAV video input. and
applied to Video Switch IC(TEA6415C) for PIP application.
SCART3 video output will be SCART1 video output via a buffer circuit.
SCART3 audio inputs are AUDIOin_4 L,R (80,79). These audio inputs will also used for optional BAV
L,R and VESTELBUS L,R audio inputs.
SCART3 audio out will be through SCART1 audio outputs via a buffer circuit.
2.2.2.5 VESTELBUS(IDTV,DVD-Combi)
VESTELBUS video input is CVBS1 (81), so VESTELBUS will not be supported with SCART3 at the same
time.
VESTELBUS RGB inputs are SCART2 RGB inputs, so in case of VESTELBUS option SCART2 RGB
is not supported.
VESTELBUS UART input ;
- TXD TX (1),
- RXD RX (2),
- IRQ_DVB INT2 (3).
VESTELBUS I2C input is standard I2C bus.
2.2.2.6 AUDIO
Main audio out is AUDIOout_LSR,LSL (69,68).
Selectable HP out is I2SD01 24) out to DAC.
Subwoofer out is I2SD02 (25) out to DAC.

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2.2.2.7 PORT ALLOCATIONS
(32) (INT-0) REMOTE
(31) (INT-1) TV_LINK
(30) (Counter-Timer) PROTECTION
(27) (I2S Word Select) I2S_WS
(26) (I2S Clock) I2S_CLK
(25) (I2S OUT2) I2S_Swoofer
(24) (I2S OUT1) I2S_HP
(23) (I2S-IN/OUT) WRITE-PROT.
(22) (ON/OFF) ON/OFF+LED
(21) (SCL) SCL
(20) (SDA) SDA
(18) (PWM) ROT/TILT
(17) (PWM0) PAP_LOW
(16) (PWM1) SW
(15) (PWM2) S_RESET
(14) (ADC0) AV1_STAT
(13) (ADC1) AV2_STAT
(10) (ADC2) AV3_STAT/DVD SENSE
(9) (ADC3) KEYB.+SERV.
(7) (PWM3) MUTE
(6) (PWM4) SAW_SW
(3) (INT2) IRQ/DVB
(2) (UARTBUS) RXD
(1) (UART BUS) TXD

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2.2.2.8 POWER MANAGEMENT
The power consumption of UOC3 is ;
Only 3,3V_Stb is necessary for the start-up. IC internally produces 2,5V and 1,8V at the Standby
mode. After start-up necessary 1,8V are produced by external regulators. So, we have 3,3V_Stb, 5V,
5V_Stb and 1,8V. for UOC3. We don’t have 8V. even for audio outputs (1,2V RMS achieved with 5V).
All the voltages are produced by SMPS except 1,8V.
RESET :
1V8 digital and 1V8 analogue are produced by using 2V5 DECDIG-signal. DECDIG-signal is given

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to base of Q108 Transistor and base of Q114 Transistor. The collector voltage becomes 1v8.
When the +3V3_stb voltage decreases below the 2V6 Q110 Transistor goes OFF condition so FETs
become ON. Q107 FET shorts 1V8 digital to ground and system is reset condition.
Another reset condition becomes when the S_Reset port is active. While S_Reset port is active, FETs
become ON. 1V8 digital is shorted to ground.
All the supply architecture of the UOC3 is as follows;

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2.2.2.9 INPUT & OUTPUT PERFORMANCE
EXTERNAL INPUT - OUTPUT PERFORMANCE
CVBS INPUT VOLTAGE 1 ±0.15 Vp_p
CVBS OUTPUT VOLTAGE
Luminance 700 ± 15 % mVpp
Sync 300 ± 15 % mVpp
Burst 300 ± 15 % mVpp
DC level 2 V dc
VIDEO OUTPUT IMPEDANCE 75 ± 10 % Ω
RGB INPUT VOLTAGE 1 ±15 % Vp_p
AUDIO INPUT VOLTAGE 500 ±15 % Mvrms
AUDIO OUTPUT VOLTAGE 500 ±15 % mVrms
AUDIO INPUT IMPEDANCE minimum 10 KΩ
AUDIO OUTPUT IMPEDANCE maximum 1 KΩ
PIN 8 SWITCHING Standard
PRIORITY BETWEEN SCARTS Vestel Standard
RECEPTION PERFORMANCE
USABLE MINIMUM SIGNAL LEVEL 50 dBµV
USABLE MAXIMUM SIGNAL LEVEL 90 dBµV
COLOUR KILLER LEVEL 32 dBµV
SOUND KILLER LEVEL 30 dBµV
SYNCHRONISING SENSITIVITY LEVEL 35 dBµV
FM GERMAN STEREO SENSITIVITY LEVEL 40 dBµV
NICAM STEREO SENSITIVITY LEVEL 40 dBµV
BTSC STEREO SENSITIVITY LEVEL NO BTSC
NOISE LIMITED SENSITIVITY LEVEL 30 dBµV
TELETEXT EYEHEIGHT LEVEL % 45
CLOSED CAPTION SENSITIVITY LEVEL NO CLOSED CAPTION
AFC PULL IN RANGE -500 KHz / +800 KHz
TUNER RECEIVING RANGE ± 5 MHz

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2.2.2.10 FEATURE BOARD ( PIP & CTI )
PIP&PAP and CTI applications performed with that feature board. For PIP&PAP application Micronas
SDA9488/SDA9489 and for CTI application Toshiba TA1366FG is used.
There is a socket on the board for external YUV input which will be used for DVD or IDTV application
with PIP&PAP and CTI feature. There are switches on the board for adaptation of application
configurations.
Only CTI Application
YUV output from UOC3 comes to CTI IC TA1366FG and goes back to UOC3 .
CTI & IDTV or DVD
CTI & PIP Application
YUV output from UOC3 comes to CTI IC TA1366FG , then inputs to PIP IC SDA9488. Any desired
external CVBS signal is directed to PIP IC via video switch and used for PIP picture on CTI applied
video signal. That video signal goes back to UOC3 as YUV.

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2.2.3 AUDIO BLOCK
2.2.3.1 AUDIO AMPLIFIER
TDA8928J 2X10W class D amplifier is used for audio amplification. It is supplied by +14V and –14V to
give 2X10W output to 8ohm. loads by %10 THD.

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Audio inputs Main_L and Main_R is applied via voltage comparator LM393 to amplifier. PWM
swicthing outputs are then filtered by 33UH and 470NF.
SOUND PERFORMANCE
SOUND CALL UP TIME Max. 4 sec.
MAXIMUM AUDIO OTPUT POWER (RF INPUT) 10W
MAXIMUM AUDIO OTPUT POWER (EXTERNAL INPUT) 10W
THD AT MAXIMUM AUDIO OUTPUT POWER (RF INPUT) %10
THD AT MAXIMUM AUDIO OUTPUT POWER (EXTERNAL INPUT) %10
THD AT 50 mW AUDIO OUTPUT POWER (RF INPUT) %3 (IC spec.)
THD AT 50 mW AUDIO OUTPUT POWER (EXTERNAL INPUT) %3 (IC spec.)
SIGNAL TO NOISE RATIO (RF INPUT) 50 db.
SIGNAL TO NOISE RATIO (EXTERNAL INPUT) 40 dB
SIGNAL TO BUZZ RATIO 40 dB
CROSSTALK: TV TO AV - AV TO TV 60 dB
RESIDUAL SOUND (RF INPUT) 20 mW/rms
RESIDUAL SOUND (EXTERNAL INPUT) 20 mW/rms
FREQUENCY RESPONSE (RF INPUT) 100 Hz – 10 kHz
FREQUENCY RESPONSE (EXTERNAL INPUT) 100 Hz – 10 kHz
BASS FREQUENCY RESPONSE (RF INPUT) 10 ± 2 dB
BASS FREQUENCY RESPONSE (EXTERNAL INPUT) 10 ± 2 dB
TREBLE FREQUENCY RESPONSE (RF INPUT) 10 ± 2 dB
TREBLE FREQUENCY RESPONSE (EXTERNAL INPUT) 10 ± 2 dB
POP NOISE 5 Vpp
HORIZONTAL HUM NOISE 15 mVrms
VERTICAL HUM NOISE 15 mVrms
VIDEO NOISE ON THE AUDIO OUTPUT 50 mVpp

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2.2.3.2 HEADPHONE AMPLIFIER
Headphone output is achieved by I2S out. I2S output is converted to anolog signal by DAC
CS4334 and then applied to TDA1308T amplifier.
SubWoofer output is achieved by the same way, I2S ouptut is converted to analog signal by DAC
CS4334 and applied to external SubWoofer amplifier board.DAC CS4334 will work at a rate of 32Fs
MCLK/LRCK = 512, 256 or 128 and De-emphasis feature of CS4334 is disabled.
HEADPHONE PERFORMANCE
MAXIMUM AUDIO OUTPUT POWER (RF INPUT) 22,5 ± 2,5 mWrms
MAXIMUM AUDIO OUTPUT POWER (EXTERNAL INPUT) 22,5 ± 2,5 mWrms
THD AT MAXIMUM AUDIO OUTPUT POWER (RF INPUT) %10
THD AT MAXIMUM AUDIO OUTPUT POWER (EXTERNAL INPUT) %10
THD AT 0.5 mW AUDIO OUTPUT POWER (RF INPUT) %1
THD AT 0.5 mW AUDIO OUTPUT POWER (EXTERNAL INPUT) %1
SIGNAL TO NOISE RATIO (RF INPUT) 40 dB
SIGNAL TO NOISE RATIO (EXTERNAL INPUT) 40 dB

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2.2.2.3 POP NOISE PROTECTION CIRCUIT
This circuit is used to prevent pop noise in AC turn-off. While TV is working due to +14V. T1
is OFF . In turn-0ff situation BE voltage of T1 becomes negative and transistor goes to ON
condition ,so it drives T2 and T2 pull-down mute pin to perform muting.

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2.2.3 DEFLECTION & DISPLAY BLOCK
2.2.3.1 Horizontal Deflection
Deflection block consist of following main parts,
Horizontal driver transistor (Q601),
Horizontal driver (TR600),
HOT (Horizontal Output Transistor) (Q600),
FBT (TR601),
E/W transistor (Q602),
E/W coil (L601),
E/W injection Coil (Bridge Coil) (L602),
Linearity Coil (L603),
Flyback Capacitors (C608, C607),
S-correction capacitor (C615 ve C613),
Modulated S-correction capacitor (C611),
Hdrive signal is buffered and applied to line driver transistor by a capacitor.
Line driver produces necessary base currents, parallel diode to base series resistor speeds up the
reverse base current.
UOC3 has soft-start and soft-stop features to have more safe operation. There are two base current
adjustment resistors on the circuit. Collector current differs according to CRT sizes .
Tube dependent components are choosen to fit best picture performance by keeping;
11,5 usec. Flyback time,
Max. 1300V. collector voltage (peak-detect mode measurement)
Max. 500V. at the diode modulator cathode (D605).
Max. 20V. (peak-detect mode measurement) at the E/W transistor drain.
Max. 200V video B+ voltage.