Grundig T2S08.pdf

COLOR TELEVISION

SERVICE MANUAL

21” T2S08 CHASSIS

WITH NICAM&TELETEXT

CONTENTS

Ⅰ SAFETY PRECAUTION ………………………………………………… 1

Ⅱ SPECIFICATION ………………………………………………………… 2

Ⅲ IC’S GENERAL DESCRIPTION ……………………………………… 3

Ⅳ SPECIAL IC INTRODUCTION ………………………………………… 3

Ⅴ CHASSIS BLOCK DIAGRAM ………………………………………… 12

Ⅵ SERVICE MODE&ADJUSTMENT …………………………………… 13

Ⅶ TEST POINT WAVE FORM&SCHEMATIC DIAGRAM …………… 18

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Ⅰ SAFETY PRECAUTION

1. X-RAY RADIATION PRECAUTION

1.1 Excessive high voltage can prod u ce potentially hazardous X-RAY RADIATION. To avoid such hazards

the high voltage must be specified limit. The normal value of the high voltage of this receiver is 27KV ±

500V under 230V AC power source. The high voltage must not exceed 30KV.

1.2 Each time a receiver requires servicing the high voltage should be checked following the HIGH

VOLTAGE CHECK procedure in this manual. It is recommended the reading of the high voltage be

recorded as a part of the service record. It is important to use an accurate and reliable high voltage meter.

1.3 The primary source of X -RAY RADIATION in this TV receiver is the picture tube. For continued X-RAY

RADIATION protection, the replacement tube must be exactly the same type tube as used in this TV

receiver.

1.4 Some parts in this receiver have special safety-related characteristics for X-RAY RADIATION protection.

For continued safety, parts replacement should be undertaken only after referring the PRODUCT SAFETY

NOTICE below.

2. GENERAL SAFETY PRECAUTION

The following are the necessary precautions to be observed before servicing this chassis

WARNING: Service should not be attempted by anyone unfamiliar with the necessary

2.1 Since the power supply circuit of this receiver is directly connected to the AC power line. An isolation

transformer should be used during any dynamic service to avoid possible shock hazard.

2.2 Always discharge the picture tube anode to the CRT conductive coating before handling the picture

tube. The picture tube is highly evacuated and if broken, glass fragments will be violently expelled. Use

shatterproof goggles and keep picture tube away from the unprotected body while handling.

2.3 When replacing a chassis in the cabinet, always be certain that all the protective devices are put back

in place, such as: nonmetallic control; knobs, insulating covers, shields, isolation resistor-capacitor,

network, etc.

2.4 Connection wires must be kept away from components with high voltage or high temperature.

2.5 When replacing parts or circuit boards, disconnect the power cord.

2.6 When replacing a high voltage resistor (metal oxide resistor) on circuit board, keep the resistor APP.

10mm (1/2 in.) away from circuit board.

2.7 If any fuse in this TV receiver is broken, replace it with the FUSE specified in the chassis parts list.

2.8 The receiver is designed to operate with 230V (50Hz) AC mains.

3. PRODUCT SAFETY NOTICE

Many electrical and mechanical parts in this chassis have special safety-related characteristics are often

passed unnoticed by a visual inspection and the X-RAY RADIATON protection afforded by them cannot

necessarily be obtained by using replacement components rated for higher voltage. The use of substitute

replacement parts that do not have the same safety characteristics as specified in the parts list may create

shock, fire, X-RAY RADIATION or other hazards.

Warning!

There are no any repairable components in this TV set. Do not try to make any change to it. High voltage

inside may cause danger.

-1-

Ⅱ SPECIFICATION

COLOR SYSTEM: PAL SECAM

SOUND SYSTEM:B/G D/K I NICAM STEREO

RF SYSTEM

VIDEO SYSTEM

PAL SECAM NTSC4.43

TUNING SYSTEM

VOLTAGE SYNTHESIZER TUNING

VHF-L: E2 ～ S6 48.25 MHz ～ 140.25MHz

VHF-H: S7 ～ S36 147.25 MHz ～ 423.25MHz

UHF: S37 ～ DS57 431.25 MHz ～ 863.25MHz

RECEIVING CHANNEL

PROGRAM PRESET

1 SIDE RCA AV IN

1 FULL SCART AND 1 AV SCART

AV JACKS

TELETEXT

1PAGE

ANTENNA INPUT

75Ω （ UNBALANCE ）

AUDIO OUTPUT

≥ 2.5W

MAIN POWER

170-260V AC 50/60Hz

POWER CONSUMPTION

100W

Ⅲ CHIP GENERAL DESCRIPTION

1. MAIN BOARD PART

IC001 ST92195 MCU With ON SCREEN DISPLAY and TELETEXT Decoder

IC002 24C08 8 Kbit Serial I 2 C Bus EEPROM

IC101 STV2246 I²C BUS-Controlled Multistandard Single Chip TV Processor

IC301 STV9306A/B BUS-Controlled VERTICAL DEFLECTION W.E/W CORRECTION CIRCUIT

IC601

H11A817C

OPTOCOUPLERS

IC603

MC7808CT

+8V VOLTAGE REGULATOR

IC604

IC605

MC7805CT

+5V VOLTAGE REGULATOR

IC606

MC7812CT

+12V VOLTAGE REGULATOR

IC701

CD7522CS

3W AUDIO AMPLIFIER

IC801

STV8216

Multi-standard TV Audio Processor and Digital Sound Demodulator

Ⅳ CHIP INTRODUCTION

1. ST92195

The ST92195 microcontrollers are developed and manufactured by STMicroelectronics using a proprietary

n-well HCMOS process. Their performance derives from the use of flexible 256-register programming model

for ultra-fast context switching and real-time event response. The intelligent on-chip peripherals offload the

ST9 core from I/O and data management processing tasks allowing critical application tasks to get the

maximum use of core resources. TheST92195 MCU support low power consumption and low voltage

operation for power-efficient and low-cost embedded systems.

1.1 Main features

28 fully-programmable I/Os

4 channels Analog/Digital Converter

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Built in I 2 C bus interface

Built in OSD and Teletext decoder

14-bit Voltage Synthesis PWM output for VS tuning system

1.2 Pin description

Pin No.

Pin Name

Signal Name

I / O

Function

P2.0

IRIN

IR Input

RESET

Hardware Reset

P0.7

I/O

Not Used

P0.6

MUTE

Mute Output PIN

P0.5

I/O

Not Used

P0.4

ON/OFF

Standby Output

P0.3

DESIGN

Service menu control

P0.2

SCART1

Identify scart entering Design

P0.1

SCART2

Identify scart entering Design

P0.0

AV SEL

AV Selection

P3.7

AV/TV

P3.6

AV/TV

P3.5

TV/DVD

P3.4

DFD

Default data control

OSD Blue colour Signal Output

OSD Green colour Signal Output

OSD Red colour Signal Output

BLANK

OSD Blanking Output

I 2 C data line

P5.1

SDA

I/O

I 2 C clock line

P5.0

SCL

VDD

+5 V Digital Supply

JTDO

Test Pin

WSCF

Analog Pin For VPS / WPP slicer line PLL

WSCR

Analog Pin For VPS / WPP slicer line PLL

AVDD3

+5V Analog VDD For PLL

TEST0

Test Pin

MCFM

Analog Pin for display pixel freq. multiplier

JTCK

Test Pin

TXCF

Analog pin for VPS /WSS line PLL

CVBSO

Test Pin

AVDD2

Analog Power supply

JTMS

Test Pin

CVBS2

CVBS In for VPS / WSS

CVBS1

CVBS In for Teletext Slicer

AGND

Analog ground

GND

Digital ground

JTRST0

Test Pin

PXFM

Analog Pin for display pixel freq. multiplier

AVDD1

Analog Power Supply

HSYNC

Horizontal Sync Input

VSYNC

Vertical Sync Input

-3-

P4.0

BSW1

Band switch 1

P4.1

BSW2

Band switch 2

P4.2

SAW_SW1

SAW Filter switch 1

P4.3

I/O

Not connected

P4.4

SAW_SW2

SAW Filter switch 2

P4.5

I/O

Not connected

P4.6

Vlin PWM

V-linearity PWM output

P4.7

VOL PWM

VOL PWM output

XTAL

Clock oscillator

XTAL

Clock oscillator

P2.5

LED2

LED driver

P2.4

LED1

LED driver

P2.3

VST Voltage ouput

P2.2

I/O

Not connected

P2.1

KB INPUT

KEY Input

1.3 Block diagram

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