21LF-90H (serv.man3) - Sharp TV Service Manual (repair manual)

 PAL 

B/G, I

 / SECAM 

L/L’, B/G, D/K  

SYSTEM COLOUR TELEVISION

In the interests of user safety (required by safety
regulations in some countries) the set should be re-
stored to its original condition and only parts identi-
cal to those specified should be used.

CONTENTS

TABLE OF CONTENTS ....................................................................................................... 3
INTRODUCTION .................................................................................................................. 6
CIRCUIT DESCRIPTIONS ................................................................................................... 6
INTEGRATED CIRCUIT DESCRIPTIONS ....................................................................... 13
BLOCK DIAGRAM ................................................................................................................ 22
SERVICE MODE ADJUSTMENTS ...................................................................................... 23
HOTEL MODE FUNCTIONS ................................................................................................  30
CIRCUIT DIAGRAMS ..................................................................................................... 31
HOW TO UPDATE THE TECHNICAL INFORMATION ...................................................... 41

SE

00

AK44CHA00

               Issued: 9

th

 March 2004

Use this page to keep any special servicing information as Technical Report (Bulletin), Technical Information, etc.
If only part  number changes are required, just change part number directly the part number in the Parts Listing Section.
If you need more information, please refer to the Technical Report (Bulletin).

SAFETY PRECAUTIONS ............................................................................................................................................... 5

TV set switched off ............................................................................................................................................... .....5
Measurements ....................................................................................................................................................... 5

PERI-TV SOCKET ........................................................................................................................................................... 5
SCART 1........................................................................................................................................................................... 5

1. INTRODUCTION ......................................................................................................................................................... 6

CIRCUIT DESCRIPTIONS ............................................................................................................................................. 6
2. SMALL SIGNAL PART WITH STV2248 ..................................................................................................................... 6

2.1 Vision IF amplifier ........................................................................................................................................... 6
2.2 QSS Sound circuit (QSS versions) ................................................................................................................. 6
2.3  AM Demodulator ........................................................................................................................................... 6
2.4 FM demodulator and audio amplifier (mono versions) .................................................................................. 6
2.5 Video switch ................................................................................................................................................... 6
2.6 Synchronisation circuit  .........................................................................................................................................6
2.7 Chroma and luminance processing ................................................................................................................ 7
2.8 RGB output circuit .......................................................................................................................................... 7
2.9 µ-Controller .................................................................................................................................................... 8

2.9.1 Controls .............................................................................................................................................. 8
2.9 .2 Teletext ............................................................................................................................................. 8

2.10 Video Path ..................................................................................................................................................... 9
2.11 Sound Path  .................................................................................................................................................. 9
2.12 AV Input Signal Path ..................................................................................................................................... 9

2.12.1 Video and Sound  ............................................................................................................................ 9
2.12.2  RGB ................................................................................................................................................ 9

3. TUNER ....................................................................................................................................................................... 9

4. DIGITAL TV SOUND PROCESSOR MSP34X0 ........................................................................................................ 10
5. SOUND OUTPUT STAGE TDA7266L/TDA7266 ...................................................................................................... 10
6. VERTICAL OUTPUT STAGE WITH TDA8174A ....................................................................................................... 10
7. VIDEO OUTPUT AMPLIFIER TDA6107 ................................................................................................................... 11
8. POWER SUPPLY (SMPS) .......................................................................................................................................... 11

8.1 Start Up ......................................................................................................................................................... 11
8.2 Voltage Regulation .......................................................................................................................................... 11
8.3 Voltage Protection .......................................................................................................................................... 11
8.4 Current Regulation .......................................................................................................................................... 11
8.5 Standby operation .......................................................................................................................................... 12
8.6 Mode transition ............................................................................................................................................. 12
8.7 SMPS Switch Off  .......................................................................................................................................... 12

9. LINE CIRCUIT ............................................................................................................................................................ 12

9.1 B.C.L. Circuit (Beam Current Limiter)  ........................................................................................................... 13

10. SERIAL ACCESS CMOS 8K EEPROM 24C08 ...................................................................................................... 13
11. SAW FILTERS .......................................................................................................................................................... 13

12. IC DESCRIPTIONS AND INTERNAL BLOCK DIAGRAM ..................................................................................... 13

ST92195 ................................................................................................................................................................ 14
STV224X ............................................................................................................................................................... 15
UV1315, UV1316, UV1336 .................................................................................................................................. 15
TDA7266/TDA7266L .......................................................................................................................................... 17
TDA8174 ..................................................................................................................................................................18
TDA6107 ................................................................................................................................................................ 18
MC44608 .................................................................................................................................................................19
MSP34X0G ..............................................................................................................................................................19
24C08 .................................................................................................................................................................... 20

TDA1308 ................................................................................................................................................................ 21
SAW FILTERS ....................................................................................................................................................... 21

13. GENERAL BLOCK DIAGRAM of 11AK44 ..................................................................................................................22

14. SERVICE MENU ...................................................................................................................................................... 23

14.1 Service Menu entrance ................................................................................................................................ 23
14.2 Service Adjustments ................................................................................................................................... 23
14.3 Using Coloured Buttons .............................................................................................................................. 24

14.3.1 AVL  ............................................................................................................................................... 24
14.3.2 Geometry Menu  ............................................................................................................................. 25

14.3.2.1 Geometry Table  ................................................................................................................ 25
14.3.2.1 Geometry Table  ................................................................................................................ 25

14.3.3 Screen Adjustment   ...................................................................................................................... 26
14.3.4 IF Adjustment ................................................................................................................................ 26

14.4 Auto Programming System Set Up ............................................................................................................. 25

15. OPTIONS ................................................................................................................................................................... 27

15.1 Service Registers updating regarding the Tuner   ...................................................................................... 27
15.2 Registers details ......................................................................................................................................... 28

16. LANGUAGES ......................................................................................................................................................... 30
17. HOTEL MODE FUNCTIONS ................................................................................................................................... 30
18. SCHEMATIC DIAGRAMS ........................................................................................................................................ 31
19. HOW TO UPDATE THE TECHNICAL INFORMATION  ........................................................................................ 41