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Sylvania SST4274S Service Manual

27" color television
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SERVICE MANUAL
27" COLOR TELEVISION
SST4274S

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Summary of Contents for Sylvania SST4274S

  • Page 1 SERVICE MANUAL 27" COLOR TELEVISION SST4274S...

  • Page 2: Table Of Contents

    IMPORTANT SAFETY NOTICE Proper service and repair is important to the safe, reliable operation of all Funai Equipment. The service procedures recommended by Funai and de- scribed in this service manual are effective methods of performing service operations. Some of these service special tools should be used when and as recommended.

  • Page 3: Specifications

    SPECIFICATIONS <TUNER> ANT. Input ------------------- 75ohm Unbal., F type Reference Level ----------- 20Vp-p (CRT Green Cathode) Test Input Signal ---------- 400Hz 30% modulation Description Condition Unit Nominal Limit 1. Intermediate Freq. Picture 45.75 Sound 41.25 2. Peak Picture Sens dBµv CATV dBµv dBµv...

  • Page 4: Important Safety Precautions

    IMPORTANT SAFETY PRECAUTIONS Prior to shipment from the factory, our products are strictly inspected for recognized product safety and electrical codes of the countries in which they are to be sold. However, in order to maintain such compliance, it is equally important to implement the following precautions when a set is being serviced.
  • Page 5 ing is performed that involves B+, horizontal de- earth ground. If a voltage reading in excess of 1.0V flection or high voltage. Correct operation of the X- is obtained, remove and reinsert the AC power radiation protection circuits also must be recon- plug in the opposite polarity and again measure firmed each time they are serviced.
  • Page 6 Precautions during Servicing 3) Align the lengths of the wires to be connected. In- sert the wires fully into the connector. A. Parts identified by the ( # ) symbol are critical for 4) Use the crimping tool to crimp the metal sleeve at safety.
  • Page 7 Safety Check after Servicing Examine the area surrounding the repaired location Chassis or Secondary Conductor for damage or deterioration. Observe that screws, parts and wires have been returned to original posi- tions. Afterwards, perform the following tests and con- Primary Circuit Terminals firm the specified values in order to verify compliance with safety standards.

  • Page 8: Standard Notes For Servicing

    STANDARD NOTES FOR SERVICING Circuit Board Indications How to Remove / Install Flat Pack-IC a. The output pin of the 3 pin Regulator ICs is indicat- 1. Removal ed as shown. With Hot-Air Flat Pack-IC Desoldering Machine: (1) Prepare the hot-air flat pack-IC desoldering ma- Top View Bottom View chine, then apply hot air to the Flat Pack-IC (about...
  • Page 9 3. The flat pack-IC on the CBA is affixed with glue, so With Soldering Iron: be careful not to break or damage the foil of each (1) Using desoldering braid, remove the solder from pin or the solder lands under the IC when remov- all pins of the flat pack-IC.
  • Page 10 2. Installation (4) Bottom of the flat pack-IC is fixed with glue to the CBA; when removing entire flat pack-IC, first apply (1) Using desoldering braid, remove the solder from soldering iron to center of the flat pack-IC and heat the foil of each pin of the flat pack-IC on the CBA up.
  • Page 11 Instructions for Handling Semiconductors Electrostatic breakdown of the semiconductors may occur due to a potential difference caused by electro- static charge during unpacking or repair work. 1. Ground for Human Body Be sure to wear a grounding band (1MΩ) that is prop- erly grounded to remove any static electricity that may be charged on the body.

  • Page 12: Cabinet Disassembly Instructions

    CABINET DISASSEMBLY INSTRUCTIONS 1. Disassembly Flowchart Note : (1) Order of steps in procedure. When reassembling, This flowchart indicates the disassembly steps for the follow the steps in reverse order. These numbers cabinet parts, and the CBA in order to gain access to are also used as the Identification (location) No.
  • Page 13 [3] Main CBA [1] Rear Cabinet Fig. 1 Fig. 3 [2] CRT CBA Anode Cap [1] Rear Cabinet [4] CRT Fig. 2 Fig. 4 L2712DC...
  • Page 14 TV Cable Wiring Diagram DG691 DEGAUSSING COIL SP802 SP801 MAIN CBA CLN802 CLN801 CN802 CN801 CN691 WH301A TU11 FLYBACK TUNER TRANSFORMER CN571 T571 WH501A TO CRT GROUND AC601 WH501B AC CORD CN1501 FOCUS JK1501 SCREEN WH301B ANODE Fig. 5 L2712DC...

  • Page 15: Electrical Adjustment Instructions

    ELECTRICAL ADJUSTMENT INSTRUCTIONS How to set up the service mode: General Note: "CBA" is abbreviation for "Circuit Board Assem- Service mode: bly." 1. Use the service remote control unit. NOTE: 2. Turn the power on. (Use main power on the TV Electrical adjustments are required after replacing unit.) circuit components and certain mechanical parts.
  • Page 16 2. Initial Setting 1. Press "MENU" button on the service remote con- General trol unit. Then select "COLOR" (CLR) display. 1. Enter the Service mode. (See page 5-1) 2. Press "CH o/p" buttons on the service remote 2. Press "VOL p" button on the service remote control control unit so that the value of "COLOR"...
  • Page 17 4. H f Adjustment 7. SD Check Mode 1. Enter the Service mode. (See page 5-1) Purpose: To get correct horizontal frequency. 2. Press "1" button on the remote control unit. The Use service remote control unit. unit enter the SD-Check mode. 1.
  • Page 18 8. H. Position Adjustment 10. V. Position Adjustment Purpose: To obtain correct horizontal position of Purpose: To obtain correct vertical width of screen image. screen image. Symptom of misadjustment: If V. Position is incor- Symptom of Misadjustment: If H. Position is incor- rect, vertical height of image on the screen may not be rect, horizontal position of image on the screen may properly displayed.
  • Page 19 13. PIN Cushion Adjustment 14. Cut-off Adjustment Purpose: To adjust the beam current of R, G, B, and Purpose: To obtain correct straight vertical line of screen voltage. screen image. Symptom of Misadjustment: If H.Pin cushion is incor- Symptom of Misadjustment: White color may be reddish, greenish or bluish.
  • Page 20 15. White Balance Adjustment 16. Sub-Brightness Adjustment Purpose: To mix red, green and blue beams correctly Purpose: To get proper brightness. for pure white. Symptom of Misadjustment: If Sub-Brightness is Symptom of Misadjustment: White becomes bluish incorrect, proper brightness cannot be obtained by or reddish.
  • Page 21 19. Convergence Adjustment The following adjustments normally are not attempted in the field. Only when replacing the Purpose: To obtain proper convergence of red, green CRT then adjust as a preparation. and blue beams. 18. Purity Adjustment Symptom of Misadjustment: If Convergence Adjust- ment is incorrect, the edge of white letters may have Purpose: To obtain pure color.

  • Page 22: Block Diagrams

    BLOCK DIAGRAMS System Control Block Diagram L2712BLS...
  • Page 23 IF/Video Block Diagram L2712BLIF...
  • Page 24 Audio Block Diagram L2712BLA...
  • Page 25 CRT/H.V. Block Diagram L2712BLCRT...
  • Page 26 Power Supply Block Diagram L2712BLP...

  • Page 27: Schematic Diagrams / Cba's And Test Points

    SCHEMATIC DIAGRAMS / CBA'S AND TEST POINTS Standard Notes Many electrical and mechanical parts in this chassis have special characteristics. These characteristics often pass unnoticed and the protection afforded by them cannot necessarily be obtained by using replacement compo- nents rated for higher voltage, wattage, etc. Replacement parts that have these special safety characteristics are identified in this manual and its supplements;...
  • Page 28 LIST OF CAUTION, NOTES, AND SYMBOLS USED IN THE SCHEMATIC DIAGRAMS ON THE FOLLOWING PAGES: 1. CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE, REPLACE ONLY WITH SAME TYPE_A,_V FUSE. ATTENTION: UTILISER UN FUSIBLE DE RECHANGE DE MÊME TYPE DE_A,_V. 2.
  • Page 29 Main 1/4 Schematic Diagram VIDEO SIGNAL MAIN 1/4 Ref No. Position IC111 IC151 TRANSISTORS Q111 Q131 Q161 Q321 Q361 L2712SCM1...
  • Page 30 Main 2/4 Schematic Diagram VIDEO SIGNAL AUDIO SIGNAL MAIN 2/4 Ref No. Position IC431 IC771 IC801 TRANSISTORS Q801 Q811 CONNECTORS CN801 CN802 L2712SCM2...
  • Page 31 Main 3/4 Schematic Diagram CAUTION ! IF SIGNAL Fixed voltage ( or Auto voltage selectable ) power supply circuit is used in this unit. CAUTION: FOR CONTINUED PROTECTION AGAINST RISK NOTE : VIDEO SIGNAL If Main Fuse (F601) is blown, check to see that all components in the power supply OF FIRE, REPLACE ONLY WITH SAME TYPE 4A, 125V FUSE.
  • Page 32 Main 4/4 & CRT Schematic Diagram MAIN 4/4 Ref No. Position Ref No. Position Ref No. Position TRANSISTORS CONNECTORS Q1511 IC551 CN571 TRANSISTORS WH301A Q1521 Q511 WH501A Q1531 CONNECTORS Q512 TEST POINTS Q547 TP591 CN1501 WH301B Q551 TP592 Q552 WH501B TP601 Q561 VARIABLE RESISTORS...
  • Page 33 Main CBA Top View CAUTION ! CAUTION: FOR CONTINUED PROTECTION AGAINST RISK BECAUSE A HOT CHASSIS GROUND IS PRESENT IN THE POWER Fixed voltage ( or Auto voltage selectable ) power supply circuit is used in this unit. OF FIRE, REPLACE ONLY WITH SAME TYPE 4A, 125V FUSE. SUPPLY CIRCUIT, AN ISOLATION TRANSFORMER MUST BE USED.
  • Page 34 Main CBA Bottom View CAUTION: FOR CONTINUED PROTECTION AGAINST RISK BECAUSE A HOT CHASSIS GROUND IS PRESENT IN THE POWER CAUTION ! OF FIRE, REPLACE ONLY WITH SAME TYPE 4A, 125V FUSE. Fixed voltage ( or Auto voltage selectable ) power supply circuit is used in this unit. SUPPLY CIRCUIT, AN ISOLATION TRANSFORMER MUST BE USED.
  • Page 35 CRT CBA Top View CRT CBA Bottom View CRT CBA Ref No. Position TRANSISTORS Q1511 Q1521 Q1531 CONNECTORS CN1501 WH301B WH501B WF14 WF15 Q1521 Q1521 Q1511 Q1511 Collector Base Collector Base Q1531 Base WF13 Q1531 Collector 7-15 7-16 BL2700F01012-2...

  • Page 36: Waveforms

    WAVEFORMS WF1 ~ WF16 = Waveforms to be observed at Waveform check points. (Shown in Schematic Diagram.) Input: NTSC Color Bar Signal (with 1kHz Audio Signal) INITIAL POSITION: Unplug unit from AC outlet for at least 5 minutes. reconnect to AC outlet and then turn power on. (Brightness---Center Color---Center Tint --- Center Contrast---Approx 70%) 1DIV: 2V 20µs 1DIV: 0.5V 20µs...
  • Page 37 WF1 ~ WF16 = Waveforms to be observed at Waveform check points. (Shown in Schematic Diagram.) Input: NTSC Color Bar Signal (with 1kHz Audio Signal) INITIAL POSITION: Unplug unit from AC outlet for at least 5 minutes. reconnect to AC outlet and then turn power on. (Brightness---Center Color---Center Tint --- Center Contrast---Approx 70%) 1DIV: 200V 20µs WF13...

  • Page 38: Wiring Diagram

    WIRING DIAGRAM CN801 CLN801 1 SP-L SP801 SP-GND SPEAKER L-CH CN802 CLN802 1 SP-R SP802 SP-GND SPEAKER R-CH ANODE TU11 TUNER UNIT V501 MAIN CBA BL2700F01012-1 CN691 FOCUS CN1501 T571 SCREEN WH301B WH301A CLN301 BLUE BLUE GREEN GREEN WH501B WH501A CLN501 CRT CBA HEATER 3...

  • Page 39: Ic Pin Functions

    IC PIN FUNCTIONS IC111 (TV Micro Controller) Signal Name Function Signal Name Function 35 N.U. Not Used 36 N.U. Not Used CNVSS 37 V RAMP F/B V Ramp Feed Back N.U. Not Used 38 V RAMP OUT Vertical Output N.U. Not Used 39 V RAMP CAP V Ramp OSC Capacitor...
  • Page 40 Signal Name Function 71 MONO-OUT MONO-OUT White Balance Adjustment 72 I2C OPEN Judgement 73 AFT-IN AFT Voltage Input 74 DG-ON-H Degaussing Coil Control 75 AGC AGC Voltage Input 76 PROTECT 3 Power Supply Protection 77 N.U. Not Used 78 N.U. Not Used 79 P-ON-H Output for P-ON-H...
  • Page 41 EXPLODED VIEWS Cabinet SHINWHA TAPE SGT-730 V501-1 (BLACK) V501-2 Details for DY551 and surrounding parts SHINWHA TAPE SGT-730 DY551 (WHITE) Scotch Tape #880 CLN801 DG691 CLN551 DY551 SP801 CRT CBA Scotch Tape #880 CLN802 V501 SP802 AC601 See Electrical Parts List MAIN CBA for parts with this mark.
  • Page 42 Packing TAPE PACKING TAPE 11-3 L2712PEX...

  • Page 43: Mechanical Parts List

    MECHANICAL PARTS LIST PRODUCT SAFETY NOTE: Products marked with a # Ref. No. Description Part No. have special characteristics important to safety. Before Note: replacing any of these components, read carefully the 1. V501 (CRT) HAS COUPLE OF SUBSTITUTIONAL PARTS AND EACH PARTS ALSO HAS MATCHING COMBINATION WITH DY551.
  • Page 44 CRT Warning Label Location CRT Type No. CRT Warning Label 20040310 12-2 L2712CA...

  • Page 45: Electrical Parts List

    ELECTRICAL PARTS LIST PRODUCT SAFETY NOTE: Products marked with a Ref. No. Description Part No. # have special characteristics important to safety. FILM CAP .(P) 0.047µF/50V J CA1J473MS029 Before replacing any of these components, read care- FILM CAP .(P) 0.033µF/50V J or CMA1JJS00333 fully the product safety notice in this service manual.
  • Page 46 Ref. No. Description Part No. Ref. No. Description Part No. ELECTROLYTIC CAP . 1µF/50V M or CE1JMASDL1R0 ELECTROLYTIC CAP . 1000µF/35V M or CE1GMZNDL102 ELECTROLYTIC CAP . 1µF/50V M or CE1JMASDL010 ELECTROLYTIC CAP . 1000µF/35V M CE1GMZPDL102 ELECTROLYTIC CAP . 1µF/50V M CE1JMASTL010 C506 ELECTROLYTIC CAP .
  • Page 47 Ref. No. Description Part No. Ref. No. Description Part No. CERAMIC CAP . E Z 0.01µF/500V CCD2JZP0E103 ELECTROLYTIC CAP . 100µF/10V M CE1AMASDL101 C606 CERAMIC CAP . F Z 0.01µF/500V or CCD2JZP0F103 C705 CERAMIC CAP .(AX) X K 3900pF/16V CDA1CKT0X392 CERAMIC CAP .
  • Page 48 Ref. No. Description Part No. Ref. No. Description Part No. SWITCHING DIODE 1N4148 NDTZ001N4148 ZENER DIODE DZ-20BSBT265 NDTB00DZ20BS D322 SWITCHING DIODE 1SS133(T-77) or QDTZ001SS133 D612# ZENER DIODE MTZJT-7718B or QDTB00MTZJ18 SWITCHING DIODE 1N4148 NDTZ001N4148 ZENER DIODE DZ-18BSBT265 NDTB00DZ18BS D323 ZENER DIODE MTZJT-779.1B or QDTB0MTZJ9R1 D613 ZENER DIODE MTZJT-777.5B or...
  • Page 49 Ref. No. Description Part No. Ref. No. Description Part No. IC111 IC M61271M8-058FP-71 QSZAA0RMB182 TRANSISTOR KTC3198(GR) or NQS40KTC3198 IC151 IC:MEMORY S524C20D21 or NSZBA0SSM028 TRANSISTOR 2SC3331(T)-AANP or 2SC3331TZ IC:MEMORY AT24C02N-10SC or NSMMA0SAZ012 TRANSISTOR 2SC3331(U)-AANP or 2SC3331UZ IC(EEPROM) M24C02-MN6 or NSMMA0SSS028 TRANSISTOR 2SC1815-GR(TPE2) QQS102SC1815 IC:MEMORY BR24C02F-W or QSMBA0SRM003...
  • Page 50 Ref. No. Description Part No. Ref. No. Description Part No. CARBON RES. 1/4W J 220k Ω TRANSISTOR 2SC3331(T)-AANP or 2SC3331TZ RCX4JATZ0224 CARBON RES. 1/4W J 22k Ω TRANSISTOR 2SC3331(U)-AANP or 2SC3331UZ RCX4JATZ0223 CARBON RES. 1/4W J 100 Ω TRANSISTOR 2SC1815-GR(TPE2) QQS102SC1815 R101 RCX4JATZ0101...
  • Page 51 Ref. No. Description Part No. Ref. No. Description Part No. CHIP RES.(1608) 1/10W J 1k Ω CARBON RES. 1/4W J 15 Ω R346 RRXAJB5Z0102 R579# RCX4JATZ0150 CARBON RES. 1/4W J 27k Ω R348 RCX4JATZ0273 R581 PCB JUMPER D0.6-P5.0 JW5.0T CHIP RES.(1608) 1/10W J 3.3k Ω METAL OXIDE FILM RES.
  • Page 52 Ref. No. Description Part No. Ref. No. Description Part No. CARBON RES. 1/4W J 3.3k Ω CHIP RES. 1/10W J 0 Ω R672 RCX4JATZ0332 R862 RRXAJB5Z0000 CARBON RES. 1/4W J 100k Ω CHIP RES.(1608) 1/10W J 10k Ω R673 RCX4JATZ0104 R863 RRXAJB5Z0103 CHIP RES.(1608) 1/10W J 22k Ω...
  • Page 53 Ref. No. Description Part No. Ref. No. Description Part No. CHIP RES. 1/10W J 0 Ω J120 RRXAJB5Z0000 ELECTROLYTIC CAP . 10µF/50V M CE1JMASDL100 CHIP RES. 1/10W J 0 Ω J135 RRXAJB5Z0000 C1510 CERAMIC CAP . B K 1000pF/2KV or CCD3DKD0B102 CHIP RES.
  • Page 54 SST4274S L2712UN 2004-04-08...

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