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Toshiba 14AS20 Service Manual

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SERVICE MANUAL
COLOR TELEVISION
14AS20 is the same as 19A20 except for the parts and setting & adjusting data tabled
on back of this sheet.
Use this service manual together with the service manual of 19A20 (File No. 020-200003).
14AS20
– SUMMARY –
FILE NO. 063-200006
N0E Chassis
(TAC0002)
PUBLISHED IN JAPAN, Aug., 2000 So

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Summary of Contents for Toshiba 14AS20

  • Page 1 14AS20 (TAC0002) – SUMMARY – 14AS20 is the same as 19A20 except for the parts and setting & adjusting data tabled on back of this sheet. Use this service manual together with the service manual of 19A20 (File No. 020-200003).
  • Page 2 23102409 Magnet, Purity-Convergence, R306 24366683 CF, 68k ohm MAG-1070 R307 24366474 CF, 470k ohm Y101 23565007 Owner’s Manual, R312 24381222 OMF, 2200 ohm, 1/2W English/Spanish, 14AS20 R313 24366274 CF, 270k ohm TOSHIBA CORPORATION 1-1, SHIBAURA 1-CHOME, MINATO-KU, TOKYO 105-8001, JAPAN...
  • Page 3 FILE NO. 020-200003 SERVICE MANUAL COLOR TELEVISION N0E Chassis 19A20 (TAC0001) PRINTED IN U.S.A. Mar., 2000 U...

  • Page 4: Table Of Contents

    TABLE OF CONTENTS CHAPTER 1 GENERAL ADJUSTMENTS SAFETY INSTRUCTIONS ............................3 SET-UP ADJUSTMENT ............................4 SERVICE MODE ..............................8 DESIGN MODE ..............................11 ELECTRICAL ADJUSTMENTS ..........................12 CIRCUIT CHECKS ..............................14 CHAPTER 2 SPECIFIC INFORMATIONS SETTING & ADJUSTING DATA ..........................15 LOCATION OF CONTROLS ...........................

  • Page 5: Chapter 1 General Adjustments

    CHAPTER 1 GENERAL ADJUSTMENTS SAFETY INSTRUCTIONS WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAU- TION” AND “PRODUCT SAFETY NOTICE” INSTRUCTIONS BELOW. X-RAY RADIATION PRECAUTION 1. Excessive high voltage can produce potentially hazard- 2. This receiver is equipped with a Fail Safe (FS) circuit which ous X-RAY RADIATION.

  • Page 6: Set-Up Adjustment

    WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAU- TION” AND “PRODUCT SAFETY NOTICE” ON PAGE 3 OF THIS MANUAL. SET-UP ADJUSTMENT SET-UP ADJUSTMENT FOR 13", 14", 19", 20". The following adjustments should be made when a complete realignment is required or a new picture tube is installed. Perform the adjustments in order as follows : 1.
  • Page 7 CONVERGENCE ADJUSTMENTS CIRCUMFERENCE CONVERGENCE ADJUSTMENT NOTE: Before attempting any convergence adjustments, the 1. Loosen the clamping screw of deflection yoke slightly to receiver should be operated for at least fifteen min- allow the yoke to tilt. utes. 2. Temporarily put a wedge as shown in figure 1. (Do not remove cover paper on adhesive part of the wedge.) CENTER CONVERGENCE ADJUSTMENT 3.
  • Page 8 WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAU- TION” AND “PRODUCT SAFETY NOTICE” ON PAGE 3 OF THIS MANUAL. SET-UP ADJUSTMENT FOR 35", 36". The following adjustments should be made when a complete realignment is required or a new picture tube is installed. Perform the adjustments in order as follows : 1.
  • Page 9 CONVERGENCE ADJUSTMENTS NOTE: Before attempting any convergence adjustments, 4-POLE the receiver should be operated for at least fifteen MAGNETS minutes. 6-POLE MAGNETS CENTER CONVERGENCE ADJUSTMENT 1. Display built-in cross-dot pattern using the TEST SIG- NAL SELECTION function. 2. Adjust the BRIGHTNESS and CONTRAST Controls for well defined pattern.

  • Page 10: Service Mode

    SERVICE MODE 1. ENTERING TO SERVICE MODE 1) Press MUTE button once 2) Press MUTE button 3) While pressing the MUTE button, on Remote Control. again to keep pressing. press MENU button on TV set. MUTE (Service mode display) 2. DISPLAYING THE ADJUSTMENT MENU 1) Press MENU button on TV.
  • Page 11 4. SELECTING THE ADJUSTING ITEMS 1) Every pressing of CHANNEL s button in the service mode changes the adjustment items in the order of table-2. (t button for reverse order) Refer to table-2 for preset data of adjustment mode. (See SETTING & ADJUSTING DATA on page 15) 5.
  • Page 12 8. SELF DIAGNOSTIC FUNCTION (MTS Model) 1) Press “9” button on Remote Control during display of adjustment menu in the service mode. The diagnosis will begin to check if interface among IC’s are executed properly. 2) During diagnosis, the following displays are shown. SELF CHECK NO.

  • Page 13: Design Mode

    DESIGN MODE 1. ENTERING TO DESIGN MODE 1) Select the Service mode. 2) While pressing RECALL button on. 3) Press MENU button on TV. Remote and press MENU button on TV. ITEM Press DATA Press (Design mode) (Adjustment mode) When QA02 is initialized, items “OPT0” and “OPT1” of DESIGN MODE are set to the data of the representative model of this chassis family.

  • Page 14: Electrical Adjustments

    ELECTRICAL ADJUSTMENTS ITEM ADJUSTMENT PROCEDURE FOCUS VR ADJ. 1. Enter the service mode, then select any register item. 2. Press the TV/VIDEO button on the Remote until the black cross-bar pattern appears on the screen. 3. Adjust the FOCUS control (on T461) for well defined scanning lines on the picture screen.
  • Page 15 ITEM ADJUSTMENT PROCEDURE WHITE BALANCE 1. Adjust the CONTRAST control to the center, and BRIGHTNESS control to the RCUT maximum. GCUT 2. Call up the adjustment mode display, and press the TV/VIDEO button until the BCUT white and black pattern appears on the screen. GDRV 3.

  • Page 16: Circuit Checks

    CIRCUIT CHECKS HIGH VOLTAGE CHECK Troubleshooting Guide for Fail Safe Circuit CAUTION: There is no HIGH VOLTAGE ADJUSTMENT on this chassis. Checking should be done following the steps below. Check that the set returns to normal operation when pin 12 1.

  • Page 17: Chapter 2 Specific Informations

    CHAPTER 2 SPECIFIC INFORMATIONS SETTING & ADJUSTING DATA SAFETY INSTRUCTIONS 19" HIGH VOLTAGE AT ZERO BEAM: 24.7 kV MAX HIGH VOLTAGE: 26.1 kV Table-1 SERVICE MODE ADJUSTING ITEMS AND DATAS IN THE SERVICE MODE: Item Name of adjustment Reference Data RCUT RED CUT-OFF GCUT...

  • Page 18: Location Of Controls

    LOCATION OF CONTROLS Front POWER MENU VOLUME CHANNEL Remote sensor Remote Control POWER TV/VIDEO POWER button TV/VIDEO button Channel Number button CH RTN RTN button RECALL button RECALL MUTE MUTE button VOLUME T / S button CHANNEL s/t buttons (Menu T / S button) (Menu s/t buttons) MENU button EXIT button...

  • Page 19: Programming Channel Memory

    PROGRAMMING CHANNEL MEMORY The channel memory is the list of TV channel numbers your TV will stop on when you press the CHANNEL s or t button. First, use the TV/CABLE and CH PROGRAM functions to preset all active channels in your area. If necessary, arrange the preset channels with the ADD/ERASE functions so that you can tune into only desired channels.

  • Page 20: Circuit Block Diagram

    – 18 –...

  • Page 21: Chassis And Cabinet Replacement Parts List

    CHASSIS AND CABINET REPLACEMENT PARTS LIST WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAUTION” AND “PRODUCT SAFETY NOTICE” ON PAGE 3 OF THIS MANUAL. CAUTION: The international hazard symbols “ ” in the schematic diagram and the parts list designate com- ponents which have special characteristics important for safety and should be replaced only with types identical to those in the original circuit or specified in the parts list.
  • Page 22 Location Location Part No. Description Part No. Description EL, 0.47?F, ±20%, 50V CS03 24797478 R602 24532100 FR, 10 ohm, 1W EL, 0.47?F, ±20%, 50V CS11 24797478 R603 24366391 CF, 390 ohm CT63 24591223 PF, 0.022?F R604 24366182 CF, 1800 ohm EL, 0.47?F, ±20%, 50V CV06 24797478...
  • Page 23 Location Location Part No. Description Part No. Description RA68 24366103 CF, 10k ohm QB03 A6002050 Transistor, RN1205 RA70 24366333 CF, 33k ohm QB21 23114528 Transistor, 2SC1740S, Q RA71 24366683 CF, 68k ohm QB30 23114528 Transistor, 2SC1740S, Q RA72 24366223 CF, 22k ohm QB33 70119743 IC, PST523D...
  • Page 24 Location Location Part No. Description Part No. Description XA01 23153504 Ceramic Resonator, 8.00MHz, TCR1056BM Z001 23134187 CR-GAP, CRA112G PC BOARD ASSEMBLIES PC BOARD ASSEMBLIES PC BOARD ASSEMBLIES PC BOARD ASSEMBLIES PC BOARD ASSEMBLIES M051Z Main Board, PB9391A-1 M052Z CRT Drive Board, PB9391A-2 PICTURE TUBE PICTURE TUBE PICTURE TUBE...

  • Page 25: Pc Boards Bottom View

    MAIN BOARD PB9391-1 BOTTOM (FOIL) SIDE – 23 – – 24 –...

  • Page 26: Terminal View Of Transistors

    CRT-D DRIVE BOARD PB9391-2 TERMINAL VIEW OF TRANSISTORS BOTTOM (FOIL) SIDE 2SD2253 2SC3852 2SC752GTM 2SC752 2SA1788 (old) 2SD1763A 2SC2482 2SA562TM 2SC5243 2SC1569 2SC2655 2SA1015 2SC4544 2SC4721P 2SC1815 2SA1788 2SC2878 2SA1306 2SC1740S 2SA1186A 2SC2120 2SA9335 ON4409 RN2203 2SD1554 RN2201 2SD2253 RN2004 2SD1556 RN1203 2SC5143...
  • Page 27 MEMO ..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................– 27 –...
  • Page 28 MEMO ..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................– 28 –...

  • Page 29: Specifications

    SPECIFICATIONS TELEVISION SYSTEM NTSC standard CHANNEL COVERAGE VHF; 2 through 13 UHF; 14 through 69 Cable TV; mid band (A-8 through A-1, A through I) super band (J through W) hyper band (AA through ZZ, AAA, BBB) ultra band (65 through 94, 100 through 125) POWER SOURCE 120V AC, 60Hz POWER CONSUMPTION...
  • Page 30 TOSHIBA CORPORATION 1-1, SHIBAURA 1- CHOME, MINATO-KU, TOKYO 105-8001, JAPAN...

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