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Toshiba 27a50 Service Manual
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Toshiba 27a50 Service Manual

Toshiba 27a50 Service Manual

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FILE NO. 020-200004

SERVICE MANUAL

COLOR TELEVISION
N0ES Chassis
27A50
(TAC0012)
PRINTED IN U.S.A. Apr., 2000 U

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Summary of Contents for Toshiba 27a50

  • Page 1: Service Manual

    FILE NO. 020-200004 SERVICE MANUAL COLOR TELEVISION N0ES Chassis 27A50 (TAC0012) PRINTED IN U.S.A. Apr., 2000 U...

  • Page 2: 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 ..............................16 CHAPTER 2 SPECIFIC INFORMATIONS SETTING & ADJUSTING DATA ..........................17 LOCATION OF CONTROLS ...........................

  • Page 3: 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 4: 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 (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 5 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 6 WARNING: BEFORE SERVICING THIS CHASSIS, READ THE “X-RAY RADIATION PRECAUTION”, “SAFETY PRECAU- TION” AND “PRODUCT SAFETY NOTICE” ON PAGE 3 OF THIS MANUAL. (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 7 CONVERGENCE ADJUSTMENTS 4-POLE NOTE: Before attempting any convergence adjustments, MAGNETS the receiver should be operated for at least fifteen 6-POLE minutes. 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 8: 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 9 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 17.) 5.
  • Page 10 8. SELF DIAGNOSTIC FUNCTION 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 11: 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 12: 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 ap- pears on the screen. 3. Adjust the FOCUS control (on T461) for well defined scanning lines on the picture screen.
  • Page 13 ITEM ADJUSTMENT PROCEDURE E-W PARABOLA 1. Call up the adjustment mode display, then select the item DPC. (DPC) 2. Press the TV/VIDEO button on Remote until the cross-hatch pattern appears on the screen. 3. Press the VOLUME s or t button to make vertical lines straight as shown below. HORIZONTAL POSITION 1.
  • Page 14 MTS ADJUSTMENT (FOR N5ES/N7S CHASSIS) ITEM INPUT SIGNAL ADJUSTMENT PROCEDURE • 1kHz 30% mod. → ANT ATTENUATOR 1. Connect rms meter to pin 12 of H002. (ATT) 2. Display item ATT on screen. terminal 3. Change data by VOLUME s/t buttons so that output at pin 12 of H002 becomes value as close as 142mVrms.
  • Page 15 MTS ADJUSTMENT (FOR N0ES CHASSIS) ITEM INPUT SIGNAL ADJUSTMENT PROCEDURE • 1kHz 30% mod. → ANT ATTENUATOR 1. Connect rms meter to pin 34 of QG01. (ATT) terminal 2. Display item ATT on screen. 3. Change data by VOLUME s/t buttons so that the reading of meter becomes value as close as 137mVrms.

  • 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 be- low. 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 27" HIGH VOLTAGE AT ZERO BEAM: 28.3kV MAX HIGH VOLTAGE: 29.7 kV Table-1 SERVICE MODE ADJUSTING ITEMS AND DATA IN THE SERVICE MODE: Item Name of adjustment Preset Data Item Name of adjustment Preset Data...

  • Page 18: Location Of Controls

    LOCATION OF CONTROLS Front view TV/VIDEO button VOLUME T/S button CHANNEL s/t button MENU TV / VIDEO VOLUME CHANNEL POWER T/S/t/s button POWER button MENU button Remote sensor POWER indicator Rear view COLOR VIDEO VIDEO VIDEO STREAM INPUT MONO MONO S-VIDEO AUDIO AUDIO...
  • Page 19 Remote MUTE button POWER RECALL MUTE RECALL button POWER buttons Channel Number buttons CH RTN CH RTN button MENU button CHANNEL s/t buttons MENU/ ENTER menu s/t buttons VOLUME T/S buttons menu T/S buttons TV/CABLE/VCR switch CABLE EXIT button Set to “TV” to control the TV. EXIT FAV CH TV/VIDEO...

  • Page 20: Programming Channel Memory

    PROGRAMMING CHANNEL MEMORY The channel memory is a 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 21: Circuit Block Diagram

    – 21 –...

  • Page 22: Chassis And Cabinet Replacement Parts List

    • The part number must be used when ordering parts, in order to assist in processing, be sure to include the Model number and Description. • The PC board assembly with mark is no longer available after the end of the production. Model : 27A50 Capacitors ..... CD Ceramic Disk : Plastic Film : Electrolytic Resistors ....
  • Page 23 Location Location Part No. Description Part No. Description C679 24667470 EL, 47?F, ±20%, 25V CG02 24203220 EL, 22?F, ±20%, 16V C681 24667102 EL, 1000?F, ±20%, 25V CG03 24539104 PF, 0.1?F C682 24668101 EL, 100?F, ±20%, 35V CG05 24797010 EL, 1?F, ±20%, 50V C683 24667102 EL, 1000?F, ±20%, 25V...
  • Page 24 Location Location Part No. Description Part No. Description CV41 24591223 PF, 0.022?F CZ10 24781100 Chip, 10pF, ±0.5pF%, SL CV60 24763471 EL, 470?F, ±20%, 16V CZ11 24781220 Chip, 22pF, SL CV61 24762471 EL, 470?F, ±20%, 10V CZ12 24814103 Chip, 0.01?F, +80%, -20% CY01 24474151 CD, 150pF, ±10%...
  • Page 25 Location Location Part No. Description Part No. Description R315 24366824 CF, 820k ohm R810 24569828 Cement, 0.82 ohm, R317 24366102 CF, 1k ohm ±10%, 10W R327 24339479 MF, 4.7 ohm, 2W R814 24366103 CF, 10k ohm R328 24366564 CF, 560k ohm R815 24552332 OMF, 3300 ohm, 1/2W...
  • Page 26 Location Location Part No. Description Part No. Description RA08 24366102 CF, 1k ohm RG23 24366101 CF, 100 ohm RA09 24366102 CF, 1k ohm RG36 24366472 CF, 4700 ohm RA10 24366102 CF, 1k ohm RG37 24366472 CF, 4700 ohm RA13 24366103 CF, 10k ohm RG41 24366103...
  • Page 27 Location Location Part No. Description Part No. Description RY14 24366102 CF, 1k ohm RZ17 24872471 Chip, 470 ohm, 1/16W RY15 24366273 CF, 27k ohm RZ18 24872122 Chip, 1200 ohm, 1/16W RY16 24872102 Chip, 1k ohm, 1/16W RZ19 24872332 Chip, 3300 ohm, 1/16W RY17 24872102 Chip, 1k ohm, 1/16W...
  • Page 28 Location Location Part No. Description Part No. Description Q203 23114528 Transistor, 2SC1740S, Q QS62 A6012040 Transistor, RN2204 Q204 A6002040 Transistor, RN1204 QS63 A6342200 Transistor, 2CS2878-A Q205 A6002040 Transistor, RN1204 QS64 A6342200 Transistor, 2CS2878-A Q301 B0378560 IC, TA8427K QV01 23906364 IC, MM1313BD Q301B 72471082 Screw, BRDT2W3X10 SZN...
  • Page 29 Screw, BTB 3X12 SZN AT03 23588307 Battery Cover F301 23144908 Fuse, 0.5A, 125V Y101 23563890 Owner’s Manual, English, F301A 23165433 Holder, Fuse 27A50 F470 23144785 Fuse, 1.25A, 125V Y101F 23563891 Owner’s Manual, French, F470A 23165433 Holder, Fuse 27A50 F801 23144888 Fuse, 5.0A, 125V...
  • Page 30 THIS PAGE IS INTENTIONALLY LEFT BLANK. – 30 –...

  • Page 31: Pc Boards Bottom View

    MAIN BOARD PB9549A BOTTOM (FOIL) SIDE – 31 – – 32 –...

  • Page 32: Terminal View Of Transistors

    CRT DRIVE BOARD PB8625B 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 33 MEMO ..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................– 35 –...
  • Page 34 MEMO ..........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................– 36 –...

  • Page 35: 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 36: Schematic Diagram

    SCHEMATIC DIAGRAM MODEL : 27A50 Chassis No. TAC0012 WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "X-RAY RADIATION PRECAUTION", "SAFETY PRECAUTION" AND "PRODUCT SAFETY NOTICE" ON THE MANUAL FOR THIS MODEL. CAUTION: The international hazard symbols "*" in the schematic diagram and the parts list designate components 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 37 SCHEMATIC DIAGRAM MODEL : 27A50 Chassis No. TAC0012 NOTE: WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "X-RAY RADIATION PRECAUTION", "SAFETY PRECAUTION" AND "PRODUCT SAFETY NOTICE" ON THE MANUAL FOR THIS MODEL. 1. RESISTOR Resistance is shown in ohm [K = 1.000, M = 1.000.000]. All resistors are 1/6W and 5% 4.
  • Page 55 TOSHIBA CORPORATION 1-1, SHIBAURA 1- CHOME, MINATO-KU, TOKYO 105-8001, JAPAN...

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