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Panasonic CT-20DC50B Service Manual
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Panasonic CT-20DC50B Service Manual

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Service Manual

This Service manual is issued as a service guide for the models of the NA6DVD family listed above. Included in this
manual are a set of schematic, block diagrams, functional descriptions, alignment procedures, disassembly
procedures, and a complete parts list.
"WARNING! This Service Manual is designed for experienced repair technicians only and is not designed for use by the general public.
It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product.
Products powered by electricity should be serviced or repaired only by experienced professional technicians. Any attempt to
service or repair the product or products dealt with in this Service Manual by anyone else could result in serious injury or death."
The service technician is required to read and follow the "Safety Precautions" and "Important Safety Notice" in this Main Manual.
珍惜眼前人 搜集整理
Color Television
Main Manual
Model
CT-20DC50B
Copyright 2001 by Matsushita Electric Corporation of
America. All rights reserved. Unauthorized copying
and distribution is a violation of law.
QQ:362399998
ORDER NO. MTNC000939C1
B1
(NA6DVD)
Panasonic
Chassis
AP348
QQ群:12919880

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Summary of Contents for Panasonic CT-20DC50B

  • Page 1: Service Manual

    (NA6DVD) Panasonic Model Chassis CT-20DC50B AP348 This Service manual is issued as a service guide for the models of the NA6DVD family listed above. Included in this manual are a set of schematic, block diagrams, functional descriptions, alignment procedures, disassembly procedures, and a complete parts list.

  • Page 2: Important Safety Notice

    Important Safety Notice Special components are used in this Receiver that are important for safety. These parts are identified on the schematic diagram by the symbol and printed in BOLD TYPE on the replacement part list. It is essential that these critical parts be replaced with the manufacturer’s specified replacement part to prevent X-ray radiation, shock, fire or other hazards.

  • Page 3: Table Of Contents

    Important Safety Notice ....2 Service Adjustments (Electronic Control)....28 Safety Precautions .

  • Page 4: Service Notes

    Service Notes Note: These components are affixed with glue. Be careful not to break or damage any foil under the component or at the pins of the ICs when removing. Usually applying heat to the component for a short time while twisting with tweezers will break the component loose. Leadless Chip Component How to Replace Flat-IC (Surface mount)

  • Page 5: Horizontal Oscillator Disable Circuit

    Horizontal Oscillator Disable Circuit IMPORTANT: To protect against possible damage to the solid state devices due to arcing or static This chassis employs a special circuit to protect discharge, make certain that all ground wires and CRT against excessive high voltage and beam current. If, for DAG wire are securely connected.

  • Page 6: Receivers Feature Table

    Receiver Feature Table FEATURE FEATURE Surround Chassis AP348M Built-in audio power 5W x 2 (10%) Tunning system # of speakers # of channels A/V in (rear/front) 2(2/1) Menu language Eng/Span/Fr S-VHS Input (rear/ Closed Caption front) V-Chip Audio Out input (FAO &...

  • Page 7: Location Of Controls

    Location of Controls Input Jacks Remote Control Sensor 7 8 9 10 11 Figure 2. Location of Controls Quick Reference Control Operation Power - Press to turn “ON” or “OFF”. Volume - Press to adjust Sound Level, or to adjust Audio Menus, Video Menus, and select operating features when menus are displayed Channel - Press to select programmed channels.

  • Page 8: Remote Control (Eur511503)

    EMOTE ONTROL POWER Press to turn ON and OFF. LIGHT Press to light remote control buttons. TV DVD CBL/DBS VCR Press to select remote operation. ACTION Press to access menu or enter selections Press to adjust TV sound and navigate in menus. Press to select next channel and navigate in menus.

  • Page 9: Receiver Exploded View

    Receiver Exploded View Figure 4. Receiver Exploded View LOCATION OF COMPONENTS Cabinet Front A-Board Tray Panel Back Cover Chassis Rails (L & R) Panasonic Badge A-V Rear Bracket M-Board Mount Metal Front Speaker P-Board Mount Metal Rear Buttons K-Board DVD Bracket...

  • Page 10: Disassembly For Service

    Disassembly for Service Back Cover C-Board - CRT Output Socket plugs onto the CRT neck. Remove all the screws marked with an arrow( from the back of the Receiver. • 3 screws at the top edge of the Receiver. • 1 screw at each lower corner of the Receiver.

  • Page 11: K-Board - Customer Controls

    K-Board - Customer Controls (Keyboard W-Board - Connector Interface Board Push Button Assembly) Located underneath the DVD unit. Secured to the DVD enclosure with 2 screws. Fastened to the inside of the cabinet front with 3 screws. The push button unit is attached to the Speakers K-Board with 4 snap tabs (spring action).

  • Page 12: Dvd Replacement

    Detailed side view 30~40mm DEG Coil IMPORTANT NOTE: Mounting Ear Reuse hardware (screws, Clamper bolts, connectors, etc.) upon reassembling the Receiver. CRT Face Clamper (4 places) DAG GND DEG Coil DEG Coil Connector DAG GND Connector Figure 12. Fixing of DEG (degaussing) coil and DAG GND. DVD Replacement P-Board Note: Observe universal STATIC PRECAUTIONS...
  • Page 13 Shipping Grounding “Plug” Flat cable W-Board Figure 15. DVD Unit Shipping Grounding “Plug” Removal Figure 14. DVD Unit Connection - 13 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 14: Component Identification

    Component Identification Rear Front Figure 16. Receiver Internal View LOCATION OF COMPONENTS INTEGRATED CIRCUITS BOARDS TRANSISTORS VARIOUS IC 001 MPU A Board Q501 HOR. T551 (Flyback) IC 002 EEPROM C Board Q551 HOR. A/V Jacks IC 101 VCJ JJ Board Fuse (F801) IC 6501 3L Filter M Board...
  • Page 15 Figure 17. Side View - P-Board Figure 18. Side View - M-Board, Tuner & JJ-Board Figure 19. Side View - P-Board & Mounting Rail - 15 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 16: G-Board Installation

    Figure 20. Side View - M-Board & Mounting Rail G-Board Installation Verify that when the cables leading from the A-Board to the G-Board are replaced, the ferrite beads are installed. See Fig. 21. G-Board Ferrite Bead Figure 21. G-Board Cables & Ferrite Beads Assembly IMPORTANT NOTE: Reuse hardware...

  • Page 17: Chassis Service Adjustment Procedures

    Chassis Service Adjustment Procedures All service adjustments are factory preset and should not require adjustment unless controls and/or associated components are replaced. Note: Connect the (-) lead of the voltmeter to the appropriate ground. Use IC803’s heat sink when the HOT ground symbol ( ) is used.

  • Page 18: Purity And Convergence Procedures

    Purity and Convergence Procedure Adjustment is necessary only if the CRT or the For a 1-piece assembly (see Fig. 26): deflection yoke is replaced or if the setting was Position like tabs of purity devices together at 12 disturbed. The complete procedure consists of: o’clock to reduce any magnetic field effect.
  • Page 19 Initial Center Static Convergence For a 1-piece assembly (see Fig. 26): Slowly move the deflection yoke and purity rings Connect a dot/cross hatch generator to the Receiver assembly toward the CRT board and adjust the purity and tune in a signal. Observe misconvergence at magnet rings to set vertical green raster at center of center of the screen only.
  • Page 20 Figure 29. Vertical Yoke Movement Figure 30. Horizontal Yoke Movement Figure 31. Convergence Magnets and Wedges Location Note: For models using 4 pairs of rings assemblies see Fig. 24 for details - 20 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 21: Service Mode (Electronic Controls)

    Service Mode (Electronic Controls) This Receiver has electronic technology using the I²C 6. “CHK” = Normal operation of CHANNEL Bus Concept. It performs as a control function and it and VOLUME replaces many mechanical controls. Instead of adjusting mechanical controls individually, many of the control functions are now performed by using “On Screen Display Menu”.

  • Page 22: Sub-Data Adjustment

    Press Power on the Remote Control to select the Service Adjustment. For Adjustments: 1.Press Channel Up/Down on the Note: Write Down the original 2.Press Volume Up/Down on the Remote Control to select one of value set (b in Fig. 32) for Remote Control to adjust the the available Service Adjustments each...

  • Page 23: Options Adjustment

    Press Power on the Remote Control to select the Service Adjustment For Adjustments: 1.Press Channel Up/Down on the Note: Write Down the original 2.Press Volume Up/Down on the Remote Control to select one of value set (b in Fig. 32) for Remote Control to adjust the the available Service Adjustments each...

  • Page 24: Comb Filter Adjustment

    Press Power on the Remote Control to select the Service Adjustment For Adjustments: 1.Press Channel Up/Down on the Note: Write Down the original 2.Press Volume Up/Down on the Remote Control to select one of value set (b in Fig. 32) for Remote Control to adjust the each address...

  • Page 25: To Check Purity

    To Check Purity: Press Recall on the Remote Control when in Service Mode (red “CHK” is displayed) to enter the Purity Field Check Mode. NORMAL SCREEN Press Recall again to select desired field. BLUE GRN. WHITE SCREEN SCREEN SCREEN SCREEN Figure 33.

  • Page 26: Instructional Flow Chart For Service Mode

    Instructional Flow Chart for Service Mode NOTE Always Exit the Service Mode Following Adjustments. NORMAL MODE Momentarily short FA1 to FA2 ( AGING MODE • Yellow “CHK” appears in upper left corner of screen. WHITE • Volume Up/Down operate rapidly. SCREEN •...
  • Page 27 Instructional Flow Chart for Service Mode - Continued LOUDNESS COMPENSATION (ON REMOTE) VCJ TEST PIP TINT CUT-OFF ADJUSTMENTS. BEAM LIMIT CLOCK C ITEMS. ADJUSTMENT HORIZ CENTER FREERUN YNR VID ADJ Adj. RIGH 1/16 RF-AGC needed? LEFT 1/16 DOWN 1/16 YNR SWITCH UP 1/16 (ON REMOTE) DRIVE B...

  • Page 28: Service Adjustments

    Service Adjustments (Electronic Controls) Sub-Brightness Preparation: 1. Apply a color bar signal pattern with 87.5% Service DAC Adjustment (B2) modulation, 70% saturated color bar with 100 IRE Adjustment of this control is important for setting proper white and 7.5 black. operation of customer brightness and picture controls.

  • Page 29: Tint/Color Adjustment

    4. Remove the jumpers (Preparation steps 4 & 5). Color Temperature Adjustment (B/W Tracking) 2.8V ± 0.1V Service DAC Adjust. (C0) (C1) (C2) (C3) (C4) Minor Touch-Up Method OBSERVE low and high brightness areas of a B/W 1.0V - 1.5V picture for proper tracking.

  • Page 30: Horizontal Centering

    period of 175V above DC ground is measured, as performed only when IC002 or IC101 is replaced. indicated in Fig. 42. Preparation: 1. Apply the following signal at the antenna (70dB ± 5dB, 75 open P/S 10dB): audio signal set to monaural, 300Hz.

  • Page 31: Clock Adjustment (Sb)

    Video: 100 IRE flat field, 30% modulation. 2. Measure TPS1 (IC001 pin 13) for the frequency of Audio: 300Hz, 100% modulation, stereo (left only) the waveform and record the reading. (70 ± 5dB, 75 OPEN, P/S 10dB). 3. Adjust the MTS Low-Level Separation Adjustment Note: Pin 13 measurement must have at least four (M2) until the amplitude displayed on the scope is digits of resolution following the decimal point.

  • Page 32: Audio Signal Path Block Diagram

    Audio Signal Path Block Diagram Figure 45. Audio Signal Path Block Diagram - 32 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 33: Video-Chroma Signal Path Block Diagrams

    Video-Chroma Signal Path Block Diagram Figure 46. Video-Chroma Path Block Diagram - 33 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 34: Ic101 Vcj In/Out Pins And Functions

    IC101 IN/OUT Pins and Functions (VCJ) Figure 47. IC101 IN/OUT Pins and Functions (VCJ). - 34 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 35: Ic001 Mpu In/Out Pins And Functions

    IC001 IN/OUT Pins and Functions (MPU) Figure 48. IC001 IN/OUT Pins and Functions (MPU) - 35 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...
  • Page 36 NOTES - 36 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 37: Parts List

    REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION C304 ECEA1HNR47UB CAP,E .47UF-50V...

  • Page 38: Replacement Parts List

    REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...
  • Page 39 REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...
  • Page 40 REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...
  • Page 41 REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...
  • Page 42 REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...
  • Page 43 REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...
  • Page 44 REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...
  • Page 45 REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...

  • Page 46: Description Of Abbreviation Guide

    REPLACEMENT PARTS LIST Model: CT-20DC50B Important Safety Notice: Components printed in BOLD TYPE have special characteristics important for safety. When replacing any of these components use only manufacturer’s specified parts. REF NO. PART NO. DESCRIPTION REF NO. PART NO. DESCRIPTION...

  • Page 47: Schematic Notes

    Schematic Notes IMPORTANT SAFETY NOTICE CHIP TRANSISTOR THIS SCHEMATIC DIAGRAM INCORPORATES SPECIAL LEAD DESIGNATION FEATURES THAT ARE IMPORTANT FOR PROTECTION FROM X-RADIATION, FIRE AND ELECTRICAL SHOCK HAZARDS. WHEN SERVICING ESSENTIAL THAT ONLY MANUFACTURERS SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS DESIGNATED WITH A IN THE SCHEMATIC.
  • Page 48 Schematic Notes NOTA DE SEGURIDAD DIAGRAMAS ELÉCTRICOS INCLUYEN CARACTERÍSTICAS ESPECIALES MUY IMPORTANTES IDENTIFICACIÓN DE TERMINALES PARA TRANSISTORES EN CHIP PARA PROTECCIÓN CONTRA RAYOS-X, QUEMADURAS Y DESCARGAS ELÉCTRICAS. CUANDO SERVICIO IMPORTANTE USAR PARA REEMPLAZO COMPONENTES CRITICOS, SOLO PARTES ESPECIFICADAS POR EL FABRICANTES. LOS COMPONENTES CRITICOS ESTAN SEÑALADOS EN LOS DIAGRAMAS POR EL SIMBOLO NOTAS DE LOS DIAGRAMAS...
  • Page 49 Schematic Notes 1. RESISTOR Unit of resistance is ohm ( K=1,000, M=1,000,000) :  Non Flammable Solid Metal Oxide Metal (Precision and high stability) Wire Wound Thermistor Fusible Positive coefficient Thermistor Flame Proof Rectangular 2. CAPACITOR Unit of capacitance is F, unless otherwise noted. Electrolytic Metallized Polyester Tantalum...
  • Page 50 Schematic Notes - 50 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 51: Schematics And Voltages G - Board

    G & K-BOARD SCHEMATICS & LAYOUTS -- DIAGRAMAS ELÉCTRICOS Y CIRCUITOS IMPRESOS DE LAS TARJETAS G Y K G & K-BOARDS -- TARJETAS G Y K Note • The board layouts were modified to enhance and display traces otherwise hidden by a mask. Nota •...

  • Page 52: A - Board

    A-BOARD -- TARJETA A A-BOARD SCHEMATIC LEFT PORTION -- DIAGRAMA ELÉCTRICO TARJETA A SECCIÓN IZQUIERDA - 52 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...
  • Page 53 A-BOARD -- TARJETA A A-BOARD SCHEMATIC RIGHT PORTION -- DIAGRAMA ELÉCTRICO TARJETA A SECCIÓN DERECHA CHIP TRANSISTOR LEAD DESIGNATION IDENTIFICACIÓN DE TERMINALES PARA TRANSISTORES EN CHIP - 53 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 54: Jj - Board

    JJ-BOARD - TARJETA JJ JJ-BOARD SCHEMATIC LEFT PORTION -- DIAGRAMA ELÉCTRICO TARJETA JJ SECCIÓN IZQUIERDA - 54 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...
  • Page 55 JJ-BOARD -- TARJETA JJ JJ-BOARD SCHEMATIC RIGHT PORTION -- DIAGRAMA ELÉCTRICO TARJETA JJ SECCIÓN DERECHA IDENTIFICACIÓN DE TERMINALES CHIP TRANSISTOR PARA TRANSISTORES EN CHIP LEAD DESIGNATION - 55 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 56: M - Board

    M-BOARD -- TARJETA M M-BOARD SCHEMATIC, LAYOUT & VOLTAGES -- DIAGRAMA ELÉCTRICO, CIRCUITO IMPRESO Y VOLTAJES TARJETA M IC3502 IC3501 Note ..4.96 ..4.96 ..2.47 ..3.27 •...

  • Page 57: Voltages (A-Board)

    A-BOARD VOLTAGES -- VOLTAJES TARJETA A A-BOARD -- TARJETA A IC001 IC101 IC2321 ..4.41 ..0.00 ..2.86 ..n.c ..4.38 .

  • Page 58: P- Board

    P-BOARD -- TARJETA P P-BOARD SCHEMATIC -- DIAGRAMA ELÉCTRICO TARJETA P - 58 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 59: Voltages (P-Board)

    P-BOARD LAYOUT & VOLTAGES -- CIRCUITO IMPRESO Y VOLTAJES TARJETA P P-BOARD - TARJETA P IC866 IC881 IC891 IC896 ..5.16 ..GND ..4.01 ..GND .

  • Page 60: W - Board

    W-BOARD SCHEMATIC & LAYOUT -- DIAGRAMA ELÉCTRICO Y CIRCUITO IMPRESO TARJETA W W-BOARD -- TARJETA W Note • The board layouts were modified to enhance and display traces otherwise hidden by a mask. Nota • Los circuitos impresos las tarjetas han sido modificados par mayor claridad.

  • Page 61: Voltages (Jj-Board)

    JJ-BOARD LAYOUT & VOLTAGES -- CIRCUITO IMPRESO Y VOLTAJES TARJETA JJ JJ-BOARD -- TARJETA JJ CHIP TRANSISTOR LEAD DESIGNATION IDENTIFICACIÓN DE TERMINALES PARA TRANSISTORES EN CHIP IC3603 IC3001 IC3002 IC3601 IC3602 ..n.c ..GND .

  • Page 62: A - Board

    A-BOARD -- TARJETA A A-BOARD LAYOUT -- CIRCUITO IMPRESO TARJETA A - 62 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...

  • Page 63: C - Board

    C-BOARD LAYOUT & VOLTAGES -- CIRCUITO IMPRESO & VOLTAJES TARJETA C C-BOARD -- TARJETA C Notes: • Check Parts List for most recent component values and part numbers. • Obtain voltages with a digital multimeter. • The board layouts were modified to enhance and display traces otherwise hidden by a mask.

  • Page 64: Waveforms

    A-BOARD -- TARJETA A A-BOARD WAVEFORMS -- FORMAS DE ONDA TARJETA A Waveforms - A-Board 3.58MHz X’tal IC101 PIN 1 1.7V p-p [20µs] 30.8V p-p [5ms] 7.4V p-p [20µs] 324.0V p-p [5µs] 2.0V p-p [20µs] 3.58VCO IC101 PIN 41 (SYNC) IC451 PIN 13 IC803 PIN 2 IC101 PIN 33 (DET OUT)
  • Page 65 Notes - 65 - 珍惜眼前人 搜集整理 QQ:362399998 QQ群:12919880...
  • Page 66 SERVICEMAN MODE (ELECTRONIC CONTROL) SERVICE ADJUSTMENT VALUES Model _____________________________________________ Ser #_____________ Date_________________ Note: Record the original settings PRIOR to modifying the registers. Service Adjustment Def. Original Service Adjustment Def. Original Mode Mode Adjustment Range Val. Value Value Adjustment Range Val. Value Value Sub Adjustments...

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