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Mitsubishi Electric WT-42311 Service Manual

Projection television
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MITSUBISHI ELECTRIC
CAUTION:
Before servicing this chassis, it is important that the service person read the "SAFETY PRECAUTIONS" and
"PRODUCT SAFETY NOTICE" contained in this manual.
• Power
: AC 120V, 60Hz
240W
• Frequency
: VHF 54 ~ 470MHz
Range
UHF 470 ~ 806MHz
• Antenna Input
: VHF/UHF 75Ω unbalanced
• CRT Size
: [7 inches]
• High Voltage
: 32.0kV (at 0A)
• Cabinet
: 39"(W)x34"(H)x25"(D)
Dimensions
• Weight
: 105 lbs
• Weight and dimensions shown are approximate.
• Design specifications are subject to change without notice.
MITSUBISHI DIGITAL ELECTRONICS AMERICA, INC.
Copyright © 2002 Mitsubishi Digital Electronics America, Inc.
Service
Manual
PROJECTION TELEVISION
VK20 CHASSIS

SPECIFICATIONS

9351 Jeronimo Road, Irvine, CA 92618-1904
All Rights Reserved
WT-42311
WT-A42
• Speaker
: Two 5" round, full range (8Ω 5W)
• Input Level
: VIDEO IN JACK (RCA Type)
1.0Vp-p 75Ω unbalanced
: AUDIO IN JACK (RCA Type)
-4.7dBm 43kΩ unbalanced
: S-VIDEO IN JACK (Y/C separate)
Y=1.0 Vp-p C=0.286Vp-p(BURST)
75Ω unbalanced
: COMP / Y, Cr, Cb (RCA Type)
Y=1.0 Vp-p. Cr, Cb=700mVp-p
: ATV / Y(G), Pr(R), Pb(B), H, V
Y 1.0Vp-p with sync 75Ω (RCA Type)
Pr, Pb: 700mV 75Ω
H, V: 3.0Vp-p 75Ω
• Output Level
: VIDEO OUT JACK (RCA Type)
1.0Vp-p 75Ω unbalanced
: AUDIO OUT JACK (RCA
-4.7dBm 4.7k
2002
2002
2002
2002
2002
Type)
Ω
unbalanced

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Summary of Contents for Mitsubishi Electric WT-42311

  • Page 1: Schematic Diagrams Overall Block Diagram

    2002 2002 2002 2002 2002 Service MITSUBISHI ELECTRIC Manual PROJECTION TELEVISION VK20 CHASSIS WT-42311 WT-A42 CAUTION: Before servicing this chassis, it is important that the service person read the "SAFETY PRECAUTIONS" and "PRODUCT SAFETY NOTICE" contained in this manual. SPECIFICATIONS •...

  • Page 3: Table Of Contents

    MODELS: WT-42311 / WT-A42 CONTENTS INTRODUCTION ..........................5 PRODUCT SAFETY NOTICE ......................5 SAFETY PRECAUTIONS ........................6 CABINET DISASSEMBLY Front View Disassembly ......................... 7 Rear View Disassembly ........................8 SERVICING THE LENTICULAR SCREEN AND FRESNEL LENS Lenticular Screen and Fresnel Lens Removal .................. 9 Lenticular Screen and Fresnel Lens Installation ................

  • Page 4: Pcb-Terminal (Input Sw)

    MODELS: WT-42311 / WT-A42 REPLACEMENT PARTS Parts Ordering ..........................38 Critical and Warranty Parts Designation..................38 Parts Tolerance Codes ........................38 Replacement Part Notes When replacing the RF-Switch or PCB-SIGNAL ..............38 When replacing the EEPROM....................38 Quick Reference List ........................39 Service Parts List..........................

  • Page 5: Introduction

    MODEL: WT-42311 / WT-A42 INTRODUCTION This service manual provides service instructions for PTV Models WT-42311and WT-A42 using the VK20 chassis. Service personnel should read this manual thoroughly before servicing this chassis. This service manual includes: 1. Assembly and disassembly instructions for the front and rear cabinet components.

  • Page 6: Safety Precautions

    MODEL: WT-42311 / WT-A42 SAFETY PRECAUTIONS NOTICE: Observe all cautions and safety related notes located inside the receiver cabinet and on the receiver chassis. WARNING: Operation of this receiver outside the cabinet or with the cover removed presents a shock hazard from the receiver's power supplies.

  • Page 7: Cabinet Disassembly

    MODEL: WT-42311 / WT-A42 CABINET DISASSEMBLY (FRONT VIEW) *Refer to PARTS LIST for Part Numbers Front Cabinet Disassembly 1. Remove the Speaker Grille by pulling forward. 2. Remove the Board-Front by removing 3 screws "a". 3. Remove 3 screws “b” and then remove the Front Mask and Diamond Shield.

  • Page 8: Rear View Disassembly

    MODEL: WT-42311 / WT-A42 CABINET DISASSEMBLY (REAR VIEW) Rear Cabinet Disassembly 1. Remove the Back Board by removing screws 7 "a". 2. Remove 6 screws "b" securing the Light Box Assembly. 3. Disconnect connector EJ. 4. Slide the Light Box Assembly out of the cabinet.

  • Page 9: Servicing The Lenticular Screen And Fresnel Lens

    MODEL: WT-42311 / WT-A42 SERVICING THE LENTICULAR SCREEN AND FRESNEL LENS CAUTION: Wear gloves when handling the Lenticular Screen and Fresnel Lens. This prevents cuts and finger prints. Do not place Fresnel Lens in the sun. This may cause fire and heat related injuries.

  • Page 10: Servicing Pcbs

    MODEL: WT-42311 / WT-A42 SERVICING PCBs Accessing The Main Chassis In the VK20 chassis, the Main Chassis is located in front of the CRTs. Use the following procedure to access the Main Chassis. 1) Remove the Light Box Assembly, refer to the Cabinet Rear Disassembly.

  • Page 11: Pcb Locations

    MODEL: WT-42311 / WT-A42 PCB Locations Major Parts Locations Page 11...

  • Page 12: Crt Replacement

    MODEL: WT-42311 / WT-A42 ANODE LEAD REMOVAL CAUTION: To prevent damage, the following procedure must be used when removing an Anode Lead from the Flyback Transformer. 2) While holding the lead down rotate 1) Push the Anode Lead down. the lead 90º counter clockwise.

  • Page 13: Pcb-Doubler-3 (Output)

    MODEL: WT-42311 / WT-A42 Note: The 4 spring-loaded screws shown in Fig 2 and labeled as "DO NOT REMOVE", should not be loosened under any circumstance. Doing so will break the seal between the CRT and the CRT-Spacer, causing leakage of the CRT Coolant.

  • Page 14: Pcb Layout Diagrams

    MODEL: WT-42311 / WT-A42 1. Carefully position the replacement CRT and fasten in place using 4 screws "c". [Figure 2] 2. Install the Deflection Yoke on the CRT neck. [Figure 3] 3. Install the Lens that was removed in step 5 of Removal of the CRT.

  • Page 15: Electrical Adjustments

    MODEL: WT-42311 / WT-A42 ELECTRICAL ADJUSTMENTS Note: Perform only the adjustments required. Do not attempt an alignment if proper equipment is not available. 1. Test Equipment • Oscilloscope (Unless otherwise specified, use 10:1 probes) • Signal Generator (both SD and HD capable) •...

  • Page 16: Initial Setup

    MODEL: WT-42311 / WT-A42 3. Initial Setup A. Option Menu Setup Follow the steps below for the initial set-up: 1. Select the "MENU" display by pressing the "MENU" button once. 2. Press the number buttons "2", "2", "7", "0" in sequence to select the "OPTION MENU" display.

  • Page 17: Led Indicator Diagnostics

    MODEL: WT-42311 / WT-A42 Items in the table below are set to following after Initalization. AV Memory Initial Settings Ant-A NTSC COMP. A/V Memory Ant-B 1/2/3 Contrast Brightness Sharpness Color Tint High High High High Color Temp. Stnd. Stnd. Stnd.

  • Page 18: Circuit Adjustment Mode

    MODEL: WT-42311 / WT-A42 5. Circuit Adjustment Mode Except for the following, all adjustment items must be performed using the remote hand unit. • Lens Focus FUNCTION CHASSIS • Electrostatic Focus A. Activating the Circuit Adjustment Mode Video Chr 1. Press the "MENU" button on a remote hand unit.

  • Page 19: Convergence Adjustment Mode

    MODEL: WT-42311 / WT-A42 D. Saving Adjustment Data Press “ENTER” to save adjustment data in memory. The character display turns red for approximately one second in this step. Note: If the circuit adjustment mode is terminated without pressing “ENTER”, changes in adjustment data are not saved.
  • Page 20 MODEL: WT-42311 / WT-A42 Use the VIDEO button to select an item. Use the ADJUST buttons to change data. Note: When Item “1 HVOL” is selected the screen goes black except for the data display. This occurs since a black screen is required when making the HV Regulation adjustment.

  • Page 21: Adjustment Items List

    MODEL: WT-42311 / WT-A42 Cursor Coordinates Specific intersections in the Crosshatch are assigned vertical and horizontal coordinates. These are shown in the preceeding diagram. The Cursor can only be moved to those positions that have coordinates assigned. If the Cursor is at coordinates outside the screen area, the Cursor will not be visible.
  • Page 22 MODEL: WT-42311 / WT-A42 Deflection Jungle Menu-2-2-5-7 Item# Abbrev. Description Range HD Others HWID Width 0~63 HKEY Horiz. Keystone 0~63 EWPT Top EW-PCC 0~63 VHGT Height 0~63 VLIN Vert. Linearity 0~15 VSCN Vert. S Corr. 0~15 VPOS Vert. Position 0~63...

  • Page 23: Crt Installation

    MODEL: WT-42311 / WT-A42 COARSE CONV GREEN (MENU-2-2-5-9-5) Abbrev. Description HSTA Horiz. Position VSTA Vert. Position SKEW Skew (Y axis) TILT Tilt (X axis) HWID Width HLIN Horiz. Linearity SPCC Side PC Corr. HKEY Horiz. Keystone TBPC Top/Bottom PC -180...

  • Page 24: Adjustment Test Points

    MODEL: WT-42311 / WT-A42 Adjustment Test Point Locations Test Points DT pin 3 - HV Adjust DT pin 6 - Ground DT pin 7 - 12 Volts DT pin 8 - ACL JA pin 14- Main Picture (Y) JA pin 18 - Main Color (Cr)

  • Page 25: Adjustment Procedures High Voltage Regulation

    MODEL: WT-42311 / WT-A42 Purpose: To set the CRT Anode voltage. [HV Circuit] Dark Picture Symptom: 1. HV Regulation Measuring DC Voltmeter Note: This adjustment must be rechecked following Adjustment 9 CRT Cutoff. Instrument Test Point DT connector pins 3 & 6 1.

  • Page 26: Main/Sub Color Level

    MODEL: WT-42311 / WT-A42 Purpose: To match the sub picture color to that of the main picture. [Video Circuit] Symptom: 3. Main/Sub Color Level Main and sub pictures colors differ. Measuring Oscilloscope Instrument 1. Supply an NTSC signal to an External Video Input.

  • Page 27: White Balance (Ntsc)

    MODEL: WT-42311 / WT-A42 Purpose: [CRT Circuit] To set the CRTs white level in the NTSC mode. Symptom: 5. White Balance (NTSC) Monochrome has a color tint. Measuring Note: Use the “FORMAT” button to activate the Expand mode (full screen).

  • Page 28: Black Level

    MODEL: WT-42311 / WT-A42 Purpose: [Video Circuit] To set the black level of the picture. Excess or insufficient brightness. Symptom: 7. Black Level Measuring ----- Instrument 1. Supply a Monoscope signal to a Video Input. 2. Activate the Adjust Mode, Video Chroma Function.

  • Page 29: Dynamic Focus Preset

    MODEL: WT-42311 / WT-A42 [Focus Circuit] Purpose: To improve edge focus. 9. Dynamic Focus Preset Symptom: Poor focus at the edges of the screen. Measuring ----- 1. Supply a Monoscope signal to a Video Input Instrument 2. Activate the Convergence Mode.

  • Page 30: Electrostatic Focus

    MODEL: WT-42311 / WT-A42 [CRT Circuit] Purpose: To set electrostatic focus to the optimum point. Symptom: Poor focus. 11. Electrostatic Focus Measuring ----- Instrument Note: This adjustment must be performed after the Sub Contrast adjustment. Test Point ----- Static Focus Adjustment ------ Ext.

  • Page 31: Deflection/Convergence Geometry Presets

    MODEL: WT-42311 / WT-A42 [Conv/Defl] To preset data controlling raster geometry Purpose: 13. Geometry Preset Raster distortion. Symptom: ----- Measuring Note: This procedure is usually only necessary if an E2PROM is replaced in the TV Instrument Control or Convergence circuits.

  • Page 32: Deflection Circuit Geometry Adjustments

    MODEL: WT-42311 / WT-A42 To set the height, width and linearity of the raster. Purpose: [Deflection Circuit] Symptom: Incorrect height, width and/or linearity. 14: Deflection Geometry Height & Width Adjustments Measuring Instrument ----- Preliminary: Test Point 1. DO NOT change the initial values for “#8 VLIN” in the Defl. Jungle Function.

  • Page 33: Convergence Circuit Geometry Adjustments

    MODEL: WT-42311 / WT-A42 [Convergence Circuit] Purpose: To set the Convergence circuit geometry adjustments. 15. Convergence Geometry Symptom: Raster distortion at the top, bottom or sides of the picture. Adjustments ----- Note: Deflection Circuit Geometry must be performed before this adjustment.

  • Page 34: Centering And Static Convergence

    MODEL: WT-42311 / WT-A42 Purpose: [Convergence Circuit] To converge red, green and blue at the center of the screen Symptom: 16. Centering and Static Color edging over the entire picture. Convergence Measuring Instrument ----- Preliminary Test Point Degauss the shield cover and bracket unit of the CRT assembly and chassis.

  • Page 35: Coarse Convergence Adjustments

    MODEL: WT-42311 / WT-A42 [Convergence Circuit] Purpose: To converge red and blue on green at the edges of the screen. 17. Coarse Convergence Symptom: Color edging at the top, bottom and sides of the screen. Measuring SD mode ----- Instrument 1.

  • Page 36: Fine Convergence Adjustments

    MODEL: WT-42311 / WT-A42 Purpose: [Convergence Circuit] To converge red, green and blue at the edges of the screen Symptom: 18. Fine Convergence Color edging at the edges of the picture. Measuring ----- Instrument SD Fine Adjustment Test Point ----- 1.

  • Page 37: Chip Parts Replacement

    MODELS: WT-42311 / WT-A42 CHIP PARTS REPLACEMENT Some resistors, shorting jumpers (0 Ohm resistors), Chip Parts Removal (Transistors) ceramic capacitors, transistors and diodes are chip parts. Melt the solder of one lead and lift the side of The following precautions should be taken when replacing that lead upward.

  • Page 38: Replacement Parts

    MODELS: WT-42311 / WT-A42 REPLACEMENT PARTS Parts Ordering To expedite delivery of replacement parts orders, specify the following: Model Number/Serial Number Part Number and description Quantity Note: Unless complete information is supplied, delay in processing of orders will result. Critical and Warranty Parts Designation Critical Electrical Components are indicated by Bold Type in the Parts List, and in the schematic diagrams by shading.

  • Page 39: Quick Reference List

    MODELS: WT-42311 / WT-A42 QUICK REFERENCE FOR COMMON REPLACEMENT PARTS CRT ASSEMBLIES PART NO. DESCRIPTION 251C219010 ASSY-CRT-RED 251C219020 ASSY-CRT-GREEN 251C219030 ASSY-CRT-BLUE REMOTE CONTROL 290P111010 REMOTE CONTROL HIGH VOLTAGE / DEFLECTION COMPONENTS Q5A31 261P122010 HORIZ-OUT 2SC5778 Q5A51 261P082010 HV-OUT 2SK2771-O1R T5A51...

  • Page 40: Service Parts List

    MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description TUBES IC7E10 275P769010 IC-C-MOS - TC74AC157FT IC7E11 275P769010 IC-C-MOS - TC74AC157FT 251C219010 ASSY-CRT-RED...
  • Page 41 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description Q5A31 261P122010 TR - 2SC5778 D5A53 264P489010 DIODE - RD16FB1 Q5A32 261P127010 TR - 2SK2774-01...
  • Page 42 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description COILS L6K08 409P777080 EMI-F-CHIP - BLM21P221S L6K09 409P777080 EMI-F-CHIP - BLM21P221S L1A30 321C114010...
  • Page 43 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description L7HA5 409P777080 EMI-F-CHIP - BLM21P221S LC6K00 409P875090 EMI-F-CHIP - ELKE103FA L7HA6 409P777080 EMI-F-CHIP - BLM21P221S...
  • Page 44 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description VARIABLE RESISTORS R4B16 109P095010 R-METAL-LIN - 1/4W 5.1K-J R4B17 103P711090 R-CARBON - 1/4W 330-J...
  • Page 45 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description R5A53 103P713070 R-CARBON - 1/4W 10K-J R5H19 103P713070 R-CARBON - 1/4W 10K-J R5A54...
  • Page 46 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description R6G07 103P711030 R-CARBON - 1/4W 100-J R9A24 103P142070 R-CARBON - 1/2W 1.5K-J R6G09...
  • Page 47 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description CH50V 220P-J 154P344030 B16V 1M-K 141P134070 C2N17 181P355000 C-ELEC - 50V 0.47M-M CH50V 270P-J...
  • Page 48 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description C3E02 181P355010 C-ELEC - 50V 1M-M C5A56 181P355080 C-ELEC - 50V 47M-M C3E04...
  • Page 49 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description C6Y56 181P352070 C-ELEC - 16V 470M-M C9A29 142P010090 C-CER - B500V 470P-K C6Y59...
  • Page 50 MODELS: WT-42311 / WT-A42 [#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description 490P220030 LENS - ALL COLORS PRINTED CIRCUIT BOARDS 494D006010 MIRROR - 42" 930B888001...

  • Page 51: Screen Parts List

    MODELS: WS-42311 / WT-A42 [[#] Model Legend: (1) WT-A42, (2) WT-42311 Ref # Part # Part Name & Description Ref # Part # Part Name & Description SCREEN ASSEMBLY PARTS 641B942010 HOLDER-SCREEN-T - . 750A434010 FRONT-MASK 641B943010 HOLDER-SCREEN-S 491P136010 SCREEN-LENTICULAR - LENTI-4 760D628070 DIAMOND SHIELD - 42"...

  • Page 52: Power Supply

    MODELS: WT-42311 / WT-A42 POWER SUPPLY Page 52...

  • Page 53: Video / Color Signal Path

    MODELS: WT-42311 / WT-A42 VIDEO / COLOR Page 53...

  • Page 54: Sync Signal Path

    MODELS: WT-42311 / WT-A42 Page 54...

  • Page 55: Deflection / Hv

    MODELS: WT-42311 / WT-A42 DEFLECTION / HV Page 55...
  • Page 56 MODELS: WT-42311 / WT-A42 HV REGULATION Page 56...

  • Page 57: X-Ray Protect

    MODELS: WT-42311 / WT-A42 X-RAY PROTECT Page 57...

  • Page 58: Sound Signal Path

    MODELS: WT-42311 / WT-A42 SOUND SIGNAL PATH Page 58...

  • Page 59: Convergence

    MODELS: WT-42311 / WT-A42 Page 59...

  • Page 60: Control Circuitry

    MODELS: WT-42311 / WT-A42 CONTROL CIRCUITRY Page 60...
  • Page 61 2002 2002 2002 2002 2002 Service MITSUBISHI ELECTRIC Manual PROJECTION TELEVISION VK20 CHASSIS WT-42311 WT-A42 CAUTION: Before servicing this chassis, it is important that the service person read the "SAFETY PRECAUTIONS" and "PRODUCT SAFETY NOTICE" in Part 1 of this manual.
  • Page 69 WT-42311 WT-A42 R7A39 Not Used...
  • Page 72 PWB-UNI IC6K00 IC6L00 IC6M00 CXA3506R S1L60283F30C100 CXD2309AQ ASIC...

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