MITSUBISHI DIGITAL ELECTRONICS AMERICA, INC.
9351 Jeronimo Road, Irvine, CA 92618-1904
Copyright © 2002 Mitsubishi Digital Electronics America, Inc.
All Rights Reserved
CAUTION:
Before servicing this chassis, it is important that the service person read the "SAFETY PRECAUTIONS" and
"PRODUCT SAFETY NOTICE" contained in this manual.
MITSUBISHIELECTRIC
Service
Manual
2002
2002
2002
2002
2002
· Weight and dimensions shown are approximate.
· Design specifications are subject to change without notice.
PROJECTION TELEVISION
V20B CHASSIS
SPECIFICATIONS
· Power
: AC 120V, 60Hz
240W (Except WS-73411)
275W (WS-73411 Only)
· Frequency
: VHF
54 ~ 470MHz
Range
UHF 470 ~ 806MHz
· Antenna Input
: VHF/UHF 75
unbalanced
·
CRT Size
: 7 inches
·
High Voltage
: 32.0kV (at 0A)
·
Weight / Cabinet Demensions
· Speaker
: [VS-A50]
Two 4" round, full range (8
5W)
: [WS-A48 / WS-A55 / WS-A65]
Two 5" round, full range (8
10W)
· Input Level
: VIDEO IN JACK (RCA Type)
1.0Vp-p 75
unbalanced
: AUDIO IN JACK (RCA Type)
-4.7dBm 43k
unbalanced
: S-VIDEO IN JACK (Y/C separate)
Y=1.0 Vp-p C=0.286Vp-p(BURST)
75
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 75
(RCA Type)
Pr, Pb: 700mV 75
H, V: 3.0Vp-p 75
· Output Level
: VIDEO OUT JACK (RCA Type)
1.0Vp-p 75
unbalanced
: AUDIO OUT JACK (RCA
Type)
-4.7dBm 4.7k
unbalanced
V20B
MODELS
WS-A48
VS-A50
WS-A55
WS-A65
Model
Weight
Height Width
Depth
VS-A50
200 lbs
50.3"
42.4"
23.6"
WS-A48
171.5 lbs
49"
44.5"
23"
WS-A55
237 lbs
50"
50.6"
26.3"
WS-A65
326.5 lbs
61.9"
59"
28.1"
Page 3
MODELS: VS-A50 / WS-A48 / WS-A55 / WS-A65
INTRODUCTION ................................................................................................................................5
PRODUCT SAFETY NOTICE ............................................................................................................. 5
SAFETY PRECAUTIONS ................................................................................................................... 6
CABINET DISASSEMBLY
WS-A48 (Front View) .............................................................................................................7
WS-A48 (Rear View) .............................................................................................................. 8
VS-A50 / WS-A55 / WS-A65 (Front View) ............................................................................. 9
VS-A50 / WS-A55 / WS-A65 (Rear View) ............................................................................ 10
SERVICING THE LENTICULAR SCREEN AND FRESNEL LENS
Lenticular Screen and Fresnel Lens Removal ......................................................................... 11
VS-A50 / WS-A55 / WS-A65 ............................................................................................... 11
WS-A48 ............................................................................................................................... 12
Lenticular Screen and Fresnel Lens Installation .................................................................... 13
CABINET SEPARATION
WS-A65 ............................................................................................................................... 14
SERVICING THE DIAMONDSHIELDTM r
DiamondShieldTM Removal & Installation ....................................................................................... 15
SERVICING PCBs
Chassis Removal .......................................................................................................................... 16
PCB Locations .............................................................................................................................. 16
Main Components Location ........................................................................................................... 16
Second Anode Lead Removal ........................................................................................................ 17
CRT REPLACEMENT
CRT Removal ................................................................................................................................17
CRT Installation ............................................................................................................................ 18
ELECTRICAL ADJUSTMENTS
Test Equipment ............................................................................................................................. 20
Initial Setup ................................................................................................................................... 21
LED Indicator Diagnostics ............................................................................................................. 22
Circuit Adjustment Mode ............................................................................................................... 23
Convergence Adjustment Mode ..................................................................................................... 24
Adjustment Items List ................................................................................................................... 26
Adjustment Test Points ................................................................................................................. 29
Adjustment Procedures
High Voltage Regulation ....................................................................................................... 30
Main/Sub Y Level ................................................................................................................. 30
Main/Sub Color Level ........................................................................................................... 31
CRT Cutoff ........................................................................................................................... 31
White Balance (NTSC) ......................................................................................................... 32
White Balance (HD) ............................................................................................................. 32
Black Level .......................................................................................................................... 33
Sub Contrast ....................................................................................................................... 33
Dynamic Focus Preset ........................................................................................................ 34
Lens Focus .......................................................................................................................... 34
Electrostatic Focus & Alignment Magnet Adjustment ........................................................... 35
CONTENTS
Page 4
MODELS: VS-A50 / WS-A48 / WS-A55 / WS-A65
On Screen Display Character Position ................................................................................. 35
Deflection/Convergence Geometry Presets .......................................................................... 36
Deflection Circuit Geometry Adjustments ............................................................................. 37
Convergence Circuit Geometry Adjustments ........................................................................ 38
Centering and Static Convergence ........................................................................................ 39
Coarse Convergence Adjustments ........................................................................................ 40
Fine Convergence Adjustments ............................................................................................ 41
CHIP PARTS REPLACEMENT ......................................................................................................... 42
REPLACEMENT PARTS
Parts Ordering .............................................................................................................................. 43
Critical and Warranty Parts Designation ........................................................................................ 43
Parts Tolerance Codes .................................................................................................................. 43
Replacement Part Notes
When replacing the RF-Switch or PCB-SIGNAL ................................................................... 43
When replacing the EEPROM .............................................................................................. 43
Quick Reference List .................................................................................................................... 44
Service Parts List .......................................................................................................................... 45
Screen Parts List .......................................................................................................................... 56
CIRCUITRY BLOCK DIAGRAMS
Power Supply ............................................................................................................................... 58
Video / Color Signal Path .............................................................................................................. 59
Sync Signal Path .......................................................................................................................... 60
Deflection / HV .............................................................................................................................. 61
X-Ray Protect ............................................................................................................................... 62
HV Regulation ............................................................................................................................... 63
Sound Signal Path ........................................................................................................................ 64
Convergence ................................................................................................................................. 65
Control Circuitry ............................................................................................................................ 66
Section 2 .... Schematic Diagrams
SCHEMATIC DIAGRAMS
Overall Block Diagram ................................................................................................................... 1
PCB-MAIN ..................................................................................................................................... 2
PCB-POWER ................................................................................................................................. 3
PCB-TERMINAL (Input Sw) ............................................................................................................. 4
PCB-TERMINAL (3DYC / Decoders) ............................................................................................... 5
PCB-SIGNAL-1 (AV I.O) .................................................................................................................. 6
PCB-SIGNAL-2 (Micro) ................................................................................................................... 7
PCB-SIGNAL-3 (VCJ) ..................................................................................................................... 8
PCB-SIGNAL-4 (Convergence Generator) ........................................................................................ 9
PCBs - FRONT / CONTROL / CRT / PREAMP ............................................................................. 10
PCB-2HDW-1 (Input) ..................................................................................................................... 11
PCB-2HDW-2) (Main) .................................................................................................................... 12
PCB-2HDW-3 (Output) .................................................................................................................. 13
PCB LAYOUT DIAGRAMS ............................................................................................................... 14
Page 5
MODELS: VS-A50 / WS-A48 / WS-A55 / WS-A65
INTRODUCTION
This service manual provides service instructions for the PTV Models listed below. Service personnel should read this
manual thoroughly before servicing these chassis.
This service manual includes:
1. Assembly and disassembly instructions for the front and rear cabinet components.
2. Servicing of the Lenticular Screen and Fresnel Lens.
3. Servicing printed circuit boards (PCBs).
4. CRT replacement procedure.
5. Electrical adjustments.
6. Chip parts replacement procedures.
7. Circuit path diagrams.
The parts list section of this service manual includes:
1. Cabinet and screen parts.
2. Electrical parts.
Schematic and block diagrams of the above listed models are included in this service manual for better under-
standing of the circuitry. PCB drawings are also included for easy location of parts and test points.
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in television receivers have special safety related characteristics. These
characteristics are often not evident from visual inspection nor can the protection afforded by them necessarily be
obtained by using replacement components rated for higher voltage, wattage, etc.
Replacement parts which have special safety characteristics are identified in this service manual.
Electrical components having such features are identified by shading
on the schematic diagram and by bold
type in the parts list of this service manual. The replacement for any safety part should be identical in value
and characteristics.
V20B CHASSIS
VS-A50
WS-A48
WS-A55
WS-A65