Mitsubishi Electric VS-50111 User manual

Technical Training and
Troubleshooting Guide
T
2002
ECHNICAL
RAINING
www.mitsubishi-tv.com
V20
Chassis
V20
Chassis
V20A Chassis V20C Chassis V20C+ Chassis
VS-50111 WS-48311 WS-55411
VS-60111 WS-55311 WS-65411
WS-65311 WS-73411
Digital Ready
Projection Television
MITSUBISHI ELECTRIC
MITSUBISHI DIGITAL ELECTRONICS AMERICA, INC.

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Copyright © 2002 Mitsubishi Digital Electronics America, Inc.
All Rights Reserved
V20 Chassis
Technical Training and Troubleshooting Guide
Table of Contents
Introduction ................................................................................................................................................. i
Chapter 1 -- Chassis Layout & Servicing .............................................................................................. 1-1
Chapter 2 -- Adjustments ....................................................................................................................... 2-1
Chapter 3 -- Power Supply ...................................................................................................................... 3-1
Chapter 4 -- Control Circuitry ................................................................................................................ 4-1
Chapter 5 -- Video/Color Circuitry ......................................................................................................... 5-1
Chapter 6 -- Deflection and High Voltage Circuitry ............................................................................. 6-1
Chapter 7 -- Convergence Circuitry ...................................................................................................... 7-1
Chapter 5 -- Sound Circuitry .................................................................................................................. 8-1

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V20 Chassis Technical Training
and Troubleshooting Guide
i
Introduction
The digital ready V20 chassis is currently available in
three chassis versions, V20A V20C and V20C+. The
models using each chassis type are listed above. The
V20A has a 4:3 aspect ratio. The V20C and C+ ver-
sions have 16:9 aspect ratios. The VK20 will be intro-
duced later in this model year in a 42" wide screen for-
mat. Each chassis type has slightly different customer
features. But, for trouble shooting purposes, they are
almost identical.
The V20 chassis is similar in many respects to the V17
and V18 chassis. To simplfy the chassis, the number of
stand-up PCBs has been reduced. So, many of the same
circuits have been consolidated onto larger PCBs. This
manual will explain the major feature and circuitry dif-
ferences. For the areas that are relatively the same,
refer to the V17 or V18 Training Manual.
The Service Menu Codes have been changed for the
2002 Model Year. Table 1 lists the Menu Codes for all
recent Mitsubishi Chassis.
V 20A Cha ssi s
VS-50111
VS-60111
V 20C Cha ssi s
WS-48311
WS-55311
WS-65311
V 2 0C+ Ch a ssi s
WS-55411
WS-65411
WS-73411
VZ5 -VZ6-V15VZ7-VZ8-V16V17VZ9 -V18-V19V20
Option Menu 1-3-7-0 1-2-7-0 8-2-7-0 0-1-7-0 2-2-7-0
Adjustment Mode 2-3-5-7 1-2-5-7 8-2-5-7 0-1-5-7 2-2-5-7
Convergence Mode 2-3-5-9<4-5-6> 1-2-5-9<4-5-6> 8-2-5-9<4-5-6> 0-1-5-9<4-5-6> 2-2-5-9<4-5-6>
Table 1
CHASSIS

V20 Chassis Technical Training
and Troubleshooting Guide
ii

1-1
V20 Chassis Technical Training
and Troubleshooting Guide
Chapter 1
Chassis Layout & Servicing
Figure 1: V20 Chassis -- PCB Locations
PCB-Terminal PCB-Signal PCB-Doubler PCB-Main PCB-Power
A/V Inputs Control uPC PIP-POP Horizontal Defl. Power Supplies
A/V Selection Tuning Picture Format Vertical Defl. High Voltage
3D-Y/C VCJ 3:2 Pull Down Audio Amp. SVM
NTSC Video Conver
g
ence Line Double Conver
g
ence Amps.
Decoders Generator 480i to 480p DBF
Table 1: PCB Functions
NOTE: The locations of PCB-MAIN and
PCB-POWER have been reversed
compared to previous chassis.
As mentioned in the Introduction, the main differ-
ence between the V20 chassis and the V17 and V18
chassis is the reduction of stand-up PCBs. This means
many circuits have been moved from individual PCBs
onto larger PCBs.
Table 1 lists the major circuit functions on board each
PCB. Not listed are the Control and Front PCBs.
They function identically as in previous chassis. PCB
Locations are shown in Figure 1.

V20 Chassis Technical Training
and Troubleshooting Guide
1-2
Figure 2: V20 Chassis-- Main Component Locations
Figure 2 maps the Main Component Locations. Also
visible are the Chassis Locking Clips on the left and
right side. The Release Levers are located towards
the rear of the set from each Locking Clip. This
change in location gives greater accessibility.
The RF Connectors have been strengthened in the
V20 by adding a support plate. When replacing the
PCB-Signal or RF-Switch assembly, be sure the plate
is installed on the connectors as shown in Figure 3.
The High Voltage Anode Lead Connector has been
enhanced in the V20. Spring tension between the
lead and the FBT has been added to help secure the
connection. This changes the removal procedure.
Refer to Figure 4 for the new procedure.
Also note, the FBT and HV Block have been com-
bined into a one piece unit.
Figure 3: V20 Chassis -- RF Switch

1-3
V20 Chassis Technical Training
and Troubleshooting Guide
1) Push DOWN on the Anode Lead.
2) While holding the lead down, rotate
the lead 90º counter clockwise.
3) Carefully remove the Anode Lead
from the Flyback Transformer.
Figure 4: V20 Chassis -- HV Anode Lead Removal Procedure
Self Diagnostics
The “Power ON LED” provides an indication of
the sets operation, and the possible cause of a
shutdown condition.
A. Initial Control Circuitry Check
Immediately after the TV is connected to
an AC power source:
• The LED flashes three times... indicating
the Microprocessor has initialized and is
functioning properly.
• If the LED does not flash... the Micropro-
cessor is NOT functioning.
B. Error Code Operational Check
Pressing the front panel “INPUT” and
“MENU” buttons at the same time, and
holding for 5 seconds, activates the Error
Code Mode. The LED flashes denoting a
two digit Error Code, or indicating no
problem has occured since the last Power
Off.
Error Code Description
12 No error has occurred.
21 X-Ray Protect circuit.
22 Short Protect circuit.
23 Horizontal Deflection failure.
24 Vertical Deflection failure.
Note: The front panel buttons must be used,
NOT those on the Remote Control.
• The number of flashes indicates the
value of the MSD (tens digit) of the
Error Code.
• The flashing then pauses for approxi-
mately 1/2 second.
• The LED then flashes indicating the
value of the LSD (ones digit) of the
Error Code.
• The Error Code is repeated a total of 3
times.
Example: If the Error Code is “24”,
the LED will flash two times, pause,
and then flash fourtimes.
C. Error Codes
The Error Code designations indicating a
malfunction, or no malfunction, are listed
below:

V20 Chassis Technical Training
and Troubleshooting Guide
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