MITSUBISHI V19, V21 Service Manual

MITSUBISHI DIGITAL ELECTRONICS

V19 / V21

PWB Level

Troubleshooting Guide

V19 / V21

PWB Level Troubleshooting Guide

9351 Jeronimo Rd.

Irvine, CA 92618

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Table of Contents

V19 / V21 PWB Level Troubleshooting Guide

Introduction iii

Printed Circuit Board Layout 1

TROUBLESHOOTING

Shut-Down Problems 2

X-Ray Protection Failures 3

Horizontal Deflection Failures 4

Vertical Deflection Failures 5

TV Microprocessor Diagnostics 6

Color or Video Failures 7

QUICK REFERENCES

Power Supply 8

Main Board 9

Deflection Jungle 9

3DYC Module 10

CRT Drive 10

2HDW Module 11

Digital Module Assembly 12

Convergence Module and IC 13

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WAVEFORMS

KH, DR, DQ Connectors 14

DQ, EF Connectors 15

EF, RM, EA Connectors 16

EA, EB, VA Connectors 17

VA, DB, VD Connectors 18

VD Connector & IC8C01 19

IC8C01 20

IC8C01, IC9A20, IC9A50 21

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V19 / V21 PWB Level Troubleshooting Guide

Introduction

The purpose of this V19 / V21 PWB Level Troubleshooting Guide is to assist the servicer to quickly identify common

chassis test points, and to facilitate efficient servicing procedures in the field or service shop / depot. It is intended for use in tandem with the Service manual as an aid to troubleshooting a set. Included are many major DC voltage measurements and AC waveforms pertinent to proper operations of the chassis. In addition, troubleshooting procedures are provided for some common service issues a Technician may encounter.

This guide is not intended to be used as a resource for technical training, circuit analysis, or adjustment procedures. Refer

to the V19 / V21 Technical Training guide and/or the Service manual which includes all schematics, parts lists, and

adjustment procedures for these purposes.

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V19 / V21 PWB Level Troubleshooting Guide

DBF-PCB

Printed Circuit Board Diagram

KH KH

KKKA

SVM-PCB

Jungle Module

KFKF

IC9A50

IC8C01

Heatsink As sy

Generator

Convergence

2HDW-PCB

Shield

Assembly

3DYC-PCB

Shield

IC9A20

Assembly

PCB-Signal PCB-Power PCB-Main

PCB Terminal

1111

V19 / V21 PWB Level Troubleshooting Guide

Troubleshooting

Shut-Down

Problems

Initial

Front Panel

L.E.D. Status

Power

Applied

Off

Problem in

Standby Power

Supply or TV

Microprocessor

is not running

Check Standby

Supplies

Page 8

Check TV

Microprocessor

IC7A00 Page 6

Fast Blink

70 Seconds

Only

Normal

Operation

If the Light Box is removed from the cabinet without the front panel control assembly, be sure to wait 70 seconds prior to turning on the TV. There is no visual indicator to remind you of the delay while the DM is in the process of booting.

If Set Shuts

down after

power-up,

continue Shut-

Down

troubleshooting

Fast Blink

Continuous

Microprocessor is

running, DM

failed to boot.

UnPlug Set, wait

30 seconds and

try again.

Replace DM

Assembly

Slow

Blink

Normal Operation

TV "On" Timer is

active.

If Set Shuts down upon

power-up,

continue Shut-

Down

troubleshooting

1 then 2 flashes

Normal

Operation

While the set is OFF, Press and hold the Front Panel "Device" and "Menu" Buttons for five seconds

Check the Status of the Flashing L.E.D. on the front panel

2 then 1 flash, X-Ray Protect

Problem. Go to

Page 3

2 then 2 flashes,

Short Circuit Protect. Go to Power Supply

Page 8

2 then 3 flashes,

Horizontal Deflection

failure. Go to

Page 4

2222

2 then 4 flashes,

Vertical

Deflection

failure.

Go to Page 5

Caution !

V19 / V21 PWB Level Troubleshooting Guide

Troubleshooting Shut-Down Problems

X-Ray Protect

Prior to the diagnostics of these issues, it is imperative that you disable the CRT's to prevent phosphor damage.

Do so by removing Connector SP, which removes filament voltage, or removing each CRT-PCB.

With CRT's disabled

Check HV Block

for arcing

Check Anode

Caps, Spark

Gaps on PCB-

CRT

Unit Shuts

Down

Is there HV

Arcing evident?

NoYes

Check HV

Block for short

or open

N.G. Good

Unit Now Operates

N.G.

Check High

Voltage

32 KV

Normal High

Check IC5A02 Check IC5A03

Check FBT Pin 8 (2.8 V)

Check Voltage at Cathode

of D5A57 (18.4 V)

Low

Check IC5A00 - IC5A01

Check all Peripheral

Good

Components

Normal

Check CRT-

Sockets. Check

CRT's

Replace HV

Block

Replace Main

PCB

Replace FBT

3333

Caution !

V19 / V21 PWB Level Troubleshooting Guide

Troubleshooting Shut-Down Problems

Horizontal Deflection Failure

Do so by removing Connector SP, which removes filament voltage. Also remove D5A13 on the Main PCB to disable the deflection shut-down circuitry

If Missing, Replace

PWB-Signal

Prior to the diagnostics of these issues, it is imperative that you disable the CRT's to prevent phosphor damage.

KE Connector

PWB Signal

Out Out

20 uSec / Div

2.00 V / Div

0.48 V DC

31.5 KHz

4.24 V Pk-Pk

KH Connector

PWB Main

If Missing, Replace

PWB-Main

If waveform is missing,

check pin 2 of FB connector

(PWB-Jungle)

Normal

4.4 V

Replace

PWB-Jungle

Low

Replace

PWB-Signal

Waveform

Good

Replace

PWB-Main

20 uSec / Div

2.00 V / Div

4444

31.5 KHz

7.96 V Pk-Pk

3.6 V

DQ Connector

Out

PWB Jungle

+ 17 hidden pages