SHARP VT-3428X, VT-51 Service Manual

SERVICE

MANUAL

TV/VCR COMBINATION

VIDEO TV

Chassis No.

VP-3

VT-3428X

MODELS

In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used.

FEATURES

n

W

TV/VCR Integration for Easy Operation

W

Single Built-in Tuner for Simple Operation

n

Timer Programme Setting by the On-Screen

Display

W

Auto Tracking Control

n

Full

Auto Head Cleaning System

n

On-screen Display with Menu Screen Guidance

H

Wake-Up/Sleep Timer

n

NTSC

Simple Playback

r

CONTENTS

2-way Child-Proof Lock

@To

Lock Operation Mode

@To

Lock the Power Off.

n

Ret Index with DPSS (Digital Programme Search

System)

n

Full Auto Play Function

n

Auto Repeat Playback

n

Front input terminals Audio/Video

VT-5128X

\

l

SPECIFICATIONS

l

IMPORTANT SERVICE NOTES . LOCATION OF USER’S CONTROL . DISASSEMBLY AND REASSEMBLY . ADJUSTMENT OF THE TV ELECTRICAL

CIRCUITRY . PRECAUTIONS IN REASSEMBLING . FUNCTION OF MAJOR . ADJUSTMENT, REPLACEMENTAND

ASSEMBLY OF MECHANICAL PARTS ADJUSTMENT OF THE VCR ELECTRICAL..

.

CIRCUITRY

. TROUBLESHOOTING

........................

.............

.........

.............................

MECHANICALaPARTS

............................

...................

........

.

.......

..

Page

2 3 4 6

8

15

16

18

42 45

l

OVERALL SCHEMATIC DIAGRAM

l

CHASSIS LAYOUT OF TV SECTION

.

BLOCK DIAGRAM OF TV SECTION

.

DESCRIPTION OF TV SECTION SCHEMATIC DIAGRAM

.

CHASSIS LAYOUT OF VCR SECTION

l

BLOCK DIAGRAM OF

. DESCRIPTION OF VCR SECTION

SCHEMATIC DIAGRAM

. PRINTED WIRING BOARD ASSEMBLIES . REPlACEMENT PARTS LIST .

PACKINGOFTHESET

.................

VCRSECTION

.................

........

.......

............

......

...

Page

57 59 61

65 79 81

91

97 105 134

WARNING

The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug and

power receptacle, when servicing this chassis. To prevent electric shock, do not remove cover. No user qualified service personnel.

-

serviceable parts inside. Refer servicing to

SHARP CORPORATION

/

W-3428X VT-51 28X

SPECIFICATIONS

I

Model

Reception channels

I-

VHF band

UHF band

Receiving System

AV Input

Screen 34 cm “Viewable” measured

diagonally,

Antenna input

Audio output

Speaker

Rated voltage

Rated frequency

Power consumption 77 W

Video cassette format

I

Video recording system

I

Number of Video Heads I

Video signal

(PlaybacWRecording)

Recording/playing time

Tape width

Tape speed

Operating temperature

I

Storage temperature

Weight

Dimensions

Video input

Audio input

Supplied accessories Operation manual, wireless remote control unit,

output

I

1

I

1

13.7 388(W)

kg

VT-3428X

VHF :

NZl - NZll

CATV

: Sl -

UHF :

44.25 MHz - 463.25

(VL: 45.25 - 168.25 MHz/VH: 175.25 - 463.25

471.25

MHz -

PAL B/G

90”

deflection

75

ohm unbalanced

Max.

8 cm round type x 1

AC220

50

VHS

Two rotary heads, helical scan

480

minutes max. with

12.7

x

PAL

NTSC

380(H)

:

23.39 mm/set (SP)

11.70 mm/set (LP)

:

33.35 mm/set (SP

16.68 mm/set (LP 11 .12 mm/set (EP

5°C

-20°C to

x

395(D)

mm

Vp-p,

1

.O

1.OVp-p,75ohm

Phono

jack:

0.5 Vrms, 10 kohm

Phono iack: 0.5 Vrms.

R03 (AAA)

S41

E21 - E69

MHz

885.25

MHz

PAL

51

cm “Viewable” measured

diagonally, 90’ deflection

1.5

W

pc

V -

240

V

Hz

I98W

standard

2

PAL

E-240

mm

playback only)

to

40°C

60°C

24.2

kg

510(W)

x

499(H)

75 ohm

1

kohm (54%

battery x 2

VT-51

tape

MOD)

28X

MHz)

x

483(D)

I

mm

*Design and specifications are subject to change without notice.

2

IMPORTANT SERVICE NOTES

Maintenance and repair of this receiver should be done by

qualified service personnel only.

SERVICING OF HIGH VOLTAGE SYSTEM AND PICTURE TUBE

When servicing the high voltage system,

remove static charge from it by

connecting a 10 k ohm Resistor in series with an insulated wire (such as a test probe) between picture tube

dag

and

2nd

anode lead. (AC line cord should

be disconnected from AC outlet.)

1.

Picture tube in this receiver employs integral implosion protection.

2.

Replace with tube of the same type number for continued safety.

3.

Do not lift picture tube by the neck.

4.

Handle the picture tube only when wearing shatterproof goggles and after discharging

the high voltage completely.

X-RAY

This receiver is designed so that any X-Ray radiation is kept to an absolute

minimum. Since certain malfunctions or servicing may produce potentially hazardous radiation with prolonged exposure at close range, the following precautions should be observed:

1. VT-3428X: When repairing the circuit, be sure not to increase the high voltage to more

than

25.3 kV,

VT-5128X: When repairing the circuit, be sure not to increase the high voltage to more

than

29.3 kV,

2.

m-3428X: To keep the set in a normal operation, be sure to make it function on

22.0 kV

been factory

VT-5128X:

mm-

If there-is a possibility that the high forget to check for such high voltage after the work.

3.

DO not substitute a picture tube with unauthorized types and/or brands which may cause

excess X-ray radiation.

To keep the set in a normal operation, be sure to make it function on

25.0 kV ,+ 1.5 kV

factory

(at beam 0 (at beam 0 4) for the set.

+

1.5 kV - 2.0 kv

-Adjusted to the above-mentioned high voltage. (at beam

-Adjusted to the above-mentioned high voltage.

,A)

for the set.

(at beam

1100

,A)

vo,ltage

800 fi)

in the case of the set. The set has been

fluctuates as a result of the repairs, never

in the case of the set. The set has

BEFORE RETURNING THE RECEIVER

Before returning the receiver to the user, perform the following safety checks.

1.

Inspect all lead dress to make certain that leads are not pinched or that hardware is not

lodged between the chassis and other metal parts in the receiver.

2.

Inspect all protective devices such as non-metallic control knobs, insulating fishpapers,

cabinet backs, adjustment and compartment covers or shields, isolation capacity networks, mechanical insulators etc.

3

resistor-

(REARI

I

0

n

FF

(Forward video

search) BUTTON

STOP/EJECT

BUlTON

VT-51

28X

2,

-I

REW

(Reverse video

i

. . : :

POWER

BUTTON

P

SENSOR ARE FOR REMOTE CONTROL

VIDEO INPUT JACK AUDIO INPUT JACK

NOTES:

l Use the RESET button if the

VIDEOAV

Timer, etc.) cannot be operated.

1

mode (ex.

EA ’

Program

-

REC

BUlTON

I

POWER/WAKE-UP

TIMER INDICATOR

VOLUME UP/DOWN BUTTONS

CHANNEL UP/DOWN BUl-t-ONS

f-4

1

J

AESR

l REC

VVOL

A V

CH

A

search) BUTTON

MAIN POWER SWITCH

VIDEO OUT JACK AUDIO OUT JACK

ANTENNA IN TERMINAL

VT-3428X

MAIN POWER SWITCH

(01) _J

(01)--l

0

2

0

In

c

K 51c1

vi

(1

0

z

-I 510

0

I

AUDIO OUT JACK

ANTENNA IN TERMINAL

-

The remote control lets you operate this product at a distance. Just aim the front of the remote control at the photoreceptor window situated on the front panel and press the appropriate

Inserting the Batteries

The remote control operates on two volt batteries (included). If the remote control does ‘not operate or fails to function normally due to weak batteries, new batteries can be purchased at electronics or camera stores.

Press Down

-

Battery Cover

-4-P

Slide off

l You can set clock and timer recordings using the remote control.

Slide on

0

Open the battery cover. (Remove any old

batteries that may be in the remote control.)

@

Insert

w ab tteries and match their polarities

ne

( + and - ) with the markings inside the compartment.

0

Replace the cover.

R03 (AAA) 1.5

SENSOR AREA FOR REMOTE CONTROL

Clock setting:

see SETTING THE CLOCK

Timer recording: see RECORDING WITH THE TIMER

NOTES:

l Do not subject the remote control to impact, water or excessive humidity.

l

The remote control may not function if the photoreceptor window of this product is in direct sunlight or any other strong light. If so, move the product or alter the lighting.

l Incorrect use of batteries may cause them to leak or burst. l Do not mix old and new batteries, or mix the brands used.

l

Both rechargeable and disposable batteries are available. Read the battery warnings and

do not try to recharge disposable batteries.

l Remove the batteries if the remote control will not be used for a long time.

POWER ON/OFF button (0

WAKE-UP TIMER

SLEEP

TIMER

XIANNEL

SELECT

buttons

TIMER ON/OFF button

PAUSE/STILL button

COUNTER RESET button

I)

EJECT/LOAD button

MUTE button

DISPLAY button

VOLUME ADJUSTMENT buttons

CHANNEL UP/DOWN buttons

(TRACKING buttons)

PROGRAMME button

MENU button

SET button

STOP button

SPILP button

PLAY button

FF

button I

Video Search

REW button I Reverse

Video Search

F&ward

U--3428X VT-51 28X

DISASSEMBLY AND

n

TV SECTION

1.

Remove the nine screws off the rear cover.

1.

Remove the ten screws off the rear cover. (VT-51 28X)

2.

Disconnect the F connector from the main

the anode cap and the CRT PWB unit from the CRT.

3.

After disconnect the coating earth from the CRT unit and take out the unit.

4.

Remove the two screws from the main PWB and separate the

5.

Remove the three screws from the power

(VT-3428X)

PWB

and G connector from the power

PWB

and separate the

R’EASSEMBLY

PWB

from the video unit.

PWB

(VT-51 28X)

PWB

and disconnect

from the video unit.

6

DISASSEMBLY AND REASSEMBLY

6.

Remove the CRT PWB,

the main PWB upright.

7.

Reconnect the CRT PWB. Put the main PWB and the VCR unit together as shown below. Keep the front

power switch remote control PWB, speakers and

degaussing

coil connector G and front power switch remote control

degaussing

coil connector G off position.

(Continued)

PWB.

Place

n SERVICING THE

Unhook the power PWB and place it on the left hand of the set. Set up the mother PWB as shown below.

PWBs

-Mother

FRONT

PWB

<Repairing the TV and VCR units> Unhook the VCR unit, and place it as shown here. Connect the

cables start repairing.

PWB/mechanism

(AB),

(AD) and (PC) to the mother

assembly from the

TV Unit

PWB

to

W-3428X VT-51 28X

l PRECAUTIONS

Calling the service mode

I,

(1) Place the set in the stand-by mode. (2)

Hold down the CH UP key POWER button ( bl ) of the set. Now the set is in the service mode.

Clearing the service mode

2.

(1)

There are two ways to clear the service mode. Press the MENU key on the remote control gun

(2) Or place the set in the stand-by mode again.

Display in the service mode

3.

ADJUSTMENT OF THE

TV ELECTRICAL CIRCUITRY

(CH A)

of the set for 2 seconds or longer and at the same time press the

ROM No. in the microprocessor

L-------d r-------------------~

i 1100 0100 0010 1101 I’ +VCJICdata

L---------------,,,,~

*SERVICE MODE :

*SERVICE MODE : *SERVICE MODE :

*SERVICE

*SERVICE MODE :

*SERVICE MODE : *SERVICE MODE :

*SERVICE MODE :

L---l

MODE :

01 02 03

04

05 06 07 08 09

RED

INT

GRN

INT

BLUE INT

VERTAMP VERT

LIN

VERT

POS= O-63 HOR PHAS

HI-VI

HGAlNl

+

Adjustment item Nos.

data

=

O-63

=

O-63

=

O-63

= O-63

=

O-63

=

lo-55

= O/l

/2/3

=0/l

01-l

(O-63,1 O-55,0-3, O- 1)

General adjustment items

2

*SERVICE MODE : *SERVICE MODE : *SERVICE MODE :

10

HGAlN2

11

INTSEL

12

CALKILL

T-

Ls

electable

=0/l

= O/l

=0/l

by the CH

8

Basically fixed

Variable by the VOL

Aw

key

Aff

key

SCREEN/BACKGROUND ADJUSTMENT

i/T-3428X VT-51 28X

.

1.

Screen Adjustment

1.

Receive the “AV-CH” signal. Keep the blue

background off.

2.

Reset “video adjust” mode.

t

2.

Background Adjustment

1.

Receive

PATTERN” signal.

2.

In the video adjust mode, adjust the brightness

and contrast.

8

Bright portion:

l Dark portion:

Keep the colour adjusted at “00”.

Adjusting Conditions

“WHITE BALANCE ADJUSTMENT

120

nit

20

nit

1.

Call the service mode and take the step below.

0

Screen control: Look at the control so that the

turn from “1 II to

1.

Call the service mode and take the step below.

l

Red intensity :

l

Green intensity :

l

Blue intensity :

Pick up the service mode numbers

Adjust the

12,300”K (x

The

“CA-100 Minolta

be used as a colour thermometer.

Adjusting Procedures

VCJ IC

data on the screen. Adjust the

10th

figure from left should

“0”.

To be 0 here too.

f

To turn to 0 here.

colour

temperature as follows.

=

0.272 + 0.015,

y =

CRT Color Analyzer” should

“2”

and

0.275 It 0.015)

“3”.

3.

Focus Adjustment

1.

Receive “monoscope pattern” signal.

2.

Reset the video adjust mode to have the Video

Normal Position.

1.

Adjust the focus control to have the best focus in

the areas between the pattern’s center. and its both ends.

Adjust point

9

W-3428X VT-5128X

HORIZONTAL/VERTICAL CIRCUIT ADJUSTMENT

0

Figure

0

Figure

1.

2.

I

1.

Receive “PAL monoscope pattern” signal.

2.

Reset the video adjust mode to have the Video

Normal position.

I. Call the service mode and take the steps below.

l

VERT-AMP

Select the service mode number

VERT-AMP

l

VERT-LIN

Select the service mode number

VERT-LIN

Figs. 1 and

l

VERT-POS

Select the service mode number “6”. Adjust the

VERT-POS

center of the screen. (See

l

HOR-PHAS

Select the service mode number

HOR-PHAS so that the horizontal center be at the

center of the screen. ( See

Adjusting Conditions

Adjusting Procedures

(vertical size):

“4”.

Adjust the

to have 10% overscan.

(vertical linearity):

‘5’.

Adjust the

to have optimum vertical linearity. (See

1.)

(vertical center):

so that the vertical center be at the

Fig.

3.)

(horizontal center):

“7’.

Adjust the

Fig.

4.)

~~

:

.

. . . . . . .

..--

.

:

.’

.*

i

.

‘.

.

$

-.

.

-.

.

-......-

.

‘.

.

Figure

3.

4.

‘.

:

-.

.

-.

.

‘.

:

,

a* ;

*.-

,

:

.

_

l ‘

,

:

IO

W-3428X VL5128X

PURITY ADJUSTMENT

Adjusting Conditions

1.

Before the purity adjustment, warm up the set

with beam current of more than 700

longer than 30 minutes (400 PA for the

I

a

b

model).

2.

Receive the qreen-only signal and adjust the

beam current to about 770 @I (500 fi for the model).

3.

Fully

degauss

the CRT with the

degaussing

,uA

coil.

for

14”

Figure A.

Adjusting Procedures

Notes:

Left

.

A..*.-...*.

::::::::::::::::::::~.

,

. . . . . . . . . . . .

:.~:.>:.y*.~;

::::~::::::::::::::::::::

s:~:::::::::::::::::~:::

::::::::::::::::$::::

I

:::::::::~~::::::::::::::::::

. . . . . . . . . . . . . . .

~~~,:.:.:,~.:.:.:.:.:.:.:

I

:::::::~::~~~.:~:::::

I

f

:::::::::::::::::::::::::::::::

:::::::::::~:~:::::::::

I

:::~~.:::::~:::::::::::::::::

:::~.::~.:::::~~::::~.::

~~

. . . . . . . . . . . . . . .

; ~~~~

::::::~::::::::::::::::::::::

\

::::#:::::::x:::$::.

\ :::::::::~.::::::~::::::..

“::::~::~:y$.:.~

~

Beam landing equally outwards.

Figure

B.

t

Left

. . . .

..:.:::::::::::::::::..

.::;~:~:~:; \

..:.:.:.:.:.:.:,~.:.:.:.:.:.

..:.:.:.:.:.:.:.~.:.:.:.:.:

:::::::~:::::::::::::::~~:::

:::::::::::::::::::::::::::::::

:~:::::::::::::::::::::::::::

2.. ..A........ *.5..* ..A..

;y:y$$:::::::y$$$$:

:::::::::::::::::~~::::::::::

:::::::::::::::::::::::::::::

.:.:.:.:.:.:.:.:.:.:.:.~.:.:.

:.:.I:.:.:.:.:.:.:.:.:.:.:.:.:

i.....~......................

:::::::::::::::::::::::::::::::

::::::::::::::::::::::::~:::::

:::::::::~:::::::::::::::::::

:::::::~:::::::::::::::::::::

:::::::~:::::::::~::::~:::

.:.:.ff~:.:.:.:.:.:.~:.:.:.

:.:.:.:.:.:.:.~.:.:.:.:.~

:.:.:.~.:.:.:.:.:.:.~~

:.:.:.:.:.~.:5.:.:,:.:.:.:

..:.:.:.:.:.:.:.:.:.:.:.:

vZ.*.5..~.5V

il

\

I

, ,

i 1

I

A...

/

*..

s.5.. fS%S. .. . .

.

y.:,:.:.:.*.v

Beam landing shifted to the right.

Figure

C.

Right

.

.v.*.

. .

,::$yjg::>g

..~:.:.:.:.~:.:.:.:.:.:.:

.:.>>>:.:.p:.>~.~. \

..:.:.:.:.:.:.:.:.:.:.:.:.:.:.:

:::::::~~.::::::::::~::

:::::::::::::~:::~.:::.

::~:::::::::::::::~::::::

@Jg$g$~~ g$$J#jgg:$ ::::::::~::::::::::::~:::::::

:::::::::::::::::::::::::::::::

:::::::~::::::::::::::::::::: ~~~~.:.

:::::::::::::::::::::~::::~::

.~.:.>‘:.:.~.~.;.~.:.:.~.

:.:.:.:.~.:.:.~.:.:.:.:.:

::::::;::::::::::::::::::::::::

:~:::~:::::~.::::::~.:::::::;

.:.~:,~~:.~..~X.:.:.

s::~::::::::::::::::~::::

13

\

1

I

,

I

1

I

::::::y$::::::::::::::::

.7...5......,.....5.,

I

. . . . . . . . . . . .

/

v.;.:.:.~

,

l

Static convergence should be roughly adjusted.

l

The purity magnet should be positioned where the magnetic field is zero.

Adjustment: During the adjustment, keep the set facing the east.

1.

Observe the spots “a” and

with a microscope. Adjust the purity magnet to have these spots at the specified landing

positions.

2.

If the right and left spots are

outwards from their landing positions (shown in

Fig.

B),

push the deflection yoke forwards for

proper positioning.

3.

If both the spots are shifted to the right or left

(shown in Figs. C and angle of the purity magnet for proper

positioning.

4.

Make sure that the center spot

and left spots are in their specified landing

positions. Check the four corners of the CRT

screen.

See if all the landing positions are

satisfactory with the Rank “B” specifications.

5.

If any

colour

other than green appears, pull the deflection coil backwards. Landing too outwards: Deflection yoke to push

“b”

(shown in Fig. A)

dqually

D),

adjust the opening

as

deviated

well as the right

forwards.

Left

.

A55..

.

:::::::::::::~~::::..

/ .5..55............55

.:,:.:.:.:.:.:f.:.:.:.:.~.

~:.v.-.~...*

. . . . . . . . . . . . . .

>:.f:.:*:.:.:.:.>:.~.:.:.

;

~~~~

. . . . . . . . . . . . . . z.

.:e:.:.>:.:.:.:.:.:.:.>:.:.:.

1 .r:‘:‘:‘:‘:‘:‘:‘:‘:‘:‘:’

. . . . . . . . . . . . . . .

.

. . . . . . . . . . . . . . .

:.~.:.:.~.:.:.~.:.:.:.:.:

. . . . . . . . . . . . . . .

.

. . . . . . . . . . . . . . .

*...*A. ..,.........A.......

I

. . . . . . . . . . . . . . . .

.:.:.:.:.:.:.:.>:.:.:.:.:.:.:.

. . . . . . . . . . . . . . . .

.:.:.:.:.:.:.:.:.:.:.:.>:.:.:.

I

:.~.:.:.>:.:.:.:s.:.~.:.:

. . . . . . . . . . . . . . .

I

:.~:.:.:.:.:.:.:.:.:.:.:.f:.:

.:.:.:.:.:.:.:.:.:.:.:.:.:.:...

I

:.~.:.:.~:.:.:.:.:.:.:.:::

. . . . . . . . . . . . . . .

:*:‘:.:.:.:.:.:.:.:.:.:.:.:.:..

.:.:.:.~.:.:.:.:.:.:.:,p:

. . . . . . . . ...*.....

... .

. . . . .

.

. . . . . . . . . .... . . .

:.x.:.:.>:.

. . . . . . . . . . . . . . .

;

\

\ ::pJ:$.:$#~..*.

[fl

.

.:.:.:.:‘:.:.:.:.~:.:.:.>:

:.~.:.:.:.:.:.:.:.:.:.:.:.:.

::$::::::p+:.:.:.:.:... .::~~:$::*$.J$.~

. . . . .

Right

Landing too inwards : Deflection coil to backwards.

6.

Receive the monoscope pattern signal.

7.

Set the raster rotation at

“0”

position with the set

facing the east.

Adjustment error: 0 + 2 mm

8.

Tighten up the deflection coil screws.

Tightening torque:

11 +

2 kg

pul

I

Beam landing shifted to the left.

Figure

D.

11

VT-3428X VT-51 28X

CONVERGENCE ADJUSTMENT

Adjusting Conditions

RGB

This adjustment should be performed after

the purity magnet adjustment.

1.

Receive the crosshatch pattern signal.

2.

Set the brightness and contrast controls to the

5/l 0 and 1 O/l 0 positions, respectively.

Figure a.

RGB

Figure

c.

Wedge

4-pole

w----------~--L

..I.......... * . . . . *

“a”

magnet

6-pole

f

Figure

magnet

b.

BGR

:

I

..I..... .‘.

.

:

I

.

: I ’

I

.

I

*

-

I

.

*I

d.

,100"

C"

CRT neck

.

I

Adjusting Procedures

STATIC CONVERGENCE

1.

Adjust the opening angle of the

and rotate the magnet to impose the blue line over the red one.

2.

Adjust the opening angle of the

and rotate the magnet to impose the green line over the blue one.

4-pole

6-pole

magnet

DYNAMIC CONVERGENCE

3.

Take the following steps for dynamic

convergence at the edges of the CRT screen.

l

Convergence in Fig a :

Insert the wedge “a” deflection coil upward for correct convergence.

l

Convergence in Fig b :

Insert the wedges he deflection coil downward for correct convergence.

l

Convergence in Fig c :

Insert the wedge deflection coil rightward for correct convergence.

l

Convergence in Fig d :

insert the wedge deflection coil

4.

Stick the above wedges on the CRT, and apply

glass tape over them.

5.

Apply lacquer to the deflection yoke screw, the

magnet unit (consisting of purity,

pole magnets)

leftward

and’the

Finally receive the red-only signal to make sure there is no mixture with any other same with the blue-only signal.

in position, and tilt the

“b”

and

“c’

in position, and tilt

“c”

deeper, and tilt the

“b”

deeper, and tilt the

for correct convergence.

4-pole

magnet unit screw.

colour.

and

6

Do the

Purity magnet

L

3

Lacquer

12

1.

A/V Output Checking

VT-3428X VT-51 28X

PERFORMANCE CHECK

Adjusting Point

1.

w

output

(J401)

1.

I

2.

A/V Input Checking

lANinput

(J802 1)

Receive the

modulation).

2.

Add a 75 ohm terminal resistor to the video output terminal.

3.

Add a

The output levels are as follows.

Note:

Make sure the video and audio outputs are as specified.

1.

Receive the

2.

Feed the external video and audio signals via the

3.

Using the CH

signals are being properly received. (The AV mode is available somewhere between

lo-kohm

Video output: Audio output:

lch and 40

colour

terminal resistor to the audio output terminal.

colour

Am

key, call the AV mode and make sure the external video and audio

(max) ch.)

Adjusting Conditions / Procedures

bar signal

1

Vp-p +

2.61Vp-p +

bar signal.

(100%

3 dB

(0.71-l .41 Vp-p)

3 dB

(1.85-3.69 Vp-p)

white

colour

A/V

front jacks.

bar, audio : 400 Hz, 100%

t

f

3.

Protector Performance Checking

Protector

Performance

4.

Beam Protector Performance Checking

Beam Protector Performance

1. Receive the monoscope pattern signal.

2.

Apply

3.

Feed 25V in the same way and make sure the protector is activated.

1.

Receive the monoscope pattern signal.

2.

Ground any of the R, G and B cathodes on the CRT PWB.

3.

Make sure the protector is activated immediately.

20V

from the constant-voltage power supply to the cathode of

symbol on the

Note:

To reset the protector, press the

Note:

To reset the beam protector, press the RESET key.

PWB)

and make sure the protector is not activated.

RESETkey.

D607 (TP603:

no

13

W-3428X VT-51 28X

PERFORMANCE CHECK

5.

Blue Background Checking

Adjusting Point

1.

Blue background

c

6.

Record Index Checking

Record index

In the SET UP mode, select the BLUE SCREEN function.

2.

Turn on the function. With any signal input,

Make sure also that the audio is mute.

3.

Turn off the function and make sure the blue background disappears.

1.

In the SET UP mode, select the

2.

Turn on the function to make recording. (Make sure the clock has been preset.)

3.

Check the recorded contents.

Note:

Make

sure

the channel and time

(Continued)

Adjusting Conditions / Procedures

make sure the background is blue.

REC

INDEX function.

are

recoded.

14

PRECAUTIONS IN REASSEMBLING

VT-3428X VT-51 28X

MOUNTING THE

Initial setting is indispensable

made in two ways; electrical and mechanical.

CASSETTE

before placing the cassette controller in the mechanism. The initial setting is

CONTROLLER

Electrical setting:

Make a short-circuit between TP8804 and TP8805, both located at the center on your side on VCR with a 22 ohm resistor and be sure that the mechanism is back to its initial setting position the cassette controller in position. (This method is used when the mechanism has been already set on its

PWB.)

(*l).

Now place

PWB,

Mechanical setting:

Cassette control

r----

COUPLING THE MECHANISM TO THE

Match the mechanism’s projections with the two symbols (round reference and oval sub-reference) on the

VCR PWB. Place the mechanism straight down in position with due care so that the mechanism chassis’s

outer edges should not damage any parts nearby.

Tighten up the two screws (one for fixing the mechanism and the head amplifier shield, the other on the

VCR

PWB’s

soldering side and located near the loading motor) to fix the mechanism and VCR PWB. Reconnect the

PWB.

FFC

cables

(EB, EF

and EH) and harnesses (ED and

drive gear

Phase matching point

PWB

EG)

between the mechanism and VCR

Turn the loading motor’s

pulley feed gear using a screwdriver and be sure that the mechanism is

back to its initial setting

position the cassette controller in

position. (This method is applicable for the

mechanism alone.)

(*l).

Now place

Parts to pay attention to:

Start and end

Record tip switch:

Take special care of the MC-EC connector

(board

and VCR

to

PWB.

.sensors:

Q8803,Q8804

58801

board) between

the mechanism

W-3428X VT-5128X

I

t

FUNCTION OF MAJOR MECHANICAL PARTS

19

Drum Motor

20

Drum

Full Erase Head

Ass’y

Supply Pole Base

Ass’y

Main Supply Brake Lever

Tension Arm

Ass’y

Ass’v m

Auto Head Cleaner

f

P

/

Take-Up Pole

Base Ass’y

Ass’y

(TOPVIEW)

A/C Head

Pinch Roller Lever

Pinch Drive Car

Pinch Drive

Lever

Reverse Guide

Main Take-Up Brake Lever

Cassette

Housing Drive Gear

Ass’y

n

SUPPlY

No.

Full erase head

1.

Erase the whole records on the tape in the recording mode.

3.

Tension arm

Detects the tension of tape while running, and brakes

the supply reel disk via the tension band.

7.

Main supply brake lever Brakes the supply reel disk to prevent tape slackening when the unit is stopped in fast forward or rewind mode.

9. Main take-up brake lever

Brakes the take-up reel disk to prevent tape slackening when the unit is stopped in fast forward or rewind mode.

ass’y

Function

ass’y

Take-Up

Lock Lever

@

Loading

Motor

No.

Reverse guide

13.

Pulls out the tape and controls the tape drive train height with the upper and lower guides.

Pinch roller lever

16.

Press-fits tape to the capstan during tape running-The right protrusion switches the clutch of the cassette housing control assembly in “tape eject”, and makes

the mechanism eject tape,

Loading motor

18.

A motive power which drives the mechanism. It

transmits the power to the master cam and cassette housing control assembly .

Function

ass’y

Reel Disk

16

FUNCTION OF MAJOR MECHANICAL PARTS

(BOTTOM VIEW)

Capstan

DD

Motor

o-

3

9

Take-up

Loading Gear

P

Reel Belt

Slow Brake Lever

Master Cam

Cassette Housing Drive Gear

Connect Gear 5

o++

@,

1

o-

@,

Clutch Gear

@

\

10

0

6

Reel Pulley

0

8

Shifter

0

Clutch Connect Arm

No.

Slow brake lever

1.

Gets in contact with the capstan

the master cam in the slow still mode, and brakes it to a

certain degree.

3.

Capstan A motive power which runs the tape. It transmits the power via the reel belt.

4.

Reel belt Transmits the power to run the tape to the reel pulley.

D.D.

motor

Function

D.D.

motor linking to

No.

6.

Reel pulley Transmits the power of the capstan

reel disk via the reel idler.

8.

Shifter Transmits the operation of the master cam to break

and loading gear.

9.

Take-up loading gear Shifts the take-up pole base and guide roller via the

loading relay gear, and applies the tape around the drum assembly, as well as transmits the power to the supply loading gear.

Function

D.D.

motor to the

VT-3428X VT-51 28X

ADJUSTMENT, REPLACEMENT AND ASSEMBLY OF

MECHANICAL UNITS

_

Here we will describe a relatively simple service

work in the field, not referring to the more complicated repairs which would require the use of special equipment and tools (drum assembly

We are sure that the easy-to-handle tools listed

below would be more than handy for periodical maintenance to keep the machine in its original

working condition.

replacement, for example).

TbOLS

NECESSARY FOR ADJUSTING THE MECHANICAL UNITS

The following tools are required for proper service and satisfactory repair.

-

0.

-

Reel Disk Height Adjusting Jig

1

-

Master Plane Jig

2

-

3

A/C Head Tilt Adjusting Jig

-

4

-

Jig Item

Part No. Code

JiGRH0002 BR

JiGMPOOOl BY

I

9DAACH-A323U

I I

BX

Configuration

42

acD

Gauge Head

5

-

6

Cassette Torque Meter

-

Tension Gauge (3009)

7

Tension Gauge (2.0kg)

-

Hex Wrench (0.9mm)

a

Hex Wrench (1.2mm)

Hex Wrench (1.5mm)

-

Alignment Tape (PAL)

9

Alignment Tape (PAL)

-

JiGTH0006

JiGVHT-063 CZ

JiGSG0300

JiGSG2000

JiGHW0009 AE

I

JiGHWOOl2 AE

JiGHWO015 AE

VROCPSV

VROUBZFS

AW

BF

BS

1

I

f!3

Remarks

These Jigs are used for checking and adjusting the reel disk height.

This Jig is used for setting the A/C

head tilt.

These Jigs are used for checking and adjusting the torque of take-up and supply reel disks.

This cassette torque meter is used for checking and adjusting the torque of take-up for measuring tape back tension-

There

are two gauges used

tension measurements, 300 g and

2.0 kg.

These Jigs are used for loosening or

tightening special hexagon type

screws.

These tapes are especially used for electrical fine adjustment.

for the

11

Tension Gauge Adapter

b

/ JiGADP003 / BK 1

18

This Jig is used with the tension gauge. Rotary transformer clearance adjusting jig.

No.

Jig Item

Part No. Code

Configuration

Remarks

Special Bladed Screwdriver

12

Torque Driver

14

Box Driver

15

Reverse Guide Height

17

Adjusting Jig

JiGDRiVERH-4 Ap

JiGTDl200

JiGDRiVER

JiGDRiVER 10-4 AV

JiGDRiVER

JiGRVGH-F18

1

lo-55

O-7

AR

CB

AS

BU

This screwdriver is used for adjusting the guide roller height.

This is used to screw down

made parts: the specified torque is

-

C

/

:

kg-

This Jig is used for height

ment

of the A/C head and X-

position.

This Jig is used for replacement of the SI roller.

’

This Jig is used for height adjust-

ment of the reverse guide.

This Jig is used for height

ment

of the reverse guide.

resin-

5

adjust-

19

W-3428X W-51 28X

MECHANICAL PARTS REQUIRING PERIODICAL INSPECTION

Use

the following table as a guide to maintain the mechanical parts in good operating condition.

500

1000 1500 2000

hrs. hrs. hrs. hrs.

Possible symptom encountered

Remarks

Guide roller

Supply impedance roller

(inner hole and shaft)

Supply impedance roller flange

Retaining guide

Slant pole

Video head (upper/Lower drum

ass’y)

Full-erase head

A/C head

Capstan

Pinch roller

Reel belt

Tension band

Loading Motor

D.D.

ass’y

Motor

ass’y

q q q 0

Cl

q cl 0

cl

cl cl cl

cl cl cl El

q

Lateral noises Head occasionally blocked

cl

cl q cl 0

El

q q

Cl

0 cl 0

cl q

0

Cl

0 Cl 0 Cl

0

Poor S/N ratio, no Poor flatness of the envelope with alignment tape

Poor

0

colour,

Sound too small or distorted

No tape running, uneven

colour

beating

cl q cl 0 No tape running, tape slack

III

No tape running, tape slack, no

0

fast forward/rewind motion

0

Cassette not loaded or unloaded

0

Abnormal rotation or significant vibration requires replacement.

Clean with pure high quality isopropyl alcohol.

Clean tape contact part with the specified cleaning liquid.

Clean tape contact area with the specified cleaning

liquid.

colour

Clean rubber and rubber contact area with the specified cleaning liquid.

.

Reel idler

Reel

Clutch gear

Main supply/take-up brake levers

AHC

NOTE:

ass’y

pully ass’y

ass’y

(Automatic Head Cleaner)

0:

Part replacement.

q

A

0 0

No tape running

0

00

0

0 Tape slack

Cl :Cleaning (For cleaning, use a lint-free cloth dampened with pure isopropyl alcohol).

A:

Oil refilling (The indicated point should be lubricated with high quality spindle oil every

hrs).

If the reading is out of the specified value, clean or replace the part.

Replace the roller of the cleaner when it wears down. Just change the assembly for new one.

AHC

roller

1000

,

20

VTg3428X VT-51 28X

REMOVAL AND REASSEMBLY OF

CASSETTE HOUSING CONTROL ASSEMBLY

l

Removal

1.

Set the cassette ejected condition in the cassette

eject mode.

2.

Unplug the recorder from the main source.

3.

Follow the procedures below in the specified

order. a) Remove the cassette housing installation

screws 0 and

b)

Slide and pull out the cassette housing control

assembly upward.

\

.

a.

m

\

Cassette control drive gear

2.

Follow the procedures for removal in the reverse

order.

Notes:

0

In using a magnet screw driver, be sure to keep it

away from the A/C head, FE (Full Erase) head, or the drum.

Q

In removal and reassembly, take care not to hit

the cassette housing control assembly or tools

against the guide pin, drum, or the like thereabout.

0

Load the cassette once onto the cassette housing

control assembly after reassembly.

I

Drive angle of cassette control

l-

Figure

l-2.

Figure l-l.

l

Reassembly

1.

Before installation of the cassette housing

control assembly, make a short-circuit between

TP8804 and TP8805, both located at the center

on your side on the VCR

resistor. Plug in the power cord. The cassette control drive gear starts and stops just when a tally mark appears in the mechanism chassis window. Align this tally mark with the cassette control drive angle’s mark, as shown in Fig. to position the cassette control on the mechanism chassis.

PWB,

with a 22 ohm

l-2,

TO RUN A TAPE WITHOUT THE CASSETTE

HOUSING CONTROL ASSEMBLY

1.

Be sure to make a short-circuit between TP8804

and

TP8805,

side on the VCR before turning on the power.

2.

Plug in the power cord.

3.

Turn on the power switch.

4.

Open the lid of a cassette tape by hand.

5.

Hold the lid with two pieces of vinyl tape.

6.

Set the cassette tape in the mechanism chassis.

7.

Stabilize the cassette tape with a weight

to prevent floating.

8.

Perform running test.

Weight to prevent

Note:

The weight should not be more than

both located at the center on your

PWB,

with a 22 ohm resistor,

(500 g)

chanism chassis

Figure

1-3.

500 g.

21

1

W-3428X VT-51 28X

REPLACEMENT AND HEIGHT CHECKING

AND ADJUSTMENT OF REEL DISKS

l

Removal (Supply and Take-up reel disks)

1.

Remove the cassette housing control assembly.

2.

Pull the tension band out of thetension arm.

3.

Remove the supply main brake and the take-up

main brake.

4.

Open the hook at the top of the reel disk, and

remove the reel disk.

Takeup

Tension Arm Ass’y

Supply reel disk

main brake

Take-up reel disk

Notes:

@Take enough care not to deform the tension

band during installation of the supply reel disk.

@

Be careful not to damage the supply main brake.

l

Reassembly (Take-up reel disk)

1.

Clean the reel disk shaft and apply oil to it.

2.

Install a new take-up reel disk onto the shaft.

3.

Check the reel disk height and reassemble the

take-up main brake. Note: Take care not to damage the take-up main brake.

After reassembly, check the video search rewind

back tension (see page

25)‘

and check the brake

torque (see page 28).

Height checking and adjustment Note :

Place the master plane onto the mechanism unit, taking care not to hit the drum (see Figure

l-6).

Figure

l-4.

Note: When the tension band is pressed in the direction of the arrow for removal, the catch is hard to be deformed.

Figure

l-5.

l

Reassembly (Supply reel disk)

1.

Clean the reel disk shaft and apply oil to it.

2.

Install a new supply reel disk onto the shaft.

3.

Replace the tension band around the supply reel

disk, and insert it to the hole of the tension arm.

4 Check the reel disk height and reassemble the

supply main brake.

SUI

Set the master plane releasing the reverse guide by a finger.

Figure

l-6.

22

l

Check that the reel disk is lower than part A but higher than

part

If the height is not correct,

B.

readjust the reel disk height by changing the

poly-slider washer under the reel disk.

Note: Whenever replacing the reel disk, perform the height checking and adjustment.

Adjustment

1.

If the take-up torque is outside the range, clean

the capstan

pulley with cleaning liquid, then recheck the

torque.

2.

If the take-up torque is still out of range, replace

the reel belt.

D.D.

motor pulley, reel belt and reel

Notes:

Master plane

10 2 0.2mml

.

1

Reel disk

Reel disk height

adjusting jig

J

1

Mechanism chassis

1.

Hold down the torque gauge so that it may not

fly off.

2.

When checking the take-up torque, do not keep

the reel disk locked for a longer time.

CHECKING AND ADJUSTMENT OF TAKE-UP

Reel disk

Figure

I

l-7.

CHECKING AND ADJUSTMENT OF TAKE-UP TORQUE IN FAST FORWARD MODE

0

Remove the cassette housing control assembly.

0

Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

turn on the power.

0

Setting

1.

Set a torque gauge to zero on the scale. Place it on the take-up reel disk.

2.

Press the FF button to set the mechanism to the fast forward mode.

0

Checking

1.

Turn the torque gauge slowly (one rotation every 2 to 3 seconds) by hand in the take-up

i I

direction.

2.

Check to see if the take-up torque is higher than

69 mN-m (700 gfcm).

TP8804

and

TORQUE IN REWIND MODE

0

Remove

0

Make a short-circuit between

TP8805,

on the VCR turn on the power.

0

Setting

1.

Set a torque gauge to zero on the scale. Place it

on the supply. reel disk.

2.

Press the REW button to set the mechanism to

the rewind mode.

0

Checking

1,

Turn the torque gauge slowly (one rotation

every 2 to 3 seconds) by hand in the take-up

direction.

2

.

Check to see if the take-up torque is higher than

69 mN*m (700 gf-cm).

the

cassette housing control assembly.

TP8804

and

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

f

I

69mN.m (70Ogf.cm)

i

.i

69mN.m (700gf.cm)

or more

Figure

l-8.

guage

1

its maximum value.

(Red mark)

3

Take-up direction

is held at

Figure

The guage is held at its maximum value.

l-9.

23

VT-3428X

VT-5128X

l

Adjustment

1.

If the

take-u1

the capstan

torque is outside the range, clean

Q

D.D.

motor pulley, reel belt and reel pulley with-cleaning liquid, then recheck the torque.

2.

If the take-up torque is still out of range, replace

the reel belt.

Notes:

1.

Hold down the torque gauge so that it may not

fly off.

2.

When checking the take-up torque, do not keep

the reel disk locked for a longer time.

CHECKING AND ADJUSTMENT OF TAKE-UP TORQUE IN PLAYBACK MODE

Remove the cassette housing control assembly.

1.

2.

Make a short-circuit between

TP8805, both located at the center on your side

on the VCR

PWB,

with a 22 ohm resistor. Now plug in the power cord and turn on the power. Open the lid of the cassette torque meter, and

3.

hold it with two pieces of vinyl tapes. Load the cassette torque meter into the unit.

4.

Put the weight (5009) on the cassette torque

5.

meter.

6.

Press the

REC

button to put the unit in

mode.

TP8804

and

REC

CHECKING AND ADJUSTMENT OF TAKE-UP TORQUE IN VIDEO SEARCH REVERSE

MODE

l

Remove the cassette housing control assembly.

l Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

turn on the power.

l

Setting

1.

Push the PLAY button to place the

playback mode.

2.

Push the

video search reverse mode.

l

Checking

1.

Place the torque gauge on the supply reel disk,

and turn it counterclockwise very slowly (one

rotation every 1 to

torque is within the set value

Tii

gfcm)

Torque

REW

button to place the

2 seconds) and

gaug

TP8804

ass’y

and

in the

check that the

14.5 Ti mN*m (148

Set value EP

0

Checking

1.

Check that the torque is in the range of 8.8

3.8mNmm (90 +

2.

The torque fluctuates due to the rotational deviation of the reel pulley

8.8 + 3.8mN.m (90 f 39gf-cm)

Figure

l-1

0.

39gfcm).

ass’y.

Use the center

of the fluctuation as the value.

3.

Place the

ass’y

in the SP record mode, and check

that the take-up torque is within the range.

0

Adjustment

If

the take-up torque in the playback mode is

outside the range, replace the reel pulley

ass’y.

Note: Stabilize the cassette torque meter to prevent floating.

Supply reel disk

Figure l-l

1.

Note:

Set the torque gauge securely on the supply reel

disk. If it is not secure, the measurement will be

incorrect.

+

l

Adjustment

If the take-up torque

is outside the range, replace the reel pulley

in video search reverse mode

ass’y.

Note:

The torque fluctuates due to the rotational deviation of the reel pulley

the fluctuation at the value.

ass’y.

Use the center of

24

CHECKING THE FAST FORWARD BACK TENSION

l

Remove the cassette housing control assembly.

l Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

turn on the power.

l

Checking

I. Push the FF button to place the

fast forward mode.

2.

Place the torque gauge on the supply reel

disk, and turn it clockwise very slowly (one rotation every 2 to 3 seconds) and check that

the torque is I .5 *

Torque gauge

Supply reel disk

0.9mN.m

Figure

l-1

2.

Note:

0

Set the torque gauge securely on the supply reel

disk. If the torque gauge is not securely set on the reel disk, measurement will be incorrect.

QMeasure the torque with the torque gauge’s

weight exerted on the reel disk.

(I 5 +

TP8804

ass’y

9gfcm).

and

in the

/

KZ::

2.

Place the torque gauge on the take-up reel

disk, and turn it counterclockwise very slowly (one rotation every 2 to 3 seconds) and check that the torque is I .3 2

gfcm).

Note: @Set the torque gauge securely on the take-up

reel disk. If it is not secure, the measurement will be incorrect.

QMeasure the torque with the torque gauge’s

weight exerted on the reel disk.

0.8mNem

(I 3 + 8

CHECKING THE VIDEO SEARCH REVERSE

BACK TENSION

Remove the cassette housing control assembly.

Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

turn on the power. Checking

Push the PLAY button to place the

playback mode.

Push the rewind button to place the

video search reverse mode.

Place the torque gauge on the take-up reel disk,

and turn it counterclockwise very slowly (one

rotation every 2 to 3 seconds) and check that the

torque is within the set value 4 f

(41 f 17gfcm).

-

Torque gauge

TP8804

\-

,

‘f’

and

ass’y

in the

ass’y

in the

1.7mNam

.

CHECKING THE REWIND BACK TENSION

l

Remove the cassette housing control assembly.

l Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

turn on the power.

l

Checking

I. Push the REW

rewind mode.

buton

to place the

Torque gauge

Take-up reel disk

Figure

l-l

3.

TP8804

ki

,

/

ass’y

and

in the

Take-up reel disk

Figure-l-14.

Note:

0

Set the t

reel disk. If it is not secure, the measurement will be incorrect.

QMeasure the torque with the torque gauge’s

weight not exerted on the reel disk.

orque

gauge securely on the take-up

CHECKING THE PINCH ROLLER PRESSURE

l

Remove the cassette housing control assembly.

l Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

turn on the power.

l

Checking

Push the PLAY button to place the playback mode.

TP8804

ass’y

and

in the

25

m-3428X VT-51 28X

Tension gauge

900-l

,200 g

2.

Visually check to see if the left end of the tension

pole is in alignment with the line the center line of the SI roller. Readjust as

required in the following steps.

0.2mm

left of

Pinch rolle

Capstan shaft

1.

Detach the pinch roller from the capstan shaft.

2.

Set the tension gauge by hooking the tension

gauge adapter onto the pinch roller shaft.

3.

Gradually release the pressure to allow the pinch

roller to touch the capstan shaft. When the pinch roller just touches the capstan shaft, read the indication on the gauge.

4.

Check that the reading of the tension gauge is in

the range of 900 to

Tension gauge adapter

Figure

l-1 5.

1200 g.

CHECKING AND ADJUSTMENT OF TENSION

POLE POSITION

l

Remove the cassette housing control assembly.

Tension/pole

I

0.2mm

I

Center line

Make the adjustonent with the beginning of a

E-180

tape.

0

If the end is at the left from the center line:

+fw

-+

Figure

l-1 7.

l Make a short-circuit between

TP8805,

on the VCR

turn on the power.

l

Setting

1.

Open the lid of cassette tape (E-180), and hold it

with two pieces of vinyl tapes.

2.

Load the cassette tape into the unit.

3.

Put the weight

4.

Make the adjustment with the beginning of a

E-l 80 tape.

l

Checking

1.

Set a cassette tape, press the

the tape loaded. Now check the tension pole position.

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

(500g)

on the cassette tape.

Figure

l-16.

TP8804

REC

button and get

and

26

Figure

l-18.

1.

Remove the cassette and press the

make an empty loading. Put a bladed screwdriver into the tension band positioning cam and turn it clockwise.

2.

Place the cassette in position and check the

tension pole position.

@

If the end is at the right from the dotted line:

I

@

4

Figure l-l

1.

Remove the cassette and press the

make an empty loading. Put a bladed screwdriver into the tension band positioning cam to turn it counterclockwise.

2.

Place the cassette in position and check the

tension pole position.

.

i

I

0

1

I

0.2mm

I

L-1

9.

REC

button to

REC

button to

Note:

@The tension band positioning cam cannot be

adjusted with a cassette in place because the cam

will be located below the cassette. Repeat a

series of steps; empty loading, adjustment, cassette placement and position checking.

aTurn

@Adjustable range of the tension pole positioning

the positioning cam clockwise to move the

tension pole to the right (in the black-arrow

direction). Turn it counterclockwise to move the tension pole to the left (in the white-arrow direction).

Figure

l-20.

cam.

Tension arm shaft

\

arm

VT-3428X VT-51 28X

w

Figure

l-22.

l

Checking

1.

Push the

REC

button to place the unit in the

record mode.

2.

Check that the back tension indicated by the

gauge is within the set range 31 to 38 g-cm.

Notes:

1.

Make sure that the video cassette tape is over

the retaining guide.

2.

Make sure that the tape is not slack nor damaged at either end.

0

Adjustment

1.

If the reading of the cassette torque meter is less than specified, move the tension spring hook

toward A.

2.

If the reading of the cassette torque meter is more than specified, move the tension spring hook toward

B.

meter

Tension pole adjusting cam

Figure

l-21.

Adjust the tension pole positioning cam so that the arrow mark on the cam be within

90”

left and right

from the tension arm shaft’s center.

CHECKING AND ADJUSTMENT OF RECORD / PLAYBACK BACK TENSION

l

Remove the cassette housing control assembly.

l Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. NOW

turn on the power.

l

Setting

1.

Open the lid of the cassette torque meter, and

hold it with two pieces of vinyl tapes.

2.

Load the cassette torque meter into the unit.

3.

Put the weight (5009) on the cassette torque

meter.

TP8804

and

Figure

ping

l-23.

27

m-3428X VT-5128X

I

1

CHECKING THE BRAKE TORQUE

l

Checking the brake torque at the supply side

,

Supply reel disk

5-l

5mN.m (SO-1

lo-50mN.m (102-SlOgf-cm)

Figure

l

Remove the cassette housing control assembly.

SOgf-cm)

l-24.

l

Checki4the brake torque at the take-up

CCW: lo-50mN.m (102-510gfxm) CW:

5-l

5mN.m (SO-1

Figure

l

Remove the cassette housing control assembly.

SOgf-cm)

l-25.

side

l Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

TP8804

and

turn on the power.

0

Setting

1.

Set a torque

on the supply reel disk.

2.

Switch from the FF mode to the STOP mode.

3.

Disconnect the AC power plug.

l

Checking

1.

Slowly rotate the torque gauge in the clockwise

(CW)

direction and counterclockwise direction of the supply brake so that the reel disk and the indicator of the torque gauge rotate at an equal rate. Check that the values are within the range of CW direction =

(102-510gfcm), CCW (50450gfcm),

CW

direction is at least twice as high as that in

the

CCW

gauge to zero on the scale. Place it

IO-50mN.m

direction =

and that the brake torque in the

direction.

545mN*m

(CCW)

l Make a short-circuit between

TP8805,

on the VCR

both located at the center on your side

PWB,

with a 22 ohm resistor. Now

TP8804

and

turn on the power.

0

Setting

1.

Set a torque gauge to zero on the scale. Place it

on the take-up reel disk.

2.

Switch from the FF mode to the STOP mode.

3.

Disconnect the AC power plug.

l

Checking

1.

Slowly rotate the torque gauge in the clockwise

(CW)

direction and counterclockwise direction of the take-up brake so that the reel disk and the indicator of the torque gauge

rotate at an equal rate. Check that the values

are within the range of

IO-50mN.m

545mN*m (50450gfcm),

torque in the

high as that in the

l

Adjustment of the brake torque at the supply

(102~510gfcm), CW

CCW

direction is at least twice as

CVV

direction.

CCW

direction=

direction =

and that the brake

(CCW)

side and the take-up side

1.

If the supply or take-up brake torque is outside

the range, clean the supply or take-up reel disk

break lever pad, then recheck the torque.

2.

If the supply or take-up brake torque is still

outside the range, replace the main brake or the main brake spring.

Note:

When the main brake is replaced, perform the

height checking and adjustment of reel disks (see page

22),

and the brake torque checking.

ass’y

28

VT-3428X VT-51 28X

REPLACEMENT OF A/C (Audio/Control) HEAD

1.

Remove the cassette housing control assembly.

2.

Place the unit in the unloading mode, and

unplug the power cord.

l

Removal

1.

Loosen the tilt adjusting screw

2.

Remove the azimuth adjusting screw

3.

Remove the AK head screw

4.

Unsolder the A/C head PWB soldered to the A/C

0. a.

0.

Figure

head assembly.

Notes:

1.

After replacement, be sure to perform the

adjustment of the tape drive train (see page

33).

Under any circumstances, avoid touching the head. Clean the head, if touched with your

finger, with alcohol.

2.

Take care that the azimuth spring does not fly

1

off when removing the A/C head screw.

l

Adjustment

[A/C

head tilt angle]

1.

Set the mechanism to the loading mode.

2.

Place the A/C head tilt adjusting Jig

3.

Slowly turn the tilt adjusting screw Q with a

screw driver until there is no gap between the Jig and the AK head.

A piece of white paper

_

(fqr

visuality of a gap)

adjusting nut

l-28.

0.

A/C head

Pay attention to

l

Replacement

1.

Solder the removed A/C head

AK

head assembly.

2.

The A/C head assembly is attached so that the

-

Figure

l-26.

PWB

onto a new

PCB

A/C head arm and A/C head plate are roughly parallel to each other.

PCB

A/C head

New

A/C head tilt adjusting jig

AK

head arm

Tilt adjusting screw

Screw driver

A/C

J

Figure

head

(W

l-29.

Never

touch the

Figure

\

A/C head plate

l-27.

29

VT-3428X VT-51 28X

[A/C head height rough adjustment]

l

Setting

1 k

Box driver

Figure

l-30.

HEIGHT ADJUSTMENT OF REVERSE GUIDE

[Height adjustment of reverse guide]

Reverse guide height

adjusti?g jig

guide

Reverse guide height

adjusting jig

Go-end is mm. Not go-end is

13.38

13.52

mm

4-f

(a)

Figure

l-33.

1.

Remove open lever (Figure In the tape load mode, make adjustment at the

2.

13.38mm

adjusting nut by Actually load the unit with a tape, put it in the

3.

play mode, and make sure the tape is free from

wrinkles near the reverse guide.

4.

Use a commercially available box driver to turn

the height adjusting nut.

side first and then rotate the height

l/6

turn counterclockwise.

l-34.

W

(a))

:hassis

Figure

l-31.

aRoughly

turning the A/C head adjusting hexagon nut with the specialized box driver until the tape is in

the position shown below. @Set the cassette tape to the mechanism chassis.

@ Press the PLAY button to the put the unit in the

playback

0

Adjustment

Adjust the nut visually so that the control head is visible

adjust the height of the A/C head by

mode.

Figure

l-32.

0.3

to

0.5mm

below the bottom of the tape.

Box driver

Q

Height adjusting nut

30

Figure

l-34.

m-3428X V-T-5128X

ADJUSTMENT OF TAPE DRIVE TRAIN

1.

Remove the cassette housing control assembly. Make a short-circuit between

2.

t

TP8805, both located at the center on your side

on the VCR turn on the power.

Check and adjust the position of the tension

3.

pole. (See page 26.)

4.

Check and adjust the video search rewind back

tension. (See page

5.

Set the tilt angle of the A/C head. (See page

Rough adjustment of tape drive train.

6.

a) Connect the oscilloscope to the test point for

PB CHROMA

the synchronism of the oscilloscope to EXT. The PB the head switching pulse

b)

Loosen the setscrew at the lower part of the

guide roller, and adjust it with an adjusting

screw driver

roller turns smoothly. (Do not overloosen the

setscrew, which causes insecurity of the guide

roller.) (See Figure

c)

Set the alignment tape (monoscope pattern)

on the reel disk, and place the unit in the

playback mode. (Place a prevent floating of the cassette tape.)

Guide roller

PWB,

with a 22 ohm resister. Now

25.)

envelope output (TP2203). Set

CHROMA

500

signal is to be triggered by

(TP2204).

(JiGDRIVERH-4)

l-35.)

g weight on the cassette tape to

TP8804

so that the guide

and

29.)

z

Wrinkles at upper flange

(a)

Wrinkles at lower flange Counterclockwise

0.4

Figure

l-37.

Notes:

1.

Place the tracking control in the center position,

and adjust the X-position adjusting nut so that the PB easier rough adjustment of the tape drive train.

2.

In the rough adjustment, pay particular

attention to the outlet side.

CHROMA

envelop becomes maximum for

Clockwise

Figure

l-35.

d)

In the X value adjustment mode (see the

Electrical Adjustment), change the envelope

waveform from MAX to

by pushing the ( + ) or check a flat response is obtained on the

waveform.

e)

If a flat response cannot be obtained, roughly

adjust the guide rollers on the supply side and

take-up side using an adjusting screw driver

until a flat response can be obtained.

f)

Turn the A/C head tilt adjusting screw with a

screwdriver to prevent the tape from wrinkling at the upper and lower flanges of the fixed guide.

1)

Wrinkles at the upper flange : Turn the

above adjusting screw clockwise, as shown in Figure

2)

Wrinkles at the lower flange : Turn the

above adjusting screw counterclockwise, as

shown in Figure

1-37

(a).

1-37 (b).

Figure

l-36.

MIN,

and

MIN

to MAX

(-)

tracking button, and

Loosen the setscrew

31

Figure

8

l-38.

Figure

X-position adjusting nut

l-39.

m-3428X W-5128X

PB CHROMA

-.;i&;

Head switching pulse

7.

Adjustment of A/C head height and azimuth

Connect an oscilloscope to the audio output

a)

envelope

Figure

(TP201)

(TP202)

l-40.

terminal.

Use the alignment tape and play back its

b)

audio 6

kHz

signal (monoscope pattern for video signal). Adjust the azimuth adjusting screw to obtain the maximum audio output on an oscilloscope. (See Figure

Use the alignment tape and play back its

d

audio 1

kHz

signal (colour bar for video signal)

1-41.)

and slowly rotate the A/C head height adjusting nut with the special box driver to obtain the maximum audio output.

Perform the adjustment in b) again.

d)

After this adjustment, apply

e)

glyptal

screws and nuts to fix them.

to the

Box driver Azimuth adjusting screw

Figure

l-41.

.

Adjustment of tape (VROUBZFS) drive train and

8

Figure

A/C head height

adjusting screw

nut

l-42.

X-Position.

Connect the oscilloscope to the test points

a)

(TP2203)

for PB

CHROMA

envelope output. Set the synchronism of the oscilloscope to EXT. The PB the head switching pulse

Play back the tape drive train alignment tape.

b)

Push the

d

CHROMA

(+)

or

signal is to be triggered by

(TP2204).

(-)

button to change the envelope waveform from MAX to MIN, and

MIN

to MAX. Adjust the guide roller’s height on the supply and take-up sides with an adjusting screw driver, to obtain an envelop waveform that is as flat as possible.

If the tape is above or below the helical lead,

d)

the PB shown in Figure Adjust for maximum flatness of the envelope

d

CHROMA

waveform will take the shape

l-43.

as the step 6, e) in page 31.

~?I~qyTyTpq

.

Adjustment

When the tape is above the helical lead. When the tape is below the helical lead.

Supply side

p-,

Supply side guide roller rotated in clockwise direction (lowers guide roller) to flatten envelope.

Take-up side

Take-up side guide roller rotated in

clockwise direction

(lowers guide roller) to

flatten envelope.

Figure

-;y$-Ja

l-43.

Supply side

Supply side guide roller rotated in counterclockwise direction (raises guide roller) to make the

tape float above the

helical lead. The supply side guide roller is then rotated in the clockwise direction to flatten the envelope.

Take-up side

Take-up side guide roller rotated in counterclockwise direction (raises guide roller) to make the

tape float above the

helical lead. The take-up side guide

roller is then rotated in the clockwise direction to flatten the

envelope.

32

f)

Push the

(+)

or (-) tracking button to check that a flat response is obtained on the envelope waveform.

g)Secure the guide roller by tightening the

guide roller setscrew in the unloading mode.

h)

Play back the tape drive train alignment tape

to check that the envelope waveform does

not change.

9.

Adjustment of A/C head X-position.

a) In the X value adjustment mode (see the

Electrical Adjustment), make a short circuit between

the on your side on the VCR

TP8804

and

TP8805,

both located at

PWB,

with a

ohm resistor to center the tracking.

b)

Rotate the X-position adjusting nut with an

adjusting box driver, and adjust the A/C head

position for maximum head switching pulse low side envelope.

c)

Adjust the playback switching point.

d)

Check the flatness of the envelope waveform

and sound by playing back a recorded tape.

X-position adjusting nut

l-

2mm

Main chassis

Figure

l-44.

REPLACEMENT OF THE CAPSTAN D.D. (DIRECT DRIVE) MOTOR

0

Remove the cassette housing control assembly.

0

Removal (Follow the order of indicated numbers.)

1.

Disconnect from the board-to-board connector on the VCR PWB.

2.

Remove the reel belt

3.

Remove the screws

0.

@.

22

l

Reassembly

1.

Mount the capstan motor on the mechanism

chassis making sure not to allow the capstan shaft to hit the mechanism chassis, and attach it with the three screws.

2.

Attach the reel belt. Reconnect to the board-to

board connector on the VCR

PWB.

Notes :

1.

After installing the capstan

to rotate the capstan

D.D.

motor, be sure

D.D.

motor and check the

movement.

2.

Check the servo circuit.

REPLACEMENT OF D.D. MOTOR

1.

Put the unit in the cassette eject position.

2.

Unplug the power cord.

l

Removal (Reverse the order in reassembly.)

1.

Disconnect the

2.

Unscrew the stator assembly fixing screws

3.

Take out the stator assembly

4.

Unscrew the rotor assembly fixing screws

5.

Take out the rotor assembly

Notes:

1.

In removing the stator assembly, part of the drum earth spring pops out of the collar.

Be careful not to lose it.

2.

Secure the rotor assembly so that the installation positioning holes in the rotor assembly and upper drum assembly match. (Match the upper drum’s notch with the rotor’s

hole.)

3.

Be careful not to damage the upper drum or the video head.

4.

Be sure that the hall device and the assembly are not damaged by the rotor assembly or other parts.

5.

After installation, adjust the playback switching point.

2

CL

FFC

cable

0. @.

@.

pre-load

stator

Figure

l-45.

motor

Figure

l-46.

ASSEMBLE THE MECHANISM’S PARTS

REQUIRING THE PHASE MATCHING IN THE STEPS BELOW.

I

, Assembling the pinch roller assembly and the

pinch drive cam (on the front of the mechanism

chassis).

2.

Mounting the shifter (on the back of the

mechanism chassis).

3.

Mounting the master cam (on the back of the

mechanism chassis).

4.

Mounting the connection gear, slow brake and

loading motor assemblies (on the back of the mechanism chassis).

1.

Assembling the pinch roller assembly

and the pinch drive cam (on the front of the mechanism chassis).

Place the following parts in position in numerical order.

(1)

Pinch drive cam

(2)

Pinch roller and pinch double-action lever

(3)

Open lever

0

Insert Pinch Drive Cam.

Fit the point of the pinch drive cam to the fourth tooth of the pinch drive insert the pinch drive cam.

Fit the pinch drive cam’s hollow part and the pinch drive lever’s hollow part to chassis position.

Phase Matching Point

1

lever,and

\

I7

Pinch Drive Cam

Figure

l-47.

34

Figure

148-l.

Q

Insert Pinch Roller/Pinch Double Action Lever

Ass’

y.

Pinch Roller Pinch Double

Phase-Matting Point

@

Action Lever

Ass’y ,

0

Insert Open Lever.

VT-3428X VT-5128X

Figure l-48-2.

Figure

l-48-3.

35

VT-3428X VT-51 28X

2.

Mounting the shifter (on the back of

the mechanism chassis)

Capstan

D.D.

Motor

0

P

Reel Pulley

0

rl

(Bottom Side of mechanism chassis)

Figure

l-49.

Insert

Point o

Cut Washer

,

LX-WZ1041GEOO

1.

Make sure that the loading gear is at the point 0 as shown below.

2.

Place the shifter in position, keeping in mind

the CD insertion points and the 6) relief points.

3.

For the phase matching at the insertion point

0,

see the point 0 as shown below.

-

Drum

I

4.

Finally fix the shifter with two washers located

on insert points 0 and

Phase-Matching Point

0

6).

Insert Point

A -

@

L!!

Insert Point

@I

,

I

Point

Eh

i’

\

Y

czb----

Figure

36

l-50.

1

iE~ft::

3.

Mounting the master cam (on

the back

of the mechanism chassis).

(1)

Make sure beforehand that the shifter is at

the point as shown below.

(2)

Place the master cam in the position as shown

below.

E-ring (XRESJ40-06000)

?

Master Cam

Note: See the figure below for the phase matching between the master cam and the cassette control drive gear.

Finally fix the master cam with

(3)

E-ring.

I

\

Master Cam

ette

Housing

Drive

Figure

l-51.

4.

Mounting the connection gear, slow

brake and loading motor assemblies

(on the back of the mechanism chassis).

(1)

Assemble the connect gear.

(2)

Assemble the slow brake.

(3)

Assemble the loading motor unit.

Note: Let the slow brake leg out of the front of the mechanism chassis. Catch the spring to the take- up fixing guide that is at the left of the A/C head.

@

Slow

Brake

,\.\

A%

0

Figure

Note:

Before setting up the loading motor, make sure the phase is matched. To do so, turn the connection gear clockwise and check to see if the loading is complete and if the pinch roller comes into contact.

Kfing Motor

l-52.

When these actions are made smoothly, return the

mechanism to the state as shown above. Finally mount the loading motor unit.

38

REPLACEMENT OF LOADING MOTOR

l

Removal

Remove 2 screws.

Figure.l-54.

Q

Adjust the worm gear’s thrust gap to 0.05 to

0.3

mm.

Use the specific washers for an appropriate

thichkness.

VT-3428X VT-51 28X

Figure

l-53.

l

Replacement

0

Take out the old loading motor. Place a

replacement loading motor as shown above (Figure

l-53.).

1

13.0 +

O.lmm

1

To press the motor in,

receive it by portion A.

Figure.l-55.

Press-fit the loading motor pulley with a force of less than

13.0 +

98N

(10 kgf). Be sure that the pulley is

0.05 mm away from the motor.

39

VT-3428X VT-51 28X

ASSEMBLY OF CASSETTE HOUSING

0

Drive Gear R and Drive Angle

Ass’y

MSPRT0381 AJFJ

Apply grease

Phase Matching Point

l Fix the drive angle ass’y to the

drive gear

Ras

shown in the figure.

Drive gear

Figure.l-56.

+-

R

Drive angle

ass’y

40

@

Synchro

Gear, Drive Gear Land Drive Gear

R

Insert the jig shaft.

Stamp mechanism code

\

LANGF9570AJFW

\

/

Top

surface should be free from scraches or soil.

Phase Matching Point

Figure

I-58.

Note:

Do not over-turn both of the drive gears when the

phase has been matched. These gears are partially

toothless and might come out of mesh with the

synchro gear.

In such a case, the phase needs

rematching.

Align the drive gear’s round hole with the gear’s triangular

(A)

symbol. Do this alignment for

both the drive gears.

jig shaft.

synchro

41

i/T-3428X VT-51 28X

ADJUSTMENT OF THE

. VCR ELECTRICAL CIRCUITRY

Notes:

l

Before the adjustment: Electrical adjustments discussed here are often required after replacement of electronic components and mechanical parts such as video heads. Check that the mechanism and all electric components are in good working condition prior to the adjustments, otherwise adjustments can not be completed.

l

Instruments required:

@Audio

@ @AC

@

@I

l

Adjustment of the VCR should be done in the TV/VCR

signal generator

Dual-trace oscilloscope

milli-voltmeter Frequency counter Blank video cassette tape

@Screwdriver for adjustment

@Colour @DC voltmeter

@Alignment tape

combinated

bar generator

(VROCPSV)

style.

n

SERVO CIRCUIT

ADJUSTMENT

Adjustment of head switching point

Measuring instrument

Mode Cassette Test point

Control R7701

Specification

I.

Put the set in the SERVICE mode by turning the power on with the STAND BY/POWER button while the CH A button on the front panel is being pressed down more than 3 seconds.

2.

Play the alignment tape

the

PROG

the tracking to center. “TEST” is displayed on the screen, it means tracking is in center in the

playback mode. (See Note below.)

3.

Connect a dual

points (Trigger the oscilloscope with the head

switching pulse on

4.

Adjust head switching pulse is the vertical sync as shown in Figure

TP2208

R7701

Dual-trace oscilloscope

Playback

Alignment tape

TP2208 TP2204 (Trigger) to

adjustment control

6.5 2 0.5

button on the remote control to set

so that the leading edge of the

(Video out) to CH 1

head switching point

H (lines)

trace’oscilloscope

(Video out) and

TP2204.)

(VROCPSV)

CH2

(VROCPSV)

6.5H

(lines) ahead of

and press

to the test

2-1.

TP2204.

CH-1: 1

V/div 5Opseddiv

CH-2:2V/div 50,useddiv

6.5

2

0.5H

(lines)

CH-2

HEAD .

SWITCHING

PULSE

Note: To make this adjustment, disable the AUTO TRACKING function.

The AUTO’TRACKING function is disabled in the following cases. (In the playback mode only.)

@When the

tape is played back in the SERVICE mode. (The

display “TEST” appears on the TV screen.

@When the tape is played back, after the cassette

housing control cord is plugged in with making

TP8805 (NON-CAS

(Mechanism operating mode, in this case the SERVICE mode is not needed.

i(

-

Figure

2-l.

PROG

button is pressed after the

ass’y

is removed and the AC

JUMPER) short

-i

TP8804

.

V-sync.

and

circ.uited.

42

n

Test points layout of VCR Main Unit.

9 x5501

0

9

0

X55D.z

a

r---7

.____A

,c2*02

5 “REEL

SENSMl

DBBO3

Adjustment of PAL System LP still picture

vertical jitter

Measuring instrument

Mode

Cassette

Test point Adjusting point[ CH Specification

1.

Play back the LP self-recorded tape in the PAL

System

2.

Using the CH

remote control , make adjustment so that the

vertical jitter.becomes minimum.

3.

Now press the STOP button to stop the tape.

still

Monitor TV

I

1

LP record/Still picture playback

PAL self-recording tape

I

Monitor TV screen

I

Aw (TR e/e)

1

No Vertical jitter.

mode.

Am (TR e/e)

buttons.

buttons on the

Figure

1

I I I

I

2-2.

Adjustment of

NTSC

System EP still

picture vertical jitter

Measuring instrument

Mode Cassette Test point

Adjusting point 1 CH

Specification

1.

Play back the EP recorded tape in the

System still mode.

2.

Using the CH

remote control , make adjustment so that jitter becomes minimum.

3.

Now press the STOP button to stop the tape.

Note :

Datas

of the vertical jitter adjustments are memorized to the

PWB when the still mode is stopped.

Monitor TV

Still picture playback

I

NTSC EP

I

Monitor screen

I

No Vertical jitter.

I

Am (TR e/e)

recording tape

Aw (TR B/G)

buttons on the

E2P-ROM IC

on the TV main

buttons.

I I

I

NTSC

43

m

AUDIO CIRCUIT

Checking of audio playback level

r

Measuring instrument

Mode

Input signal

Test point

Specification

-

AC

milli-voltmeter

Osci

I I

oscope

Playback

Alignment

(1 kHz

Audio Out (pin

(11)

-

9 2

tape.(VROCPSV)

level adjusting signal.)

of El connector)

2dBs (0.6~

or

1

.OVp-p)

L

1.

Playback the Alignment tape.

level adjusting signal)

2.

Connect an AC milli-voltmeter to the Audio

Out (pin

3.

Make sure that the output level is - 9 +

(11)

of El connector).

(VROCPSV

1

2dBs.

kHz

1.

Connect an AC milli-voltmeter to test points

TP6601(

(Use

2.

Set the unit in recording mode.

3.

Adjust R6623 so that the signal level is

2.6mVrms.

+ ) and

TP6602

TP6602( - )-

for ground lead.)

Checking of erase voltage and oscillation frequency

Measuring instrument

Mode

Test point

Control Specification

Oscilloscope

Record

I

Full erase head

I

T660

1

I

70 + 5kHz, 4OVp-p

1

or greater

I I I

I

Checking of audio record level

AC

Measuring instrument

Mode Input signal

Test point

Specification

1.

Connect an AC milli-voltmeter to the Audio

Out (pin

2.

Feed the audio signal shown in table to the

AUDIO IN jack and put the unit A/V input

mode.

3.

Make the self-recording and playback the

recorded portion of the tape.

4.

Make sure that the Audio Out level is as

specified. If it is out of specified value, verify the bias current (Adjustment of audio bias

current below).

(11)

of El connector).

milli-voltmeter

Osci

I I

oscope

Record/Playback

1

kHz,

-8dBs (0.87Vp-p)

Audio Out

(pin (11) of El connector)

-

8 2

2dBs (0.7-l

or

.lVp-p)

Adjustment of audio bias current

1.

Put the unit in record mode.

2.

Connect an oscilloscope across the full erase

head.

3.

Make sure the erase voltage across the full

erase head is frequency is 70 +,

approx. 4OVp-p

5kHz.

Figure 2-2.

or more and

Measu ri ng

instrument

Mode

Input signal

Test point

Control

Specification

AC

milli-voltmeter

Osci

I

loscope

Record

I

Not required

I

TP6601(

I

R6623

I

2.6 & (7.6 +,

+ ) -

0.1 mVrms

0.3mVp-p)

or

TP6602( -

)

R

TROUBLESHOOTING

[

ELECTRICAL

VCR POWER TROUBLESHOOTING

The VCR is dead. (No power)

Unplug the AC power cord.

it a few minutes later.

I

L

Is the fuse

power

PWB 1

I

Are the AT normal in the VCR

Is the AT 5V linenormal

k_No

Are the AT 5V and properly connected with

I

Does pin

from * L w to * H ” level when AT 5V line changes OV to 5V with the AC cord being plugged in or ALL CLEAR button being pressed

and released ?

Does pin from m L - to ” H . level when the power button is pressed to turn the power on ?

Is the PC 9V line normal ?

Is the PC 5V line normal

I

Check wire harness to mechanism and the sensor inputs to

1

from mechanism (CAM Switches

1

startlend

I

F701

alright in the TV

J YES

m

12V

and ATBV lines

1

YES

(37)

of

ICBBOl

(24)

of

IC8801

5

YES

J YES

1

YES

sensors*and

PWB

?

YES

GND

lines

IC8801 7

change

YES

change

IC8801

reel sensor;)

Replug

7

?

OF VCR SECTION

TROUBLESHOOTING

I

No

I

NO

I

+I zecI!c;;i;he

Check fuse resistor and transistor trouble of the ower

Check/ Replace

~

Check pin

(PST529D2).

Check power key input to

p

and serial

IClOOl

Check

*

(26)

TV mother

I

FLOW CHART NO. l-l

I

Replace the fuse.

VCRPWB 1

ctrcurt m

Check poor soldering.

ICBBOl

and I or

(37)

of

IC8801

or

IC8802

IClOOl

clocks between

(L)

Signal at

and

4760

in the

and

4756

of

datasl

IC8801.

P-CON

IClOOl

PWB.

the

CASSETTE CONTROL TROUBLESHOOTING

\

A cassette tape Is not taken in.

YES

I

7

-,,

1

NO

-

I

NO

-

ND

__I___)

1

NO

-.

NO

Check between

NO

-

7

t

NO

___)

NO

-

I

Is the cassette housing

I

Does the start sensor cover

1

I

become open when the cassette tape is inserted

I

Does the start sensor pin (86) of

IC8801

go to “L’level when the

cassette tape is inserted

Does

pinJ5)

o to “H level (about

w

e cassette tape is inserte

I

Does

abou

is inserted

t

Is the correct loading terminal w tape is

Check and replace the loading motor.

I

Does start sensor pulse at pin (86) of

IC8801 than

level when t

I

Does end sensor pulse at pin (85) of

ICBBOl

when the cassette tape is loaded

Do the cam switches A and 8 operate

normall

loaded

(refer to MECHANISM flow chart)

I

of

in

(2)

of

P

11

V when the cassette tape

1

volta e at the

mserted 1

9,

change from I L l to ” H “level

when the cassette tape is

!

(at pins

Replace

distored 1

#NO

7

JYES

1

7

4

YES

lC8803 BA6209)

\

.8V

when

II

1

&YES

lC8803

go to

YES

a

en the cassette

$-YES

A cassette tape Is taken in, but ejected at once.

e from u L = to ” H e cassette tape is loaded

*YES

J-YES

(83)

and

(84))

+YES

lC8801.

Fix or replace the cassette housing.

Check the start sensor cover.

I

Check the start sensor and the way

up to pin

(86)

I

Check pin way up to pin

~

loading motor.

r

Check the start sensor and all the

way up to

Check the end sensor and all the way up to

Check cam switches and all the way up

*

to

Check

IC8801.

(8)

I(38803

lC8803

IC8801.

FLOW CHART NO.

of

IC8801.

of

IC8801

and all the

(5)

of

lC8803.

and AT12V line.

and the

FLOW CHART NO.

11

1

I

A

l-3

1

LOADING MOTOR AND EJECT

A cassette tape falls to eject.

I

TROUELESHOOTING

I

FLOW CHART NO.

l-4

SYSTEM CONTROL TROUBLESHOOTING

No power.

FLOW CHART NO.

1-5

#

Does the capstan motor start No when the EJECT button is pressed

Does the take-up reel disk turn when the capstan motor is running

7

YES

Is reelPluseat pin

when he take-up turning ?

”

H ” level (about

kb%{t;Cd8f03

Is about

11V

Is the correct voltage at the loading motor terminal

Does the loading motor run

Replace the cassette cam, gear, etc.

I

(58

of

IC8801

1

ree

disk is

1.8V)

1

YES

(10)

1

YES

of

1

at pin

lC8803 1

when reel pulse

at pin

IS

.

t

7

NO

No .

J

NO

p

NO

p

NO

7

____)

I

See FLOW CHART NO.

c

)

Check the reel disk and reel drive unit.

)

Check the take up reel sensor and all the way to

Check between pin

*

and all the way up to pin

IC8801.

$r~~~~C8803 and

Check between the way up to the loading motor.

Replace the loading motor.

IC8801.

(6)

of

lC8803 (7)

“L”

level of pin

lC8803

1-6.

of

and all

1

YES

Does power control pin

(24)

of

to

I

oressed?

Check peripheral circuit for poor soldering and wire harness to mechanism or the sensor input to

IC8801

“H”

level when power key is

Is the PC 5V line normal

from mechanism.

(H)

signal at

change from”L’

1

YES

NO

Check

IClOOl

and

lC8801.

Check

IC8801.

w

Check

Q9911,Q9912

and

1

I

49917.

CAPSTAN MOTOR TROUBLESHOOTING

The capstan motor fails to run.

FLOW CHART NO.

l-6

TAKE-UP REEL PULSE GENERATOR TROUBLESHOOTING

sensor pulse appears.

FLOW CHART NO.

1-7

Is the voltage more than about

2.6V given out of pin

1

Is 5V

at pin

I

Is

2.5V

at pin (4) of MC connector ?

Is the voltage more than about

2.6V given to pin

connector

1

r

Is the voltage at pin connector

I

Check/replace the capstan

I

7

1.6-2.7V

(7)

of

1

YES

t

(1)

of MC connector

1

YES

1

YES

(5)

of MC

1

YES

t

(6)

of MC

?

1

YES

lC77017

7

I

1

I-1

I

1

I

_

NO

Check

IC7701

*

to pin

I .

I

Check

+

(69)

to the 2.5V line.

I

Check between the MC

~

connector and

F

between the MC connector and

I

Che;.,pms

I

and all the way up

(3)

of

IC8801.

..

Check the

R7741, R7742,

of

IC8801

(2)

of

IC8801.

(S),(6)

:

Check the

PCSV

and al

IC7701,

and

ATl2V

line.

ins

P

the way up

and

(99)

line.

of

(70)

and

Insert the cassette, and

pu;;;e

unit in FF or

I

Are there the up/sup

ly

reel pulses at

P

the

I

HEAD SWITCHING PULSE TROUBLESHOOTING

I

L

D-PG =z2v

D+G m,-,---

t4’

col ectors

Q8802lQ880 1 ?

Are there the take

up/sup

ly

reel pulses at

P

the

col ectors

D8804/D8803 ?

Replace the up/supply reel sensors

D8804/D8803.

No head switching pulse.

lsthe

drum

rotating ?

I

of

NO

of

teke

!r-NO

YES

take

NO

REW

YES

I

Checkall

~

y-&31

Check between D8804

~

and Q8802, between

D8803 and Q8801.

I

1

;

See FLOW

I

thewauto

and (59rp0

FLOW CHART NO.

CHART NO 1

.

l-8

g.

-

I

t

Are the drum PG and

1

drum FG signal inputted YES to pins

(66)

and

(67)

1

NO

(3)

of

1

NO

of

7

IC8801,

L

I

respectively

Are there the drum PC and drum FG Signals at pins

(5)

and

connector E8

Check the harness EB-ME

and the drum motor unit.

YES

I

pulse.

Check

IC7702

~

way up to pins of

IC880 1.

and all the

(66)

and

(67)

I

Is the

voltoge

1 ?

-

volta

e more than about

-%

at pin

(4)

more than about

(1)

of

1

YES

t

(1)

of ME

of ME connector ?

YES

2.6V given out of pin IC770

I -

Is the

2.6V applre

connector ?

IS

12V

I

Check/replace the drum motor.

I

DRUM MOTOR TROUBLESHOOTING

The drum motor fails to run,

I

_

1 I

NO

No

Check

*

+

w

IC7701

to pin

(4)

I

Check between the ME connector and

IC770 1,

socket and pin

Check the

FLOW CHART NO.

I

and all the way up

of

IC8801.

and between the ME

(62)

of

IC8801.

ATl2V

line.

1-9

I

Is drum PC signal at pin ME connector

I

Is drum PC signal at pin

IC8801?

I5 H.

SW. pulse at pin

IC880

,

I

1 ?

Check pin

7

t

(62)

YES

of

The drum motor runsonly for a few seconds.

of

NO

I

*

Check the drum motor.

+

Check between the ME connector

;;t8;l,l

the way up to pin

Check or replace

(66)

(13)

of

IC8801.

(5)

of

I

FLOW CHART NO.

(66)

of

IC8801.

l-10

I

DRUM SERVO TROUBLESHOOTING

FLOW CHART NO.

1-l

1

tN0

t

Is there the drum

signal at pin

IC8801?

Check pin connector ME and the drum motor.

(3)

(67)

of

NO

of the

FG

I

In PB mode

YES

-

Drum servo does not function.

Is there 16MHz oscillation at ins and (39) of

Is the reference voltage

2.5V normal ?

I

ICE801 ?

YES

i

YES

1

YES

(38)

I c

$-

Is there the head switching pulse at pin

(13) of

IC8801

?

YES

Is there the drum control output at pin

(4)

of

IC8801

?

YES

NO

ND

NO

I

-11

+

See FLOW CHART

w

:-

CheckX8801, C8810

and

C8811.

NO.18

Replace

IC8801.

,“RECmode

Check the composite sync. signal at pin (25) of

IC2201

’

cl

-l

and

NO

1

42215.

zF;mk;ge

signal Ii ne of

-

Is there the drum

control voltage applied

topin(l)of

connector ?

Check and replace the drum motor.

*

v

ME

NO

Does the drum error amplifier circuit of

* (pins (11, (2) and (3))

operate normally ?

YES

Is pin

(62)

of

IC8801

Check IC7701.

1~7701

in high

,

NO

4

CAPSTAN SERVO TROUBLESHOOTING

Capstan servo does not function.

I

FLOW CHART NO. 1-12

A

0

I

Does PB

CTL

appear at pins (71) and

(72)

,

Does of

IC8801 (79)) operate normally ?

(Does the noise appear at pin (73) when touch

R7737

signal

of

IC8801

#NO

CFL

amplifier circuit

(pins (73) to

by hand

?

?)

Only PB mode inoperative.

Check

X8801, C8810

and C8811.

I

t

Check the capstan

signal line between EC

,YES

*

connector and

(through

I

Replace

IC8801

lC7702).

lC8801.

FG

.

6

1

J

I

Are

REC

mode inoperative ?

NO

Is there

oscillation at

and

(39)

Is 2.5V at pin MC connector ?

NO

Does there appear the capstan FG signal at pin (68) of

Is there capstan

r

+

control signal at pin

(3)

of

IC8801

Are pins(S),

(7)

of

Is pin normal ?

and /or

YES

16MHz

oins (38)

of I&801:!

I

+

YES

(4)

YES

7

IC8801

YES

i

?

YES

J.

(6)

IC7701

normal ? YES

J

(2)

of

IC8801

PB

of

?

and

’

NO

-

4

NO

.&+

Only

Check

~

r

R7741, R7742,

pins

(70) IC8801

up to the 2.5V line.

and (69) of

and all the way

Replace IC8801.

Replace

Replace IC8801.

REC

mode inoperative.

IC770 1.

0

Is there

YES

I

L I

REC CTL

signal output at pin

(77)

of

ICI8801

Check the composite sync. signal line between pin

IC2201

and Q2215 up

to pin

(93)

B

T

1

of

?

No

(25)

IC8801.

of

_I l_..-..---l-_-___l__

Is the harness

normal ?

Does the A/C head

operate normally ?

Adjust the height of the

AK

head.

I

t

YES

I

+

YES

EF-MH

-_--

NO

)

Replace the harness

MH.

NO

_

Replace

--

AIC

head.

-

EF-

Check

I

“@I.

1

Check

I

Replace the capstan motor.

I

“a..

In case of NO GOOD

i

I

VCR RECORDING MODE

(LUMINANCE)TROUBLESHOOTlNG

No record.

FLOW CHART NO. 1-13

VCR RECORDING MODE (CHROMA)

Record Is In black and white ( E-E

TROUBLESHOOTlNG

colour

mode

).

FLOW CHART NO.

1-14

1

Are there Y/C data and

clock signals at pins (14) and

(15)

of

IC2201

when

sta;::I

IC2201

(29)

?

YES

of

(26)

IC2201

and

NO

*

Check the

Check the signal line all

-

the way up to pin

of

1

Check the

*

line.

IC2201.

PCSV

line.

BIAS CTL

(52)

9V

,

f

Is there a signal at pin (2)

of

IC22011

1

YES

Is there a signal at pin

(18)

,

I

of

IC3301 (STV5715)?

YES

Replace

repectively

]1 recording

Is there a signal at pin (38) of

lC2201 1

1

YES

r

Is there a signal at pin

(52)

2

Is there a signal at pin

(18)

IS

level ?

I

of

IC2201 7

of

IC3301 (STV5715)?

I

1

YES

(2)

of 1~33019V

1

YES

NO

Is there 5V at pin

* (54)

Check pin and signal line.

7

Are there clock signals at pins (14) and

repectively

recording starts ?

No

NO

lsthere

*

and

Is there H. SW. pulse at pin

L

IC2201.

23

YIC

(15)

of

lC2201

when

5Vat

(54)

of

.

I

data and

YES

ins(26)

P

201

7

IC

1

YES

1

YES

NO

-

signals from

No

)

>

No

,

I

ABNORMAL

1

Check data and clock

Check the signal line all the way up to pin

IC2201.

;kzck

IC8801.

(2)

of

the H. SW. pulse

I

VCR PLAYBACK MODE (LUMINANCE) TROUBLESHOOTING

No Playback.

Are there clock signals at pins (14) and

iteaA;;vely w,,en playback

(15)

Y/C

of

data and

IC2201

1

I=+,,1

FLOW CHART NO. 1-15

VCR PLAYBACK MODE (CHROMA) TROUBLESHOOTING

Playback

lsin

black and white.

Are there

when playback starts?

I

Y/C

data and

FLOW CHART NO.

1-16

’

YES

t

Is there si

of

L

I

-I-!!%+

Replace

nal

at pin

YES

I

AYES

(13)3No

I

IC3301.

Is there 5V at pin

* IC3301

?

I

Is there H. SW. Pulse at pin (20) of IC330 1 ?

I

Check EH connector

I

Check peripheral circuit

of2~;; (47)

Check pin

-

I

4

and

(33)

YES

NO GOOD

(48)

of

(12)

of

I

NO

I

NOGOOD

I

of

IC2201. ’ NeG’JOD)

I

+

Check the H. SW. pulse line.

Check video head and/or

*

replace

IC3301.

IC2201.

Is there a signal at pin (15) of

I

IC3301?

is there a

of

IC2201

I I

Is there a

of

IC2201

I

Is there pin

(27)

Is there a pin (7) of El connector ?

1

YES

I

sim

?

1

YES

signal

?

t

chroma

of

IC2201

chroma

at pin

YES

signal at

?

YES

signal at

YES

(56)

Check the pin

ND

-

(Bias

CTL 9V

circuit of

Check

No

* topin(l5)of IC3301.

1

No

I

Is there H. SW. at pin

NO

-

of

lC2201

Check the signal at pin

(10)

of

(Frequency,

No

(2)

of

IC3301

line) and peripheral

IC3301.

theiignal

line all the way up

?

YES

IC2201

?

4.43

MHz)

I

.

(1)

is

OV

NO

*

ABNORMAL

t

1

Check

I

Check the chrome

rotation line.

Check Q22 14 and the signal line.

IC2202.

I

Check

422 14

ABJ

and

.

harness from f El to f

Check the signal line of the TV circuit.

J

I

1

Is there a signal at pin

+

(29)

of

IC2201?

I

YES

VCR E - E MODE TROUBLESHOOTING

No E- E signal.

NO

+

Check the harness from f AB J to f El J and input signal line.

I

FLOW CHART NO.

l-17

VCR SOUND TROUBLESHOOTING

I

< EE

Sound is not heard

I

EE

I

>

No Sound

<EE

1

(

REC >

I

Sound is heard But audio

posse ble >

REC

I

is not

Is there an Audio Signal at pin

IC66017

FLOW CHART NO.

<PB Sound is not heard

1

I

( PB

I

(7)

YES

)

,

NO

of

l-18

>

of

‘I

IC2201 7

42214

1

YES

and El

Is there a signal at pin

(27)

Check connector.

I

Is there Bias Oscillator

t

I

YES

ES

Y

I

.

YES

.

(11)

YES

signal at pin (6) and pin

(5)

of

T6601

Oscillator)

line between pin

of

Check pins

of

IC6601

IC660 1.

?

and Audio

(14)-(18)

1

NO

--t

%

of

7

Check the Audio mute circuit;

Is there an Audio

*

NO

I

Is there 5V at pins

w

and

(54)

Replace

I

of

IC2201

i

YES

i

IC2201.

(26) NO

7

I

Check the

+

PCSV

line.

Signal at pin

IC6601 7

Check the pin

Check

EE (L)

I

t

Check the signal line from TV mother

NO

i “H”

(22)

of

IC6601

46606

line.

Replace

(14)

of

level at

in

and the

IC6601. If-

PWB.

Is there an Audio

Signal at emitter of

46602.

v

Is there an Audio

Signal at pin

1

El .I connector

L

NO

(Bias

h

(18)

I--

Check

Is there an Audio

Signal at pin

IC6601 2

t

Is there an Audio

Signal at pin

lC6601 7

I

Check the pin

PB

mode.

Check the signal line between pin

(7)

-I

Q6602,46601

(8)

of

YES

(14)

of

YES

at

‘L’

(22)

of

level

of

IC6601

in

(8)

and

IC6601

and peripheral parts.

96603

and

NO

I

I-

46604.

Check the signal line to the TV main

I

PWB.

I

TROUBLESHOOTING OF TV SECTION

TV

TROUBLESHOOTlNG

I

Set not operating

TABLE

KEY-IN

FLOW CHART NO.

I

2-l

Key-in input for VCR is not received.

I

TROUBLESHOOTlNG

I

FLOW CHART

NO.24

1

NO

Is

F701

blown 14

YES

IC7Ol,L702 L703.

I

and

Is AC cord connected

Is AC applied to line between

(1)

and

?

IC701

1 YES

(3)

YES

?

A-connector ?

NO

Is

350

V DC applied to

c7071

1

Is16VDCappliedtopin No

(5)

of

IC701

Does pulse waveform exist at line between and

(2)

of

I

Check secondary circuits

of

D751--0755, L751,

FB751 -FB754.

of

(1)

7

NO

-

I

-

NO

__t

I

Connect AC cord.

AC cord broken.

Check

R702, R703

IC701.

Is 600 V DC ap lied to

line between 1) and

of

IC701

I

No

I

and

P

?

(2)

I ’

YES

I

Is the key switch in good contact ?No

Is there short-circuit in the key

input

?

1 YES

Are signals received at pins and

(16) IClOOl

activated 7

Check line of serial datas, serial clock and ready

I

Does the infrared remote control function

Is 5V applied at pin remote control receiver

IS

” L * pulse given out of pin (I)

of the receiver and

!‘,~~~~~~ll:;~~~~~a~~~red

$-YES ,

Is fluorescent lighting enough away from the set ?

t

Is there short-circuit in the key input or

I

IClOOl

(L)

.

7

IClOOl ?

when the key is

4

YES

,

IC8801

(2)

1 YES

received

+YES

i

YES

(1) (2) I NO

and signal

INFRARED WC

No operation is possible from the infrared remote control.

I

of the

7

at pin

NO

)

TROUBLESHOOTlNG

I

NO

)

NO

Reposition the set not to be

, I

Check the switch contact.

Check

*

IClOOl (iX2604CE)

switches for poor soldering.

Check key lines to input of IClOOl.

FLOW CHART NO.

I

Replace the infrared remote

*

control as required.

w Check the SV and

Check pin receiver.

+

exposed to strong light.

.

I

(5)

Check key input terminals.

GND

of IClOOl. and /or

and

lines.

2-3

1

I I

I

_ _ -. - _

.

--- --- ----

‘-----;;.-;-----1 I

I

k--------------,

TV TROUBLESHOOTING TABLE

I

NO RASTER

Normal

.f,,,

]

I

,

Replace the Fuse

I I

FLOW CHART NO. 2-4

I

Circuit to be checked:

1.

TUNER

2. PIF

3. ;z;;;,atic

4. 9V

noise increases but no signal is received

Is there a signal at pin (8) of

IC402 ?

j

adjacent parts.

gain

power source

I

NO PICTURE, NO SOUND

I

Does the noise level increase at max,

Contrast, Brightness, and Sound Control ?

ND Is there a signal at pin

- (8)

of

IC403

+

Check

IC402

and adjacent parts

?

YES

ND

FLOW CHART NO. 2-5

I

h

Is there a signal at

P

C302?

m (8)

of

YES

ND

-

A

L----------,--J

+

Check Tuner AGC.

IL ----_---.

-----

I

Check

IClOOl

:

-------- - -___

1

r-‘-“’

1

Check the IF

:

Pack.

L,-,--,,----,-JL

--““,r”“”

r r

Check

I I

line.

--mm-v.-e---,-J

i

“““1

thePC9V r

I

NO VERTICAL SCAN

I

lC801

(7)

bias check.

Normal

I

FLOW CHART NO. 2-6

NO PLAYBACK SOUND

I

Check the TV: TROUBLE

SHOOTING ‘NO SOUND’.

I

FLOW CHART

N0.2-9

check

r----‘--------“‘--‘-~ 1

Check the CRT connector

! Fl-F5

and adjacent parts.

L----------,--,,,,---J

j-1

,-- --_----_

, - -- - - - - -

I

Check

;

adjacent parts.

I----_---___~~_,~~,___1

t- - - - - - - - -

--‘ill!

IC351

and

Normal

-.

I

r !

NO SOUND

NO

Does waveform appear at

pin(8)oflC302?

I

I I

i----,-----,----,-----i

NO PLAYBACK PICTURE

I

1 YES

AYES

Check speaker.

Abnormal

r----“------“---‘--~

RSOl,DSOl,

I I

GO 1, C502

L,,,-,,----,,,,,,----J

(

I

I !

I I

FLOW CHART

FLOW CHART NO. 2-6

N0.2-7

Circuits to be checked:

0IC

801

and its Adjacent Circuit

0 R. G. 8.

Output

Ctrcuit

,------------------, ; IC801

; X801

(PAL

.------------------a

r-------I,,---,,,

I

Check

4852

1

adjacent circuits.

L------__----____a

17.7MHz)I;

and its

1

I I

r--------l---,---,

i ; L----------------..a

Check 0851 and its adjacent circuits.

r

YES

Is the white balance

properly adjusted

r----------------y

j

Readjust the white

;

balance.

L-----------------l

r--------L

i

I

Check Q853 and its

I

1

adjacent circuits.

I

L----------------d

FLOW CHART NO.

?

IN0

------_?

2-10

I

I I

i

I

OVERALL SCHEMATIC DIAGRAM

r-

I

H

G

FULL

ERASE HEAD

F

AUDIO CONTROL HEAD

HEDUOO63GE

VIDEO HEAD

HEDVO

I76GE

V-I--3428X

1

VT-5128X

Awxo ERAOE

AwIoa7AsElao *w10 a40 mxl

ClLtEM-

H

nxo

AWIO n3ll m ClLlEAD+

(NW-027

I

AJ

E

LOADING MOTOR

h4DTM I 062GE

-.

MOTN205

I GE

D

FJ-

-

I

I I

C

I I I

I

I I I

B

M56747FP

DRUM MOTOR DRIVER

DRUM MOTOR

MOTP

I I24GE

UN11

,-

I-

‘I---

,-

I

r

-

OCGlO704@5

-c4ulcoNlRoL

- ORW MOTOR 00

- MA4 FO

- AT IZV

-DRu(PQ

-DRWFopQW

-

AT sv

B

I I

I

A

I

-.

----------------________________________-----------------------------------------------------------------------------------.

1

I

2

1

3

I

4

I

5

57

I

6

I I

i

I

1 CNW-0264AJ

I

X

I

(*v )

-(FDQIS)

t CNW- I 894PE

I

CNW- I669PE

ti 1

DEFLECTION YOKE

DY60

I

CILHOOS~PENJ

X

CILH

l576CE

I

VI060

IN

___-----------___________

I I

I I I I

I I

I

I 1

I

I I

I I I

I I I I

I I

I

I I

iSCRIPT

WITH -

IONS

*-

I

7

I

8

I

9

I

10

I

11

I

12

I

58

CHASSIS LAYOUT OF TV SECTION

VT-3428X VT-51

28X

H

G

F

E

D

PWB-A

PC

0

El

4754

O/BN

In

BN/BN/BK

I

cl755

cl

IC351

Q706°0Q757

-hl

IC752

IC754

. - .

I

Q607

0

.

430

0

I

C302

t

4403 4402

00

0

4404

1

I

IC803

1

I

1

UNT20

4303

0

X801

9

0

IC802

IC301

1

clc

4302

I

IF

0

4306 T

0

Q204

540

1

P1

II

4756

41002

Xl001

cl

oIC1003

CFlOOl

II

R

1 III

-’

0’

n L602

1

L601

Q501

R/BN R

OQ1004

0

QlOOl

t

0Q4u 1

IC401

I

C402

0 0

4502

0

Q604

VIDEO

C

AUDIO

OUT OUT

PWB-B

l

C762

IO-

B

A

-

1

I

2

I

C702

T701

n

3

I

4

I

5

I

6

59

503

VT-3428X VT-51

28X

PWB-C

1 01r

‘5 4201

U

4202

PR701

001

PWB-D

t Y lB4

I_]

Q856

s1201

POWER

ALIM.

Q855

0

Q852

0

60 8854

0

Q851

0

PWB-F

\

cl

t&g

\

P;AY s l 204STOP/EJECT

cl

s1202

aam

REW

cl

S1205

cl

S1203

a/e

P1202

P

0

-I

7

I

8

I

9

I

10

I

11

I

12

I

60

BLOCK DIAGRAM OF TV SECTION

h

*ICI002

moM

0759 VT-REG.

I

VT-3428X

W-51 28X

IC803

R-Y. B-Y.

( )

AMP.

--(v-SYNC

--(H-SYNC

+H-DRIVE

-iFa,

I

-

I

1

I

ID602 7’

I

II

=

( H-SYNC/H-FLY IN

2

.

. .

I

D603

)-

I

3

9604

mOTECT --t~“TECT>-

61

I

4

I

5

I

6

f

I

!

i/T-3428X VT-5128X

-

AMP.

0401

VIDEO

IC35 I

AUDIO AMP.

IVE T

IC40 I

VIDEO SW.

030

AUDIO AMP.

MT20

IF PACK

I

tt

020

I

0202 0203

I

-----~--&-I our can

J

7

I

8

I

9

I

10

I

11

I

12

I

62

BLOCK DIAGRAM OF TV SECTION

I-

085

I

eO852.0853

VIDEO OUTPUT

0854.0855.0856

CUT OFF

POWER

PWB-8

I

0753

e

I

0751 0752 0761

RELAY SW. ON/OFF SW ON/OFF

DELEY

ERROR

c

DETECT

I I

IC702

PHOTO

I

COUPLER

T70

POWER

I

TR

m

1

I

2

I

3

I

4

I

5

I

6

63

VT-3428X VT-51 28X

VCR-KEY

POWER SW-R/C

---F-----P-----P---

IC70 I

~-----------------------------------, I

rl=qgg

l-

POWER CONTROL

MUVER

0°F

LATM

START

OSC

7mOER

I I

I

------

L

D70

l-4

RECTIFIER

t=l+/-

070

I

1,

YS

I

D705

L, I,

D706

ERROR AMP.

0702.0703

LATCH.

or04 OVP.

I

L702

I I

--m---v

ygE--+

I

(Al

1

L799

I I

I

I I

I

I I

I

I I

I

-m-w

I

----m---m---

I

7

I

8

I

~---~I~-~---~I

9

I

10

I

11

I

12

J

I

64

DESCRIPTION OF TV SECTION

SCHEMATIC DIAGRAM

SAFETY NOTE:

1.

DISCONNECT THE AC PLUG FROM THE AC OUTLET BEFORE

REPLACE/NC

2. SEMICONDUCTOR HEAT SINKS SHOULD BE REGARDED AS

POTENTIAL SHOCK HAZARDS WHEN THE CHASSIS IS

OPERATING.

IMPORTANT SAFETY NOTICE:

BE SURE TO USE GENUINE PARTS FOR SECURING THE SAFETY AND RELIABILITY OF THE SET. PARTS MARKED WITH “A y (

FOR MAlNTAlNING THE SAFETY OF THE SET. BE SURE TO

REPLACE THESE PARTS WITH SPECIFIED ONES FOR MAINTAINING THE SAFETYAND PERFORMANCE OF

SERVICE PRECAUTION:

THE AREA ENCLOSED BY THIS LINE( - - - - - - -)

DIRECTLY CONNECTED WITH AC MAINS VOLTAGE.

WHEN SERVICING THE AREA, CONNECT AN ISOLATING TRANSFORMER BETWEEN TV RECEIVER AC LINE TO

HAZARD OF

PARTS.

) ARE IMPORTANT

THESET.

IS

ELIMiNATE

ELECTRICSHOCK.

VT-3428X

VT-51 28X

CAUTION:

This circuit diagram is original one, therefore there may be a

slight difference from yours.

NOTES:

7.

The unit of resistance “ohm N is omitted.

(K

=

1000

ohms, M = 1 Meg ohm).

2. All

resistors are

l/8

watt, unless otherwise

noted.

3.

The unit of capacitance

(/1= puF,P =

4.

The values in parentheses are the ones in the

PB

mode; the values without parentheses are

the ones in the

,@J

REC

“F”

mode.

is omitted.

VOLTAGE MEASUREMENT CONDITIONS:

1.

DC voltages are measured between points

indicated and chassis ground by

AC 1

lo-24OV, 5Ol6OHz

supplied to unit and all controls are set to normal viewing picture unless otherwise no ted.

2.

Voltages are measured with

co/our signal.

VTVM,

7OOOOpV

B&W or

with

WAVEFORM MEASUREMENT CONDITIONS:

lOOOO@,

is fed into tuner.

87.5% modulated

co/our

bar signal

65

VT-3428X VT-51 28X

SOLID STATE DEVICE BASE DIAGRAM

-TOP

iX2448CENl FX0030CE BA7655

1

2SK304CD

VIEW

l-4

8

iX1495BM

1 3

2x3198 2SA1271 2SAl266 2SC3279N 2SC383 2SA988

1

iX2604CE

2sc2229 2SA1321 or 2SA1371 2SC227 1

R

L

BASE

L

COLLECTOR

1

EMllTER

2sc3399 DTC144ES

40

32

1

ix1 566BM

0

0 0

21

20

II M II

B

C E

2SD1877 2502095

f

1

vvvvvvvu

STRM6523

TA7348P

Ill-l Ill-i

1

TA7812S TA7805S

1

J

9

WT.33

SE1 15N

TDA7056A

9

l-7

ix1 163BM

2SD1944

66

1 AC: l.OVp-p

0

DC : 5.0 V

0

6

AC :

1.9 Vp-p

DC:

lS5V

0

2AC:

0

7

AC : 2.2 Vp-p

WAVEFORMS (VT-3428X)

1.3

DC

:

DC:OV

3.2

Vp-p

V

0

3

8

AC: 1.7Vp-p

DC :

3.2

V

AC:1.7

DC:2.4

Vp-p

V

0

4

AC: 1.7Vp-p

DC :

1.55 V

9 AC : 50 Vp-p

DC:

52V

0

5AC:

1.7 Vp-p

DC:1.55 V

0

11

AC :

DC:OV

950

Vp-p

0

12

I

AC :

DC:OV

I I I I I I I

6.2 Vp-p

0

13

AC:71Vp-p

DC:

128V

0

14

AC:71Vp-p DC:

128V

0

15

AC: 8OVp-p

DC:

128V

67

VT-3428X VT-5128X

AC :

0.9

0

1

Vp-p

DC : 5.0 V DC : 3.2 V

2 AC: 1.3Vp-p

0

I

7

0

WAVEFORMS

AC :

2.2 Vp-p

DC:OV

(VT-51

28X)

I I I I I I I I I-

11

AC :

950

0

DC:OV

Vp-p

VT-3428X VT-51 28X

MODEL VT-3428X SCHEMATIC DIAGRAM: Mother Unit

TO PWB-E

(EE)

..-------------------------------------------------,

I I I I I I

Rlun ;

,I( 4hM,o1003

2SC3

(25Cl815-

1

I984

0404

2X3198-G

l2SC I B

15-C)

1

I

2

I

3

I

4

I

5

I

6

69

M--3428X VT-5128X

1

1c35 1

II

TDA7056A

-TO

PWB-E

(Eli

- - --

-

0302

I

I I

2SC3

(2SC 18

198-G

I%G)

ii i

I

(TP1001)

70

MODEL

I-

H

G

F

VT-3428X

SCHEMATIC DIAGRAM: CRT Socket,

Powe

E

POWER

D

@

*iI2”

TO

PWB-A

C

TO

PWB-A

B

MOTOR

UR 20” “CR

B

I

“CR

No,,‘:

M

3

I I

I

A

1

I

2

I

3

I

4

I

5

I

6

c

71

VCR-Key

1

and

Power SW, R/C Unit

NOTE:. I. THE UNIT’ OF RESISTOR

2.

ALL RESISTORS ARE I/BWATT. UNLESS OTHERWISE NOTED.

3.

ALL CAPACITORS ARE

tK=

IO00 OHMS.

M=MEGAOHMI.

JJF.

UNLESS OTHERWISE

- OHM

-

IS OMITTED

TO PWB-A

NOTED(P=uuFl.

TO PWB-A

IPEZZ I

-o--p7

--m-

I

b-7 NC

@-8

-W.-----o

8

I

9

-------m-m-_

I

10

J

I

11

I

12

1

72

MODEL VT-5128X SCHEMATIC DIAGRAM: Mother Unit

TO PWB-E

(EE)

H

G

IC I002

IX2448CENI

EEPROM

F

E

TO

PWB-0

@iii&

D

C

r

0403

0402

2SAl266-Y 2SC3198 l2SA1015-Yl lZSC1815

B

0404

2X3198-G

(25C I6

15-G)

I

A

PWB-c

04)

t

h

I

2

I

3

I

4

I

5

I

6

73

1

IL

IC35 1 TDA7056A

.TO

PWB-E

IEII

TP1001)

EXT-

YYNTRot Gm

so1

!

- -“~~-- ~~I-o- I WT

OIIT

I

7

I

8

I

9

I

10

I

11

I

12

I

74

MODEL

--

VT-51 28X

SCHEMATIC DIAGRAM: CRT Socket,

Powe

TO PWB-A

POWER

(F)

P-

075

I

TO PWB-A

1 I

2

I

3

I

4

I

5

I

6

c

75

r(CR-Key

and

Power SW,

‘NOTE: I. THE UNIT OF RESISTOR

(K=

IO00 OHMS.

2.

ALL RtSISTORS ARE I/BWATT.UNLESS OTHERWISE NOTED.

3.

ALL CAPACITORS ARE

M=MEGAOHMl.

PF,

UNLESS OTHERWISE

R/C Unit

*

OHM -IS OMITTED

TO PWB-A

NOTED(P=uJJF).

VCR-KEY

PWB I202 OPWBFB735PEi

-------m----m

~-~-----~---~-~-~-

PWB70

I OPWBFB732PEZZ

LTSS

A

;I cILGo36aE +

02

1207cE

76

W--3428X VT-51 28X

oe

0-e

TUN

o+

AGC

5............55........5........

~

.:.:.:................................::..::...:..:........:.:.......

~:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:,:.:.:,:.:.~:.:.:.:.:.:.:.:.:.~:.~:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.~:.:

Bu

. . . . . . .

.ii 2.5 .

. . . ...z...

. . .. . .....i...........

. . .. . . . . . . .

..f5555.......

.

..T. ..5...

o+

BL

o+

$j

BH

Infrared Remote Control Unit

VTSS8S2D

) RRMCGI 176PESA 1

1

I

2

I

3

I

4

I

5

I

6

1

77

m-3428X VT-51 28X

IF-Pack Unit

4?

11

l

e

i

t

) RiWOOl7CEZZ

1

I

2

I

3

I

4

I

5

I

6

1

78

CHASSIS LAYOUT OF VCR SECTION

PWB-E

II

TP2208

VIDEO OUT

0

EE

EG

TP2203 TP2204 H.SW TP2205

PB CHROMA

P

GND

EB

0

Q2214

cl

Cl2215

:c220 I ,*\

‘ ‘\

I

i

\

’

X5502

I’

‘I

=-‘i

IC3301 :

I

--_-_- -__I

08804

END SENSOR

J

I

S.U.REEL

SENSOR

D8803

.

-.

79

VT-3428X VT-5128X

TP660 TP6602 BIAS(-)

@--$~&

1660 I n”

IC660

I

I------

I

l

I

L----J

I

1

I BIAS(+)

0

Q6605

I

EF

D8805

CASSETTE LED

S8203

gzD~

I- s-VOL -I

VOLUM

II

+v

TP8804

NON

TP8805 CAS-CON

IC8802

cl

S8204 S8206

UP

I

a

VOLUME

A v A

S8205

“3

I

CANALE

CH

UP

pJ

CANALE

I

2

CAM SW A

08804

T V REEL SENSOR

0830

POWER

WAKE-VP

C!i/,VEGl

.I

IC770

I

I--;

I

m-m

EC

i-i

I

D8302

REC LED REGI

Q8803

START SENSOR

HEAD SWITCHING

08303

TIMER

IC8803

AGGI

PG

cl

ED

09913

D8304 u

CHILD LOCK

ij

0991

I

!”

IC990 I

I

-

7

I

8

I

9

I

10

I

11

I

12

1

80

BLOCK DIAGRAM OF VCR SECTION

H

4

OVERALL

G

F

E

BLOCK

8

------I

_

DIAGRAM

WMTUER

h

DEKmuAloR

VIDEO s1ouAL

DUFUY PROESS

i

-

IC402 VIDEO SELECT SW

Tu(ER

! -L++ IAllx~

L--

’

A0

5 lvcs

IEC

D

VmEo DFVT

-(

Auom

m

a

3

*ux.mDEo

a

I

-10

*-

C

-(

M

3

M

a

B

A

1

I

2

I

3

I

4

I

5

I

6

81

VT-3428X

VT-5128X

AWIO m

I

Au)10 f&X

I

7

I

8

I

9

I

10

I

11

I

12

I

82

BLOCK DIAGRAM OF VCR SECTION

H

SERVO PROCESS BLOCK DIAGRAM

W--3428X VT-51 28X

r----------d

I I

I

---_-----------_----__________I

I I

I I I

1

I

2

I

3

I

4

I

5

I

6

83

VT-3428X VT-51 28X

-___-__---___

10.0

1

rl--'"

i CAPSTIH UDTOR UllT I --____-_--__----___--------~

I

0

I

7

I

8

I

9

I

10

I

11

I

12

1

84

BLOCK DIAGRAM OF VCR SECTION

m SYSTEM CONTROL BLOCK DIAGRAM

VT-3428X VT-51 28X

c--

@ij B f t&t

A

--------

4

1

I

2

I

3

I

4

I

5

I

6

85

VT-3428X

VT-5128X

n

SAFETY DEVICE BLOCK DIAGRAM

I

.--. -----me----

4L

rdl

&-----A---;

aI8

rie f

I

7

I

8

I

9

I

10

I

11

I

12

I

-

u. ,c

I

,D

I

ea

I

n

I

u

I

m

I

n

I

GI

I

FULL

MAD

AU010

MAO

All010 HEA0

IDAY

ERASE

I

AU)10

PROCESS

PC=-4

0

z

‘CC

BIAS

QEN

a

+

“SPaJ

v--m

/LP.zi

,

cn 9v

AT SV

SYSTEM CONTROLLER

XC8801

MANUAL SYSTEM IS

0Y TV DATA FROM

TRANSFERED

TV.

I’220

I 37PIN

SECAM DET. (H)

FROM

ICZZO I 25PIN

COMPOSITE SYNC.

MC

FROM CAPSTAN MOTOR

FROM CTL HEAD

MH

2

CTL@

MH

I

CTL

@

EF

3ifi$02215

EC

+Jc

mLIc7702

EF

V-SYNC.

SEPARATOR

CAP.

FG

SHAPER

--$+

4

3.9K

’

-u-u-

l-V-4

JlJJ

2v

t-

e

AUTO SYSTEM IS TRANSFERED

BY

SYS-CON DATA TO TV.

SIG.6OHz 5v

6

GENERATOR

08815

SIG.SOHz

LPfHl

TO VIDEO AUDIO BLOCK

;

MESECAM (H)

1

b

PB

PS

AMP

:ON

25 or 3OHr

CTL

4

I - !

AUTO SYSTEM SELECT

*

-

BLOCK DIAGRAM OF VCR SECTION

H

4

VIDEO SIGNAL FLOW BLOCK DIAGRAM

G

I I

Aw.

1

0

1

F

LIN. Qy.

I

;I;

E

D

C

B

A

1

I

2

I

3

I

4

I

5

I

6

89

VT-3428X VT-51 28X

I t

7

I

8

I

9

I

10

I

11

I

12

I

DESCRIPTION OF VCR SECTION

SCHEMATIC DIAGRAM

SAFETY NOTES:

1.

DISCONNECT THE AC PLUG FROM THE AC OUTLET

BEFORE REPLACING PARTS.

2.

SEMICONDUCTOR HEAT SINKS SHOULD BE REGARDED

AS POTENTIAL SHOCK HAZARDS WHEN

OPERATING.

THE

CHASSIS

IS

VT-3428X VT-51

28X

NOTES:

The unit of resistance “ohm ” is omitted (K =

7.

M = 1 Meg ohm).

2.

All resistors are I/ 16 watt, unless otherwise noted.

3.

The unit of capacitance “F’is omitted & The values in parentheses are the ones in the PB mode;

4.

the values without parentheses are the ones in the mode.

VOLTAGE MEASUREMENT CONDITIONS:

DC voltages are measured between points indicated and

1.

chassis ground by VTVM, with supplied to unit and all controls are set to normal viewing picture unless otherwise noted.

2.

Voltages are measured with

signal.

WAVEFORM MEASUREMENT CONDITIONS:

1OOOOpV 87.5

tuner.

CAUTION: This circuit diagram is original one.

a slight difference from yours,

percent modulated colour bar signal is fed into

AC220-240V, 50Hz

1OOOOpV

B & W or

Therefore there may be

=pF,

1000

p =ppF).

ohm,

REC

colour

91

VT-3428X VT-51 28X

WAVEFORMS

v:

tovp-p

P In

(20)ot IC2201

REO/EE

Y/C

n-J--i

+-Hi4

v: 4.wp-p

P In

(26)ofIC2201

COMPOSITE SYNC.

SERVO

~nrvl

H: 76OHz (SP) V: ZSVp-p p In

(68)ofIC8B01 REC/PB

CAPSTAN FG

v: 22vp-p

P In

(27)oC XC2201

RECEE

Y/C

ml

+-IV-+

V :

JOOmVp-p TP2203 PS

CHROMA

SERVO

-z

G2v 4

v: zwp-p

P In

(73)of IC8601

PB

CTL

V :

600mVp-p

P In

(38)ol XC2201

REC/EE/PB

H/A H/A

r

$-IV-+

v: 2sOmvp-p

P In

(18) olIC3301

REC

SERVO

V: A8Vp-p

p In

(93)o t IC8801

EE

.(REO)

v-SYNO

V: BOOmVp-p Pln (2)ofIC2201 REC/EE

v: l.ovp-p

P In

(63lot IC2201

PB

SYSTEM CONTROLLER

V : P In

PE

SERVO SERVO

LJ--lSE

+ 2v -+

V: 4.2Vp-p Headmltohlng pulse Pin (18 of REC/PB

IC3301

v: 6.ovp-p p In

(3Wot I08801

REC/PB

CLOCK

V: 4.2Vp-p

p In REWPB

DRUM PO

AUDIO AUDIO AUDIO

H: 70?rSkHz

V: 28mVma TP6601 (+) TP6602 (-) REC

w

Ii:

IkHz

V: ‘LbVp-p

P In

Wof

oonneotor-EI oonneotor-EI

REWEWPB

H: IkHz v: 13vp-p

P In

REWE WPB

H: 000Hz

ti: 70tSkHz v: 7ovp-p

P In

oonneotor-EF REC

HZ 4.43MHZ

v: 1evp-p

P In

(10)of XC2201

l--LnnJ

P In

(67)ot ICB801

REC/PB

AUDIO

(2101

700mVp-p

(6l)ot XC2201

E

t66)ofIC8601 v: 4.4vp-p

4A?

(Il)of

DRUM FQ

92

?

--SCHEMATIC DIAGRAM: VCR Unit-l

H

E% FizEz Y-D- -m

-----------------------------------------,

G

F

TPPOI Lo343oE

I

.

FP

VT-3428X

I

VT-51 28X

3

TO SYSTEM CONTROL.SERVOWCRI

E

D

C

I

B

A

1

I

2

I

3

I

4

I

5

I

6

93

VT-3428X W-5128X

3

7

I

8

I

9

I

10

I

11

I

12

I

94

SCHEMATIC DIAGRAM: VCR Unit-2

PWB-E

(F5 I67AJ)

VT-3428X VT-51 28X

J

-

1 ~*,

JLOADING MOTOR

1

j

1

w3

VOLTAGE SW

REC

mAwo1 XmXI-w T DlEn

1

I

2

I

3

I

4

I

5

LED TIMER CHILD

DRIVE

LED DRIVE

I

LEO DRIVl

6

LOI

95

VT-3428X VT-51 28X

.

TO

Y/C.AUDIO

CIRCUIT

NCR

21

I

7

I

8

I

9

I

10

I

11

I

12

I

96

1

PRINTED WIRING BOARD ASSEMBLIES

H

TV SECTION

H

G

F

W-3428X VT-51 28X

8

PWB-A: Mother Unit (Wiring Side)

1

I

2

I

3

I

4

I

5

I

6

I

97

VT-3428X VT-51

28X

_^.^ “x------I

PWB-D:

-“..” .--. ”

1

Power SW, R/C Unit

(Wiring Side)

PWB-F:VCR-Key

7

I

8

I

9

I

10

I

Unit (Wiring Side)

11

I

12

I

98

VT-3428X VT-51

7

W

TV SECTION

28X

/

H

G

F

E

PWB-B:

D

C

B

Power Unit (Wiring

Side

^ -~. -_-

A

-

1

I

2

I

3

I

4

I

PWB-C:

5

CRT Socket Unil

I

6

1

7

:.

99

m-3428X VT-51 28X

:/Wiring f!

r

Side)

7

I

8

I

9

I

10

I

11

I

12

1

100

SHARP VT-3428X, VT-51 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual