SHARP VT-3428X, VT-51 Service Manual

SERVICE

MANUAL

TV/VCR COMBINATION

VIDEO TV

Chassis No.

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

TV/VCR Integration for Easy Operation Single Built-in Tuner for Simple Operation

n

Timer Programme Setting by the On-Screen

Display

Auto Tracking Control

n n

n

Auto Head Cleaning System

On-screen Display with Menu Screen Guidance

Wake-Up/Sleep Timer

Simple Playback

n

Lock Operation Mode Lock the Power Off.

n

System)

n

Full Auto Play Function

n

Auto Repeat Playback

n

Front input terminals Audio/Video

CONTENTS

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

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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 .

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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

SPECIFICATIONS

I

Number of Video Heads I

Model

Reception channels

VHF band

UHF band

Receiving System

Antenna input

Audio output

Speaker

Rated voltage

Rated frequency

Power consumption

Video cassette format

Video recording system

Video signal

Screen

cm “Viewable” measured

diagonally,

I

W

deflection

Two rotary heads, helical scan

VHF :

UHF :

MHz

ohm unbalanced

8 cm round type x 1

: Sl

PAL B/G

PAL

Max.

V

Hz

standard

2

PAL

MHz

cm “Viewable” measured

diagonally, 90’ deflection

W

V

28X

MHz)

I

Recording/playing time

Tape width

Tape speed

Operating temperature

Storage temperature

Weight

Dimensions

Video input

output

Audio input

output

Supplied accessories Operation manual, wireless remote control unit,

*Design and specifications are subject to change without notice.

kg

PAL

x

minutes max. with

:

x

mm

1 1

jack:

to

battery x 2

mm

playback only)

kg

x

ohm

1

tape

MOD)

x

mm

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,

connecting a probe) between picture tube be disconnected from AC outlet.)

Picture tube in this receiver employs integral implosion protection. Replace with tube of the same type number for continued safety. Do not lift picture tube by the neck.

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

the high voltage completely.

k ohm Resistor in series with an insulated wire (such as a test

and

remove static charge from it by

anode lead. (AC line cord should

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:

than than

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

been factory

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

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

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

excess X-ray radiation.

(at beam 0 (at beam 0

+

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

-Adjusted to the above-mentioned high voltage.

(at beam

for the set. for the set.

in the case of the set. The set has

in the case of the set. The set has been

fluctuates as a result of the repairs, never

BEFORE RETURNING THE RECEIVER

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

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.

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

(Forward video

search) BUTTON

28X

POWER

SENSOR ARE FOR REMOTE CONTROL

VIDEO INPUT JACK AUDIO INPUT JACK

NOTES:

l Use the RESET button if the

Timer, etc.) cannot be operated.

1

mode (ex.

Program

. . : :

STOP/EJECT

(Reverse video

i

search) BUTTON

0

BUlTON

MAIN POWER SWITCH

VIDEO OUT JACK AUDIO OUT JACK

ANTENNA IN TERMINAL

POWER/WAKE-UP

TIMER INDICATOR

VOLUME UP/DOWN BUTTONS

CHANNEL UP/DOWN BUl-t-ONS

0

1

l

A V

A

MAIN POWER SWITCH

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

Slide off

Slide on

Open the battery cover. (Remove any old

batteries that may be in the remote control.)

( + and

w ab ) with the markings inside the compart-

Insert

ment.

Replace the cover.

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

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

TIMER

SELECT

buttons

TIMER ON/OFF button

PAUSE/STILL button

COUNTER RESET button

EJECT/LOAD button

MUTE button

DISPLAY button

VOLUME ADJUSTMENT buttons

CHANNEL UP/DOWN buttons

(TRACKING buttons)

PROGRAMME button

MENU button

SET button

STOP button

PLAY button

button

Video Search

Reverse

DISASSEMBLY AND

n

TV SECTION

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

Disconnect the F connector from the main the anode cap and the CRT PWB unit from the CRT. After disconnect the coating earth from the CRT unit and take out the unit.

Remove the two screws from the main PWB and separate the

Remove the three screws from the power

and G connector from the power

from the video unit.

and separate the

from the video unit.

and disconnect

6

DISASSEMBLY AND REASSEMBLY

(Continued)

Remove the CRT PWB,

the main PWB upright.

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

coil connector G and front power switch remote control

coil connector G off position.

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.

-Mother

FRONT

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

cables start repairing.

(AD) and (PC) to the mother

assembly from the

to

TV Unit

l PRECAUTIONS

Calling the service mode

ADJUSTMENT OF THE

TV ELECTRICAL CIRCUITRY

Hold down the POWER button ( of the set. Now the set is in the service mode.

UP key

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

Clearing the service mode

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

Display in the service mode

ROM No. in the microprocessor

Adjustment item Nos.

L---l

data

2

*SERVICE MODE :

MODE :

*SERVICE MODE

*SERVICE MODE :

*SERVICE MODE

*SERVICE MODE :

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

RED

INT

BLUE INT

HI-VI

electable

= = =

= O-63

= =

=

= O/l

by the

General adjustment items

Basically fixed

Variable by the VOL key

key

8

SCREEN/BACKGROUND ADJUSTMENT

.

Adjusting Conditions

Adjusting Procedures

Screen Adjustment

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

background off.

Reset “video adjust” mode.

t

Call the service mode and take the step below.

Screen control: Look at the control so that the

turn from to

data on the screen. Adjust the

figure from left should

To be 0 here too.

To turn to 0 here.

Background Adjustment

Receive

PATTERN” signal.

In the video adjust mode, adjust the brightness

and contrast.

Bright portion:

l Dark portion:

Keep the colour adjusted at “00”.

“WHITE BALANCE ADJUSTMENT

nit

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

The be used as a colour thermometer.

temperature as follows.

=

y =

CRT Color Analyzer” should

and

Focus Adjustment

Receive “monoscope pattern” signal. Reset the video adjust mode to have the Video

Normal Position.

Adjust the focus control to have the best focus in

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

Adjust point

9

HORIZONTAL/VERTICAL CIRCUIT ADJUSTMENT

Figure

I

Receive “PAL monoscope pattern” signal. Reset the video adjust mode to have the Video

Normal position.

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

l

Select the service mode number

l

Select the service mode number

Adjusting Conditions

Adjusting Procedures

(vertical size):

Adjust the

to have 10% overscan.

(vertical linearity):

Adjust the

to have optimum vertical linearity. (See

Figs. 1 and

l

Select the service mode number “6”. Adjust the

center of the screen. (See

l

Select the service mode number

(vertical center):

so that the vertical center be at the

Fig.

(horizontal center):

Adjust the

.

. . . . . . .

Figure

.

,

.

l ‘

,

center of the screen. ( See

Fig.

Figure

PURITY ADJUSTMENT

Adjusting Conditions

Before the purity adjustment, warm up the set

with beam current of more than 700

longer than

I

a

b

model).

Receive the qreen-only signal and adjust the

beam current to about 770

minutes (400 PA for the

(500

for the

model).

Fully

the CRT with the

for

coil.

Figure A.

Left

.

,

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

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

I I

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

\

Beam landing equally outwards.

Figure

Left

. . . .

\

I

, ,

I

.. . .

.

Beam landing shifted to the right.

Figure

Left

.

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

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

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

.

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

.

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

I

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

I

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

I I

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

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

... .

. . . . .

.

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

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

\

.

. . . . .

Right

.

. .

1

I

,

I I

I

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

,

Right

Adjusting Procedures

Notes:

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.

Observe the spots “a” and

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

positions.

If the right and left spots are

outwards from their landing positions (shown in

Fig.

push the deflection yoke forwards for

proper positioning.

If both the spots are shifted to the right or left

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

positioning.

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.

If any

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

forwards.

Landing too inwards : Deflection coil to backwards.

Receive the monoscope pattern signal. Set the raster rotation at

facing the east.

Adjustment error: 0

Tighten up the deflection coil screws.

Tightening torque:

(shown in Fig. A)

deviated

adjust the opening

as

well as the right

position with the set

2 mm

2 kg

I

Beam landing shifted to the left.

Figure

CONVERGENCE ADJUSTMENT

Adjusting Conditions

This adjustment should be performed after

the purity magnet adjustment.

Receive the crosshatch pattern signal. Set the brightness and contrast controls to the

0 and 1 O/l 0 positions, respectively.

Figure a.

Figure

Wedge

..I..........

magnet

Figure

. . . .

Figure

magnet

I

.

I

.

I

.

I

.

CRT neck

Adjusting Procedures

STATIC CONVERGENCE

I

.

Adjust the opening angle of the

magnet

and rotate the magnet to impose the blue line

I

over the red one.

Adjust the opening angle of the

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

DYNAMIC CONVERGENCE

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

Stick the above wedges on the CRT, and apply

glass tape over them.

Apply lacquer to the deflection yoke screw, the

magnet unit (consisting of purity,

pole magnets)

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

and

in position, and tilt

deeper, and tilt the

for correct convergence.

and

magnet unit screw.

Do the

Purity magnet

Lacquer

A/V Output Checking

PERFORMANCE CHECK

Adjusting Point

output

Adjusting Conditions

Receive the

modulation). Add a Add a

The output levels are as follows.

Note:

Make sure the video and audio outputs are as specified.

ohm terminal resistor to the video output terminal.

Video output: Audio output:

bar signal

terminal resistor to the audio output terminal.

1

3

Procedures

white

bar, audio : 400 Hz, 100%

A/V Input Checking

I

Receive the Feed the external video and audio signals via the Using the

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

bar signal.

front jacks.

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

Protector Performance Checking

Protector

Performance

Receive the monoscope pattern signal.

Apply

symbol on the

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

Note:

To reset the protector, press the

from the constant-voltage power supply to the cathode of

and make sure the protector is not activated.

Beam Protector Performance Checking

Beam Protector Performance

Receive the monoscope pattern signal. Ground any of the Make sure the protector is activated immediately.

Note:

To reset the beam protector, press the RESET key.

G and B cathodes on the CRT PWB.

no

PERFORMANCE CHECK

Blue Background Checking

Adjusting Point

Blue background

Record Index Checking

Record index

In the SET UP mode, select the BLUE SCREEN function. Turn on the function. With any signal input,

Make sure also that the audio is mute.

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

In the SET UP mode, select the Turn on the function to make recording. (Make sure the clock has been preset.) Check the recorded contents.

Note:

Make

the channel and time

Adjusting Conditions

INDEX function.

recoded.

(Continued)

Procedures

make sure the background is blue.

PRECAUTIONS IN REASSEMBLING

MOUNTING THE

Initial setting is indispensable

made in two ways; electrical and mechanical.

CONTROLLER

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

Electrical setting:

Make a short-circuit between TP8804 and TP8805, both located at the center on your side on VCR with a the cassette controller in position. (This method is used when the mechanism has been already set on its

ohm resistor and be sure that the mechanism is back to its initial setting position

Now place

Mechanical setting:

Cassette control

drive gear

Phase matching point

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.)

Now place

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 Reconnect the

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

cables

and EH) and harnesses (ED and

between the mechanism and VCR

Parts to pay attention to:

Start and end

Record tip switch:

Take special care of the MC-EC connector

(board

and VCR

to

board) between

the mechanism

I

FUNCTION OF MAJOR MECHANICAL PARTS

Drum Motor

Auto Head Cleaner

Take-Up Pole

Drum

Full Erase Head

Supply Pole Base

Main Supply Brake Lever

Tension Arm

Base 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

n

No.

Full erase head Erase the whole records on the tape in the recording mode.

Tension arm

Detects the tension of tape while running, and brakes

the supply reel disk via the tension band.

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

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

Function

Take-Up

Lock Lever

Loading

Motor

No.

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

Pinch roller lever

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

A motive power which drives the mechanism. It

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

Function

Reel Disk

FUNCTION OF MAJOR MECHANICAL PARTS

Capstan

Motor

Reel Belt

Slow Brake Lever

Master Cam

Cassette Housing Drive Gear

(BOTTOM VIEW)

Take-up

Loading Gear

Shifter

Connect Gear 5

Clutch Gear

No.

Slow brake lever Gets in contact with the capstan

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

certain degree. Capstan

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

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

motor

Function

motor linking to

\

Reel Pulley

No.

Reel pulley Transmits the power of the capstan

reel disk via the reel idler.

Shifter Transmits the operation of the master cam to break

and loading gear.

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.

Clutch Connect Arm

Function

motor to the

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).

NECESSARY FOR ADJUSTING THE MECHANICAL UNITS

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

Jig Item

Reel Disk Height Adjusting Jig

1

Master Plane Jig

2

3

A/C Head Tilt Adjusting Jig

4

Gauge Head

5

Part No. Code

I I

AW

Configuration

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.

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)

Tension Gauge Adapter

This cassette torque meter is used

I

for checking and adjusting the torque of take-up for measuring tape back tension-

There

are two gauges used

tension measurements, 300

These Jigs are used for loosening or

tightening special hexagon type

screws.

These tapes are especially used for electrical fine adjustment.

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

for the

and

No.

Jig Item

Part No. Code

Configuration

Remarks

Special Bladed Screwdriver

Torque Driver

Box Driver

Reverse Guide Height

Adjusting Jig

AR

AS

C

:

1

This screwdriver is used for adjusting the guide roller height.

This is used to screw down

made parts: the specified torque is

This Jig is used for height

of the A/C head and X-

position.

This Jig is used for replacement of the

roller.

This Jig is used for height adjust-

ment of the reverse guide.

This Jig is used for height

of the reverse guide.

MECHANICAL PARTS REQUIRING PERIODICAL INSPECTION

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

Guide roller

Supply impedance roller

(inner hole and shaft)

Supply impedance roller flange

Retaining guide

Slant pole

Video head (upper/Lower drum

Full-erase head

A/C head

Capstan

Pinch roller

Reel belt

Motor

q q q 0

q cl 0

cl

cl cl cl El

cl q

cl

0 Cl 0 Cl

0

q q

cl 0

cl q

0 No tape running, tape slack

Possible symptom encountered

q

Lateral noises Head occasionally blocked

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

Poor

0

Sound too small or distorted

0

No tape running, uneven

No tape running, tape slack, no

0

fast forward/rewind motion

beating

Remarks

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.

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

Tension band

Loading Motor

Reel idler

Reel

Clutch gear

Main supply/take-up brake levers

NOTE:

(Automatic Head Cleaner)

Part replacement.

:

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

q

A

0 0

0

Cassette not loaded or unloaded

0

No tape running

0

0 Tape slack

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

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.

roller

,

REMOVAL AND REASSEMBLY OF

CASSETTE HOUSING CONTROL ASSEMBLY

l

Removal

Set the cassette ejected condition in the cassette

eject mode. Unplug the recorder from the main source. Follow the procedures below in the specified

order.

a) Remove the cassette housing installation

screws

Slide and pull out the cassette housing control

assembly upward.

and

.

\

Cassette control drive gear

Follow the procedures for removal in the reverse

order.

I

Drive angle of cassette control

Figure

Notes:

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

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

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.

Load the cassette once onto the cassette housing

control assembly after reassembly.

Figure l-l.

l

Reassembly

Before installation of the cassette housing

control assembly, make a short-circuit between 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.

with a

ohm

TO RUN A TAPE WITHOUT THE CASSETTE

HOUSING CONTROL ASSEMBLY

Be sure to make a short-circuit between TP8804

and side on the VCR

before turning on the power. Plug in the power cord. Turn on the power switch. Open the lid of a cassette tape by hand.

Hold the lid with two pieces of vinyl tape.

Set the cassette tape in the mechanism chassis.

Stabilize the cassette tape with a weight

to prevent floating. Perform running test.

Weight to prevent

Note:

The weight should not be more than

both located at the center on your

with a

Figure

ohm resistor,

REPLACEMENT AND HEIGHT CHECKING

AND ADJUSTMENT OF REEL DISKS

l

Removal (Supply and Take-up reel disks)

Remove the cassette housing control assembly. Pull the tension band out of thetension arm. Remove the supply main brake and the take-up

main brake.

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

remove the reel disk.

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)

Clean the reel disk shaft and apply oil to it. Install a new take-up reel disk onto the shaft. 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

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

Figure

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

Figure

l

Reassembly (Supply reel disk)

Clean the reel disk shaft and apply oil to it. Install a new supply reel disk onto the shaft. 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.

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

Figure

l

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

part

If the height is not correct,

readjust the reel disk height by changing the

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

Master plane

.

Reel disk

Figure

Reel disk height

adjusting jig

Mechanism chassis

I

l

Adjustment

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

the capstan

motor pulley, reel belt and reel

pulley with cleaning liquid, then recheck the

torque.

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

the reel belt.

Notes:

Hold down the torque gauge so that it may not

fly off.

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 REWIND MODE

Remove

the

cassette housing control assembly.

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

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

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

Setting

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

button to set the mechanism to the

fast forward mode.

Checking

Turn the torque gauge slowly (one rotation

and

Make a short-circuit between

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

Setting

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

on the supply. reel disk. Press the REW button to set the mechanism to the rewind mode.

Checking

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

and

every 2 to 3 seconds) by hand in the take-up direction. Check to see if the take-up torque is higher than

I

or more

its maximum value.

(Red mark)

3

Take-up direction

Figure

is held at

Figure

The guage is held at its maximum value.

l

Adjustment

If the

the capstan

torque is outside the range, clean

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

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

the reel belt.

Notes:

Hold down the torque gauge so that it may not

fly off.

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. Make a short-circuit between

on the VCR

with a

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

hold it with two pieces of vinyl tapes. Load the cassette torque meter into the unit. Put the weight (5009) on the cassette torque meter. Press the

button to put the unit in

mode.

and

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

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

l

Setting

Push the PLAY button to place the

playback mode.

Push the

video search reverse mode.

l

Checking

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

gfcm)

Torque

button to place the

2 seconds) and

check that the

and

in the

Set value

Figure

0.

Checking

Check that the torque is in the range of 8.8

39gfcm). The torque fluctuates due to the rotational deviation of the reel pulley

Use the center of the fluctuation as the value. Place the

in the SP record mode, and check

that the take-up torque is within the range.

Adjustment

If

the take-up torque in the playback mode is

outside the range, replace the reel pulley

Note: Stabilize the cassette torque meter to prevent floating.

Supply reel disk

Figure l-l

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

in video search reverse mode

is outside the range, replace the reel pulley

Note:

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

the fluctuation at the value.

Use the center of

CHECKING THE FAST FORWARD BACK TENSION

l

Remove the cassette housing control assembly.

l Make a short-circuit between

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

l

Checking

I. Push the

fast forward mode.

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

button to place the

(I 5

Torque gauge

Supply reel disk

Figure

2.

Note:

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.

and

in the

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

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

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

weight exerted on the reel disk.

(I 3

8

CHECKING THE VIDEO SEARCH REVERSE

BACK TENSION

Remove the cassette housing control assembly.

Make a short-circuit between

both located at the center on your side

on the VCR

with a

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

Torque gauge

,

and

in the

.

weight exerted on the reel disk.

CHECKING THE REWIND BACK TENSION

l

Remove the cassette housing control assembly.

l Make a short-circuit between

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

l

Checking

I. Push the REW

rewind mode.

Torque gauge

Take-up reel disk

to place the

l-l

,

and

in the

Take-up reel disk

Note:

Set the t

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

weight not exerted on the reel disk.

gauge securely on the take-up

CHECKING THE PINCH ROLLER PRESSURE

l

Remove the cassette housing control assembly.

l Make a short-circuit between

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

l

Checking

Push the PLAY button to place the playback mode.

and

in the

Visually check to see if the left end of the tension

Tension gauge

,200 g

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

required in the following steps.

left of

Pinch rolle

Capstan shaft

Detach the pinch roller from the capstan shaft. Set the tension gauge by hooking the tension

gauge adapter onto the pinch roller shaft.

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.

Check that the reading of the tension gauge is in

the range of 900 to

Tension gauge adapter

Figure

CHECKING AND ADJUSTMENT OF TENSION

POLE POSITION

l

Remove the cassette housing control assembly.

Tension

0.2mm

I

Center line

Figure

Make the adjustonent with the beginning of a

tape.

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

pole

l Make a short-circuit between

and

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

l

Setting

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

with two pieces of vinyl tapes. Load the cassette tape into the unit. Put the weight Make the adjustment with the beginning of a

E-l 80 tape.

l

Checking

Set a cassette tape, press the

the tape loaded. Now check the tension pole position.

on the cassette tape.

Figure

button and get

Figure

Remove the cassette and press the

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

Place the cassette in position and check the

tension pole position.

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

I

.

i

I

0

button to

I I

Figure l-l

Remove the cassette and press the

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

Place the cassette in position and check the

tension pole position.

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.

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

@Adjustable range of the tension pole positioning

cam.

\

Tension arm shaft

arm

meter

Figure

l

Checking

Push the

button to place the unit in the

record mode.

Check that the back tension indicated by the

gauge is within the set range

to 38 g-cm.

Notes:

Make sure that the video cassette tape is over

the retaining guide.

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

Adjustment

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

toward A.

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

Tension pole adjusting cam

Figure

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

left and right

from the tension arm shaft’s center.

CHECKING AND ADJUSTMENT OF RECORD

l

Remove the cassette housing control assembly.

l Make a short-circuit between

on the VCR

turn on the power.

l

Setting

Open the lid of the cassette torque meter, and

hold it with two pieces of vinyl tapes. Load the cassette torque meter into the unit. Put the weight (5009) on the cassette torque

meter.

PLAYBACK BACK TENSION

and

both located at the center on your side

with a

ohm resistor. NOW

Figure

I

CHECKING THE BRAKE TORQUE

l

Checking the brake torque at the supply side

,

Supply reel disk

5mN.m (SO-1

Figure

l

Remove the cassette housing control assembly.

l

Remove the cassette housing control assembly.

the brake torque at the take-up

5mN.m (SO-1

Figure

side

l Make a short-circuit between

and

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

Setting

Set a torque

on the supply reel disk. Switch from the Disconnect the AC power plug.

l

Checking

Slowly rotate the torque gauge in the clockwise

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

direction is at least twice as high as that in

the

gauge to zero on the scale. Place it

mode to the STOP mode.

and that the brake torque in the

direction.

direction

direction =

l Make a short-circuit between

and

both located at the center on your side

on the VCR

with a

ohm resistor. Now

turn on the power.

Setting

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

on the take-up reel disk. Switch from the Disconnect the AC power plug.

l

Checking

Slowly rotate the torque gauge in the clockwise

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

torque in the

high as that in the

l

Adjustment of the brake torque at the supply

mode to the STOP mode.

direction is at least twice as

and that the brake

direction.

direction=

direction =

side and the take-up side

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.

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

and the brake torque checking.

REPLACEMENT OF A/C (Audio/Control) HEAD

Remove the cassette housing control assembly. Place the unit in the unloading mode, and

unplug the power cord.

l

Removal

Loosen the tilt adjusting screw Remove the azimuth adjusting screw Remove the Unsolder the A/C head PWB soldered to the A/C

head assembly.

Notes:

After replacement, be sure to perform the

adjustment of the tape drive train (see page

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

finger, with alcohol.

Take care that the azimuth spring does not fly

off when removing the A/C head screw.

head screw

adjusting nut

Figure

l

Adjustment

head tilt angle]

Set the mechanism to the loading mode.

Place the A/C head tilt adjusting Jig

Slowly turn the tilt adjusting screw

screw driver until there is no gap between the Jig and the

head.

A piece of white paper

visuality of a gap)

with a

A/C head

Pay attention to

Figure

l

Replacement

Solder the removed A/C head

onto a new

head assembly.

The A/C head assembly is attached so that the

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

A/C head

New

A/C head tilt adjusting jig

head arm

Tilt adjusting screw

Screw driver

head

Figure

Never

touch the

A/C head plate

Figure

[A/C head height rough adjustment]

l

Setting

Box driver

Figure

HEIGHT ADJUSTMENT OF REVERSE GUIDE

[Height adjustment of reverse guide]

Reverse guide height

guide

Reverse guide height

adjusting jig

Go-end is mm. Not go-end is

mm

Figure

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

side first and then rotate the height

adjusting nut by

turn counterclockwise.

Actually load the unit with a tape, put it in the

play mode, and make sure the tape is free from

wrinkles near the reverse guide.

Use a commercially available box driver to turn

the height adjusting nut.

(a))

Figure

adjust the height of the A/C head by 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.

playback

mode.

Adjustment

Figure

Adjust the nut visually so that the control head is visible

to

below the bottom of the tape.

Box driver

Height adjusting nut

Figure

ADJUSTMENT OF TAPE DRIVE TRAIN

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

and

on the VCR

with a

ohm resister. Now

turn on the power.

Check and adjust the position of the tension pole. (See page 26.) Check and adjust the video search rewind back

tension. (See page

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

Rough adjustment of tape drive train.

a) Connect the oscilloscope to the test point for

envelope output (TP2203). Set the synchronism of the oscilloscope to EXT. The

signal is to be triggered by

the head switching pulse

Loosen the setscrew at the lower part of the

guide roller, and adjust it with an adjusting screw driver

so that the guide

roller turns smoothly. (Do not overloosen the

setscrew, which causes insecurity of the guide

roller.) (See Figure

Set the alignment tape (monoscope pattern)

on the reel disk, and place the unit in the

playback mode.

(Place a

g weight on the cassette tape to

prevent floating of the cassette tape.)

Guide roller

Wrinkles at upper flange

Wrinkles at lower flange Counterclockwise

Figure

Clockwise

Notes:

Place the tracking control in the center position,

and adjust the X-position adjusting nut so that the

envelop becomes maximum for

easier rough adjustment of the tape drive train.

In the rough adjustment, pay particular

attention to the outlet side.

Figure

In the X value adjustment mode (see the

Electrical Adjustment), change the envelope

waveform from MAX to

by pushing the ( + ) or

and

to MAX

tracking button, and

check a flat response is obtained on the

waveform.

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.

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.

Wrinkles at the upper flange : Turn the

above adjusting screw clockwise, as shown in Figure

Wrinkles at the lower flange

(a).

Turn the

above adjusting screw counterclockwise, as

shown in Figure

Loosen the setscrew

Figure

X-position adjusting nut

Figure

Head switching pulse

envelope

Figure

Adjustment of A/C head height and azimuth

Connect an oscilloscope to the audio output

terminal.

Use the alignment tape and play back its

audio 6

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

audio 1

signal (colour bar for video signal) 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

After this adjustment, apply

again.

to the

screws and nuts to fix them.

Box driver Azimuth adjusting screw

Figure

.

Adjustment of tape (VROUBZFS) drive train and

8

A/C head height

adjusting screw

nut

Figure

X-Position.

Connect the oscilloscope to the test points

for

envelope output. Set the synchronism of the oscilloscope to EXT. The

signal is to be triggered by

the head switching pulse

Play back the tape drive train alignment tape. Push the

or

button to change the

envelope waveform from MAX to MIN, and

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,

the

waveform will take the shape shown in Figure Adjust for maximum flatness of the envelope as the step 6,

in page 31.

.

Adjustment

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

Supply side

Take-up side

Supply side

Take-up side

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

Take-up side guide roller rotated in

clockwise direction

(lowers guide roller) to

flatten envelope.

Figure

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 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.

Push the

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

guide roller setscrew in the unloading mode.

Play back the tape drive train alignment tape

to check that the envelope waveform does

not change.

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

and

both located at

with a

ohm resistor to center the tracking.

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.

Adjust the playback switching point.

Check the flatness of the envelope waveform

and sound by playing back a recorded tape.

X-position adjusting nut

Main chassis

Figure

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

Remove the cassette housing control assembly.

Removal (Follow the order of indicated numbers.)

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

Remove the reel belt

Remove the screws

l

Reassembly

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.

Attach the reel belt. Reconnect to the board-to

board connector on the VCR

Notes :

After installing the capstan

to rotate the capstan

motor, be sure

motor and check the

movement.

Check the servo circuit.

REPLACEMENT OF D.D. MOTOR

Put the unit in the cassette eject position. Unplug the power cord.

l

Removal (Reverse the order in reassembly.)

Disconnect the Unscrew the stator assembly fixing screws Take out the stator assembly Unscrew the rotor assembly fixing screws Take out the rotor assembly

Notes:

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

Be careful not to lose it. 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.) Be careful not to damage the upper drum or the video head. Be sure that the hall device and the assembly are not damaged by the rotor assembly or other parts. After installation, adjust the playback switching point.

cable

2

Figure

motor

Figure

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).

Mounting the shifter (on the back of the

mechanism chassis).

Mounting the master cam (on the back of the

mechanism chassis).

Mounting the connection gear, slow brake and

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

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.

Pinch drive cam Pinch roller and pinch double-action lever Open lever

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.

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

Pinch Drive Cam

Figure

Insert Pinch Roller/Pinch Double Action Lever

Ass’

Pinch Roller Pinch Double

Phase-Matting Point

Figure l-48-2.

Action Lever

Insert Open Lever.

Figure

Mounting the shifter (on the back of

the mechanism chassis)

Drum

,

I

Capstan

Motor

Reel Pulley

0

(Bottom Side of mechanism chassis)

Figure

Insert

Cut Washer

,

Insert

Insert Point

Point

Make sure that the loading gear is at the point

as shown below.

Place the shifter in position, keeping in mind

the

insertion points and the

relief points.

For the phase matching at the insertion point

see the point

as shown below.

Finally fix the shifter with two washers located

on insert points

Phase-Matching Point

\

and

Figure

Mounting the master cam (on

the back

of the mechanism chassis).

Make sure beforehand that the shifter is at

the point as shown below.

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

E-ring.

\

Master Cam

Housing

Drive

Figure

Mounting the connection gear, slow

brake and loading motor assemblies

(on the back of the mechanism chassis).

Assemble the connect gear. Assemble the slow brake. 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

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.

When these actions are made smoothly, return the

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

REPLACEMENT OF LOADING MOTOR

l

Removal

Remove 2 screws.

Adjust the worm gear’s thrust gap to 0.05 to

mm.

Use the specific washers for an appropriate

Figure

l

Replacement

Take out the old loading motor. Place a

replacement loading motor as shown above (Figure

O.lmm

To press the motor in,

receive it by portion A.

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

0.05 mm away from the motor.

(10 kgf). Be sure that the pulley is

ASSEMBLY OF CASSETTE HOUSING

Drive Gear R and Drive Angle

Apply grease

Phase Matching Point

l Fix the drive angle ass’y to the

drive gear

shown in the figure.

Drive gear

Drive angle

Insert the jig shaft.

Gear, Drive Gear Land Drive Gear

Stamp mechanism code

R

\

Top

surface should be free from scraches or soil.

Phase Matching Point

Figure

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

In such a case, the phase needs

rematching.

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

symbol. Do this alignment for

both the drive gears.

jig shaft.

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:

signal generator

Dual-trace oscilloscope

milli-voltmeter Frequency counter Blank video cassette tape

l

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

n

SERVO CIRCUIT

ADJUSTMENT

@Screwdriver for adjustment

bar generator

@Alignment tape

style.

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 being pressed down more than 3 seconds. Play the alignment tape

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

playback mode. (See Note below.)

Connect a dual

points

(Trigger the oscilloscope with the head switching pulse on Adjust head switching pulse is the vertical sync as shown in Figure

Dual-trace oscilloscope

Playback

Alignment tape

(Video out) to

head switching point

adjustment control

H (lines)

button on the front panel is

button on the remote control to set

(Video out) and

so that the leading edge of the

(lines) ahead of

1

and press

to the test

2

HEAD .

SWITCHING

PULSE

Figure

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 (Mechanism operating mode, in this case the

SERVICE mode is not needed.

button is pressed after the

JUMPER) short

(lines)

is removed and the AC

.

V-sync.

and

n

Test points layout of VCR Main Unit.

0

5 “REEL

Adjustment of PAL System

still picture

vertical jitter

Measuring instrument

Mode

Cassette

Test point Adjusting point Specification

Play back the

System

Using the

remote control , make adjustment so that the

vertical jitter.becomes minimum.

Now press the STOP button to stop the tape.

Monitor TV

I

LP record/Still picture playback

PAL self-recording tape

I

Monitor TV screen

I

buttons.

No Vertical jitter.

self-recorded tape in the PAL

mode.

buttons on the

Figure

I I I

I

Adjustment of

System

still

picture vertical jitter

Measuring instrument

Mode Cassette Test point

Adjusting point

Specification

Play back the

System still mode.

Using the

remote control , make adjustment so that jitter becomes minimum.

Now press the STOP button to stop the tape.

Note :

of the vertical jitter adjustments are

memorized to the

Monitor TV

Still picture playback

I

Monitor screen

I

No Vertical jitter.

I

recording tape

recorded tape in the

buttons on the

on the TV main

buttons.

I I

I

AUDIO CIRCUIT

Checking of audio playback level

Measuring instrument

Mode

Input signal

Test point

Specification

Playback the Alignment tape.

level adjusting signal)

Connect an AC milli-voltmeter to the Audio

Out (pin

Make sure that the output level is

AC

I I

Playback

Alignment

Audio Out (pin

9

of

connector).

level adjusting signal.)

of El connector)

1

or

9

Checking of audio record level

Measuring instrument

Mode Input signal

AC

I I

Record/Playback

1

-8dBs (0.87Vp-p)

or

1

Connect an AC milli-voltmeter to test points

+ ) and

(Use Set the unit in recording mode. Adjust R6623 so that the signal level is

for ground lead.)

Checking of erase voltage and oscillation frequency

Measuring instrument

Mode

Test point

Control Specification

Put the unit in record mode.

Connect an oscilloscope across the full erase

head.

Make sure the erase voltage across the full

erase head is frequency is

Oscilloscope

Record

I

Full erase head

I

1

I

or greater

or more and

I I I

I

Test point

Specification

Connect an AC milli-voltmeter to the Audio

Out (pin

Feed the audio signal shown in table to the

AUDIO IN jack and put the unit A/V input

mode.

Make the self-recording and playback the

recorded portion of the tape.

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).

Audio Out

(pin (11) of El connector)

8

of El connector).

.lVp-p)

Adjustment of audio bias current

instrument

Mode

Input signal

Test point

Control

AC

I

Record

I

Not required

I I

+ )

or

)

Figure 2-2.

Specification

TROUBLESHOOTING

[

ELECTRICAL

VCR POWER TROUBLESHOOTING

The VCR is dead. (No power)

OF VCR SECTION

I

FLOW CHART NO. l-l

I

CASSETTE CONTROL TROUBLESHOOTING

A cassette tape Is not taken in.

FLOW CHART NO.

Unplug the AC power cord.

it a few minutes later.

I

Is the fuse

power

I

Are the AT normal in the VCR

Is the AT

Are the AT properly connected with

I

Does pin from

AT

line changes the AC cord being plugged in or ALL CLEAR button being pressed

and released ?

Does pin from the power button is pressed to turn the power on ?

Is the PC

Is the PC 5V line normal

I

Check wire harness to mechanism and the sensor inputs to

from mechanism (CAM Switches

L

to

L - to

alright in the TV

and ATBV lines

?

YES

linenormal

YES

and

of

lines

change

H

level when

to

YES

change

H . level when

YES

line normal ?

YES

reel sensor;)

with

I

NO

Replace the fuse.

Check fuse resistor and transistor trouble of the ower

Check poor soldering.

Check pin

Check power key input to and serial

and

Check pin

of

TV mother

I

of

clocks between

P-CON

and

and I or

or

Signal at

in the

the

Is the cassette housing

Does the start sensor cover

1

I

become open when the cassette tape is inserted

I

Does the start sensor pin (86) of

go to “L’level when the

cassette tape is inserted

YES

Does

o to

e cassette tape is inserte

Does is inserted

Is the correct loading terminal w tape is

Check and replace the loading motor.

Does start sensor pulse at pin (86) of level when t

Does end sensor pulse at pin (85) of when the cassette tape is loaded

Do the cam switches A and 8 operate loaded

(refer to MECHANISM flow chart)

I

of

level (about

in

of

V when the cassette tape

change from

when the cassette tape is

(at pins

go to

YES

en the cassette

$-YES

A cassette tape

e from

L

e cassette tape is loaded

Replace

to

L l to

J-YES

and

when

H

H “level

YES

NO

I

NO

1

NO

Check between

taken in, but ejected at once.

NO

I

Fix or replace the cassette housing.

Check the start sensor cover.

Check the start sensor and the way

up to pin

I

Check pin way up to pin

Check

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

of

and all the

of

and AT12V line.

and the

FLOW CHART NO.

1

I

1

LOADING MOTOR AND EJECT

A cassette tape falls to eject.

I

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

YES

NO

FLOW CHART NO.

I

.

See FLOW CHART NO.

Check the reel disk and reel drive unit.

SYSTEM CONTROL TROUBLESHOOTING

No power.

YES

Check

FLOW CHART NO.

and

1

I

Is reel

when he take-up turning ?

H

level (about

Is about

Is the correct voltage at the loading motor terminal

Does the loading motor run

Replace the cassette cam, gear, etc.

at pin

of

disk is

when reel pulse

at pin

YES

of

YES

IS

NO

J

NO

I

Check the take up reel sensor and all the way to

Check between pin and all the way up to pin

Check between the way up to the loading motor.

Replace the loading motor.

of

level of pin

and all

Does power control pin

of

to

level when power key is

I

Is the PC 5V line normal

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

from mechanism.

signal at

change from”L’

YES

NO

Check

and

CAPSTAN MOTOR TROUBLESHOOTING

The capstan motor fails to run.

FLOW CHART NO.

TAKE-UP REEL PULSE GENERATOR TROUBLESHOOTING

sensor pulse appears.

FLOW CHART NO.

Is the voltage more than about

at pin

I

Is

at pin (4) of MC connector ?

Is the voltage more than about

connector

Is the voltage at pin connector

I

Check/replace the capstan

I

of

YES

t

of MC connector

YES

of MC

YES

t

of MC

?

YES

I

NO

Check

to pin

I .

I

Check

to the 2.5V line.

I

Check between the MC connector and between the MC connector and

I

and all the way up

of

Check the

of

Check the

and al

and

line.

ins the way up

and

of

line.

and

Insert the cassette, and

unit in

or

I

Are there the up/sup

I

HEAD SWITCHING PULSE TROUBLESHOOTING

I

the

Are there the take

up/sup

the

Replace the up/supply reel sensors

No head switching pulse.

I

rotating ?

I

reel pulses at

of

NO

reel pulses at

of

NO

drum

YES

take

YES

I

Check between D8804

and Q8802, between

I

thewauto

FLOW CHART NO.

CHART

.

I

t

Are the drum drum to pins

Are there the drum PC and drum pins connector

Check the harness EB-ME

and the drum motor unit.

and

signal inputted YES

and

respectively

and

of

NO

Signals at

of

NO

I

YES

pulse.

Check way up to pins of

and all the

and

DRUM MOTOR TROUBLESHOOTING

The drum motor fails to run,

I

FLOW CHART NO.

I

Is the

1 ?

more than about

of

YES

t

Is the

connector ?

IS

I

Check/replace the drum motor.

I

Is drum PC signal at pin ME connector

I

Is drum PC signal at pin

e more than about

at pin

of ME

of ME connector ?

YES

The drum motor runsonly for a few seconds.

I

of

I

1 I

NO

No

NO

Check to pin

I

Check between the ME connector and socket and pin

Check between the ME connector

and all the way up

of

and between the ME

of

Check the

I

Check the drum motor.

the way up to pin

line.

FLOW CHART NO.

of

I

SW. pulse at pin

1 ?

,

Check pin

I

of

NO

Check or replace

t

of

I

DRUM SERVO TROUBLESHOOTING

FLOW CHART NO.

1

Is there the drum

signal at pin

Check pin connector ME and the drum motor.

of

NO

of the

In

Drum servo does not function.

I

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

Is the reference voltage

mode

I

YES

I

Is there the head

switching pulse at pin

Is there the drum

control output at pin

of

YES

?

YES

?

YES

I

NO

ND

NO

See FLOW CHART

CheckX8801, C8810

and

Replace

,“RECmode

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

NO

and

signal Ii ne of

Is there the drum

control voltage applied

ME

connector ?

Check and replace the drum motor.

NO

Does the drum error amplifier circuit of

operate normally ?

Is pin

YES

of

Check IC7701.

,

in high

CAPSTAN SERVO TROUBLESHOOTING

Capstan servo does not function.

I

FLOW CHART NO. 1-12

A

0

I

Does appear at pins (71) and

,

Does of

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

signal

of

amplifier circuit

(pins (73) to

by hand

?

Only

mode inoperative.

Check and C8811.

I

Check the capstan signal line between EC connector and

(through

I

Replace

Are

and /or

mode inoperative ?

YES

Is there

oscillation at

.

I

and

Is 2.5V at pin MC connector ?

NO

Does there appear the capstan pin (68) of

Is there capstan

r

control signal at pin

of

Are pins(S),

of

Is pin normal ?

of I&801:!

I

YES

of

YES

signal at

YES

?

YES

and

normal ? YES

of

NO

Check

pins up to the 2.5V line.

Only

and (69) of

and all the way

Replace IC8801.

Replace

Replace IC8801.

mode inoperative.

Is there

YES

signal output at pin

Check the composite sync. signal line between pin

to pin

B

0

of

?

and Q2215 up

of

Is the harness

normal ?

Does the A/C head

operate normally ?

Adjust the height of the

head.

I

YES

I

YES

NO

Replace the harness

Replace

--

head.

Check

I

Check

I

In case of NO GOOD

Replace the capstan motor.

I

VCR RECORDING MODE

No record.

FLOW CHART NO. 1-13

VCR RECORDING MODE (CHROMA)

Record Is In black and white ( E-E

FLOW CHART NO.

mode

Is there a signal at pin (38) of

YES

Is there a signal at pin

of

Is there a signal at pin

of

IS

level ?

I

YES

of 1~33019V

YES

Are there Y/C data and

clock signals at pins (14) and

recording

NO

Is there

of

Check pin and signal line.

of

when

at pin

YES

of

?

and

NO

Check the

Check the signal line all

the way up to pin

of

Check the

line.

9V

Are there clock signals at pins (14) and

recording starts ?

,

Is there a signal at pin (2)

of

YES

Is there a signal at pin

of

,

YES

NO

and

Is there

L

I

data and

of

when

YES

5Vat

7

of

YES

SW. pulse at pin

YES

NO

signals from

,

I

ABNORMAL

Check data and clock

Check the signal line all the way up to pin

the

of

SW. pulse

I

1

Replace

.

VCR PLAYBACK MODE (LUMINANCE) TROUBLESHOOTING

No Playback.

Are there clock signals at pins (14) and

of

data and

YES

1

FLOW CHART NO. 1-15

VCR PLAYBACK MODE (CHROMA) TROUBLESHOOTING

Playback

Are there

when playback starts?

black and white.

I

data and

FLOW CHART NO.

Is there at pin

3

of

YES

I

Check and harness from to .

El

Is there

I

Is there pin (20) of IC330 1 ?

I

Check peripheral circuit

Check pin

?

Check

at pin

YES

SW. Pulse at

YES

connector

I

NO GOOD

and

of

I

NO

I

Check the line.

Check video head and/or

replace

SW. pulse

Is there a signal at pin (15)

I

of

is there a

of

I I

Is there a

of

I

Is there pin

Is there a pin (7) of El connector ?

Check the signal line of the TV circuit.

I

?

of

?

YES

at pin

YES

signal at

YES

?

signal at

1

Check the pin

ND

(Bias line) and peripheral

circuit of

Check

I

Is there

of

Check the signal at pin

of

(Frequency,

of

line all the way up

SW. at pin

?

YES

?

MHz)

I

.

is

NO

ABNORMAL

Check

I

Check the chrome

rotation line.

Check Q22 signal line.

and the

I

Is there a signal at pin

of

I

YES

I

NO

VCR E

E MODE TROUBLESHOOTING

No E- E signal.

Check the harness from

I

to

El

and input signal line.

FLOW CHART NO.

VCR SOUND TROUBLESHOOTING

I

Sound is not heard

I

No Sound

(

I

Sound is heard

But audio

I

is not

Is there an Audio Signal at pin

1

(

FLOW CHART NO.

,

of

YES

NO

Is there a signal at pin

of

Check connector.

I

YES

and El

Is there Bias Oscillator

Is there an Audio Signal at pin

Is there and

I

at pins

of

Replace

YES

7

I

Check the

line.

Check the pin

Check

line.

I

Replace

t

Check the signal line from TV mother

of

NO

level at

in

and the

Is there an Audio

Signal at emitter of

Is there an Audio

Signal at pin

El

YES

ES

of

I

.

YES

Y

.

connector

YES

signal at pin (6) and pin

of

Oscillator)

line between pin

Check pins

of

(Bias

and Audio

1

NO

of

Check the Audio mute circuit;

h

Check

Is there an Audio

Signal at pin

Is there an Audio

Signal at pin

I

Check the pin

mode.

Check the signal line between pin

of

and peripheral parts.

of

YES

of

YES

level

and

of

in

and

NO

I

at

I-

Check the signal line to the TV main

I

TROUBLESHOOTING OF TV SECTION

TV

I

Set not operating

TABLE

FLOW CHART NO.

KEY-IN

Key-in input for VCR is not received.

I

FLOW CHART

I

NO

Is

blown

YES

and

Is AC cord connected

Is AC applied to line between

A-connector ?

NO

Is

Does pulse waveform exist at line between and

I

Check secondary circuits

of

and

V DC applied to

of

?

of

YES

?

of

NO

I

Check

Is 600 V DC ap lied to

NO

line between

of

I

Connect AC cord.

AC cord broken.

and

?

I

YES

I

Is the key switch in good contact

Is there short-circuit in the key

input

Are signals received at pins and

activated 7

Check line of serial datas, serial clock and ready

Does the infrared remote control function

Is

applied at pin

remote control receiver

IS

L

of the receiver and

$-YES ,

Is fluorescent lighting enough away from the set ?

Is there short-circuit in the key input or

I

when the key is

YES

,

and signal

.

INFRARED WC

No operation is possible from the infrared remote control.

I

of the

pulse given out of pin (I)

YES

at pin

Check the switch contact.

NO

Check switches for poor soldering.

Check key lines to input of IClOOl.

I

NO

Reposition the set not to be

, I

Replace the infrared remote

control as required.

Check pin receiver.

exposed to strong light.

.

Check key input terminals.

I

FLOW CHART NO.

I

and

of IClOOl. and /or

and

lines.

I I

I

.

--- --- ----

TV TROUBLESHOOTING TABLE

I

NO RASTER

Normal

]

I I

I

,

I

FLOW CHART NO. 2-4

Replace the Fuse

I

Circuit to be checked:

TUNER

noise increases but no signal is received

Is there a signal at pin (8) of

gain

power source

I

Check

NO PICTURE, NO SOUND

I

Does the noise level increase at max,

Contrast, Brightness, and Sound Control ?

of

?

YES

and adjacent parts

h

FLOW CHART NO. 2-5

Is there a signal at

of

adjacent parts.

Check Tuner AGC.

YES

Check

--------

-----

-___

Check the IF Pack.

Check line.

NO VERTICAL SCAN

I

bias check.

Normal

I

FLOW CHART NO. 2-6

NO PLAYBACK SOUND

I

Check the TV: TROUBLE

SHOOTING ‘NO SOUND’.

I

FLOW CHART

Check the CRT connector

,

--

Check

adjacent parts.

check

Normal

and adjacent parts.

and

NO SOUND

NO

Does waveform appear at

pin(8)oflC302?

I

Check speaker.

NO PLAYBACK PICTURE

I

Abnormal

I

FLOW CHART

FLOW CHART NO. 2-6

Circuits to be checked:

and its Adjacent Circuit

Output

(PAL

Check adjacent circuits.

and its

I I

Check 0851 and its adjacent circuits.

Is the white balance

properly adjusted

Readjust the white balance.

Check Q853 and its

I

adjacent circuits.

I

FLOW CHART NO.

I I

I

OVERALL SCHEMATIC DIAGRAM

I

H

G

FULL

ERASE HEAD

F

AUDIO CONTROL HEAD

VIDEO HEAD

I76GE

VT-5128X

I

E

LOADING MOTOR

I GE

D

I

I-

‘I---

,-

I I

C

I I I

I

I I I

B

DRUM MOTOR DRIVER

DRUM MOTOR

I I24GE

r

AT sv

I I

I

A

I

1

I

2

3

I

4

5

I

6

I I

I

X

t

i

I

DEFLECTION YOKE

I

X

IN

I I

I I I I

I I

I

I I

I I I

I I I I

I I

WITH -

IONS

I

7

8

I

9

I

CHASSIS LAYOUT OF TV SECTION

H

I

PC

cl

G

El

II

cl

0

.

0

F

1

0

I

t

E

. - .

I

0 0

D

0

I

IF

0

1

0

1

VIDEO

C

AUDIO

OUT OUT

l

B

A

n

1

2

I

3

I

4

I

5

I

6

1 01r

0

cl

U

7

I

8

I

POWER

9

I

cl

I

BLOCK DIAGRAM OF TV SECTION

I

R-Y. B-Y. AMP.

--(H-SYNC

.

I

( H-SYNC/H-FLY IN

I

1

I

2

I

. .

I

3

I

4

I

5

I

6

I

VIDEO

AMP.

VIDEO SW.

AUDIO AMP.

I AUDIO AMP.

I

IF PACK

I

J

7

I

8

I

9

I

BLOCK DIAGRAM OF TV SECTION

I-

I

VIDEO OUTPUT

CUT OFF

POWER

I

RELAY SW. ON/OFF SW ON/OFF

ERROR DETECT

I I

PHOTO

I

COUPLER

POWER

I

1

I

2

I

3

4

I

5

I

6

VCR-KEY

POWER SW-R/C

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

POWER CONTROL

I

START

RECTIFIER

I

ERROR AMP.

LATCH.

I

------

I I

I

I I

I

I I

I

I I

1

I

7

I

8

I

9

I

DESCRIPTION OF TV SECTION

SCHEMATIC DIAGRAM

SAFETY NOTE:

DISCONNECT THE AC PLUG FROM THE AC OUTLET BEFORE

PARTS.

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 (

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

) ARE IMPORTANT

IS

CAUTION:

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

slight difference from yours.

NOTES:

The unit of resistance “ohm

=

ohms, M =

resistors are

watt, unless otherwise

noted.

The unit of capacitance

=

The values in parentheses are the ones in the

mode; the values without parentheses are

the ones in the

mode.

is omitted.

Meg ohm).

is omitted.

VOLTAGE MEASUREMENT CONDITIONS:

DC voltages are measured between points

indicated and chassis ground by

AC

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

Voltages are measured with

with

B&W or

WAVEFORM MEASUREMENT CONDITIONS:

87.5% modulated

is fed into tuner.

bar signal

SOLID STATE DEVICE BASE DIAGRAM

VIEW

1 3

1

0

0 0

BASE

L

COLLECTOR

C E

1

9

1

9

1 AC: l.OVp-p

0

DC : 5.0 V

0

6

AC :

DC:

0

2AC:

0

7

AC : 2.2 Vp-p

WAVEFORMS (VT-3428X)

0

3

DC

AC: 1.7Vp-p

:

V

0

DC :

8

AC

DC:V

V

:

0

4

AC: 1.7Vp-p

DC :

9 AC : 50 Vp-p

DC:

0

5AC:

DC

:

0

AC :

Vp-p

0

I

I I I I I

AC :

0

AC:

DC:

0

AC: DC:

0

AC: 8OVp-p

DC:

WAVEFORMS

28X)

AC :

0

1

Vp-p

DC : 5.0 V DC : 3.2 V

0

I

0

I I I I I

AC :

0

I I I-

Vp-p

2 AC: 1.3Vp-p

7

AC :

MODEL VT-3428X SCHEMATIC DIAGRAM: Mother Unit

TO PWB-E

I I I I I I

I

2

I

3

I

4

I

5

6

1

I

I I

PWB-E

ii i

I

MODEL

I-

H

F

SCHEMATIC DIAGRAM: CRT Socket,

E

POWER

D

TO

C

TO

MOTOR

“CR

3

I I

A

1

I

2

I

3

I

4

I

5

I

6

VCR-Key

and

Power SW, R/C Unit

NOTE:. I. THE UNIT’ OF RESISTOR

ALL RESISTORS ARE I/BWATT. UNLESS OTHERWISE NOTED. ALL CAPACITORS ARE

IO00 OHMS.

IS OMITTED

UNLESS OTHERWISE

TO PWB-A

-o--p7

--m-

I

8

I

9

I

MODEL VT-5128X SCHEMATIC DIAGRAM: Mother Unit

H

G

EEPROM

F

TO PWB-E

E

TO

D

C

r

B

A

I

2

I

3

4

I

5

I

t

6

1

PWB-E

7

I

8

I

9

I

MODEL

--

TO PWB-A

SCHEMATIC DIAGRAM: CRT Socket,

TO PWB-A

POWER

I

1 I

2

3

I

4

I

5

I

6

and

Power SW,

‘NOTE: I. THE UNIT OF RESISTOR

IO00 OHMS. ALL RtSISTORS ARE I/BWATT.UNLESS OTHERWISE NOTED. ALL CAPACITORS ARE

R/C Unit

OHM

IS OMITTED

UNLESS OTHERWISE

TO PWB-A

VCR-KEY

I OPWBFB732PEZZ

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

.

Infrared Remote Control Unit

1

I

2

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3

I

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5

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6

1

IF-Pack Unit

l

1

I

2

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3

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4

5

I

6

1

CHASSIS LAYOUT OF VCR SECTION

II

VIDEO OUT

PB CHROMA

P

GND

I

.

0

cl

i

J

I’

END SENSOR

SENSOR

I-----l

I

I BIAS(+)

I

I I

CASSETTE LED

cl

CAM SW A

T V REEL SENSOR

EC

I

START SENSOR

HEAD SWITCHING

I

ED

UP

VOLUME

A

NON

7

UP

I

CH

A

8

I

POWER

WAKE-VP

.I

I

9

TIMER

I

CHILD LOCK

I

BLOCK DIAGRAM OF VCR SECTION

H

OVERALL

DIAGRAM

G

F

------I

L--

IEC

E

VIDEO s1ouAL

D

a

3

a

I

*-

3

C

a

B

A

1

I

2

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3

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4

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5

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6

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9

I

BLOCK DIAGRAM OF VCR SECTION

SERVO PROCESS BLOCK DIAGRAM

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

I I

I

1

I

2

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3

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6

1

I

7

I

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9

I

1

BLOCK DIAGRAM OF VCR SECTION

--------

1

I

2

I

3

I

4

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5

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6

I

n

SAFETY DEVICE BLOCK DIAGRAM

a

I I

I

7

I

8

I

9

I

m

I

MAD

MAO

I

ERASE

PROCESS

0

‘CC

BIAS

+

,

AT SV

SYSTEM CONTROLLER

MANUAL SYSTEM IS

TV.

I 37PIN

FROM

COMPOSITE SYNC.

MC

FROM CAPSTAN MOTOR

FROM CTL HEAD

2

I

EC

V-SYNC.

SEPARATOR

CAP. SHAPER

4

-u-u-

AMP

CTL

3OHr

AUTO SYSTEM IS TRANSFERED

SYS-CON DATA TO TV.

GENERATOR

TO VIDEO AUDIO

LPfHl

AUTO SYSTEM SELECT

BLOCK

BLOCK DIAGRAM OF VCR SECTION

H

VIDEO SIGNAL FLOW BLOCK DIAGRAM

G

F

I

E

D

C

B

A

1

I

2

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3

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4

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5

I

6

7

I

8

I

9

I

DESCRIPTION OF VCR SECTION

SCHEMATIC DIAGRAM

SAFETY NOTES:

DISCONNECT THE AC PLUG FROM THE AC OUTLET

BEFORE REPLACING PARTS.

SEMICONDUCTOR HEAT SINKS SHOULD BE REGARDED

AS POTENTIAL SHOCK HAZARDS WHEN CHASSIS

OPERATING.

NOTES:

The unit of resistance “ohm M = 1 Meg ohm).

All resistors are watt, unless otherwise noted.

The unit of capacitance “F’is omitted The values in parentheses are the ones in the the values without parentheses are the ones in the mode.

VOLTAGE MEASUREMENT CONDITIONS:

DC voltages are measured between points indicated and chassis ground by VTVM, with supplied to unit and all controls are set to normal viewing picture unless otherwise noted.

Voltages are measured with

signal.

WAVEFORM MEASUREMENT CONDITIONS:

percent modulated colour bar signal is fed into

tuner.

CAUTION: This circuit diagram is original one.

a slight difference from yours,

is omitted

Therefore there may be

=

p =ppF).

B & W or

ohm,

mode;

WAVEFORMS

tovp-p

P In

Y/C

P In COMPOSITE SYNC.

SERVO

CAPSTAN FG

P In

V :

SERVO

P In

CHROMA

P In

AUDIO

DRUM FQ

V : P In

H/A H/A

P In

SERVO

.(REO)

IC3301

AUDIO AUDIO AUDIO

P In

SYSTEM CONTROLLER

CLOCK

Ii:

P In

V :

P In

SERVO SERVO

P In

--SCHEMATIC DIAGRAM: VCR Unit-l

H

G

F

TO SYSTEM CONTROL.SERVOWCRI

E

.

C

B

A

1

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2

3

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4

I

5

I

6

3

7

I

8

9

I

SCHEMATIC DIAGRAM: VCR Unit-2

JLOADING MOTOR

w3

I

2

I

3

VOLTAGE SW

I

4

I

5

LED TIMER CHILD

I

LED DRIVE

6

DRIVE

LEO DRIVl

CIRCUIT

.

I

7

I

8

I

9

I

PRINTED WIRING BOARD ASSEMBLIES

TV SECTION

H

G

F

8

I

2

I

3

I

4

I

5

I

6

I

1

Power SW, R/C Unit

(Wiring Side)

Unit (Wiring Side)

7

I

8

I

9

I

TV SECTION

H

G

F

E

Power Unit (Wiring

D

C

B

A

I

2

I

3

I

4

I

5

CRT Socket Unil

I

6

Side)

7

I

8

I

9

I