SHARP VT-3418X, VT-5118X Service Manual
SHARP CORPORATION
N.S.W. SEWVIGE
1
HUNTINGWOOD DE;/.
BLACKTOVVEil
N.S.W.
DEPT.
2148
W-341 8X
VT-5118X
SERVICE MANUAL
S94D8VT3418Xi
TV/VCR COMBINATION
i==T=D
TELEVIDEO
Chassis No. VP-
7
VT-341 8X
VT-341 8X
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.
FEATURE
n Full Auto Search Tuning System
n
On Screen Digital Channel/Sound Level/
Tuning Display, Control (Contrast,
Brightness, Tint, P-Tone) Symbol and Level
H
Blue Back Off Timer
n
40 Key, Wireless Remote Control Unit
n Channel Skip
H
Dew Warning Indicator
W DPSS
(Digital Program Search System)
VT-51
18X
Colour,
MODELS
H
High Speed Video Search System
l
PAUSECAM: 7 times
l
NTSC:
w
Quick Start Playback with Full Loading System
n
Still/Slow Function with Noiseless Frame Still
n
Digital Automatic Tracking Control
n
Automatic Playback Function
n
AHC
(Automatic Head Cleaning System)
VT-51
5
times(SP),
15 times
18X
(EP)
I
.
SPECIFICATIONS
l
IMPORTANT SERVICE NOTES
l
LOCATION OF USER’S CONTROL
.
DISASSEMBLY AND REASSEMBLY
. ADJUSTMENT OF THE
TV ELECTRICAL CIRCUITRY
.
FUNCTION OF MAJOR MECHANICAL PARTS
. ADJUSTMENT, REPLACEMENTAND
ASSEMBLY OF MECHANICAL UNITS
. ADJUSTMENT OF THE
VCR ELECTRICAL CIRCUITRY
. TROUBLESHOOTING
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CONTENTS
Page Page
l
2
3
4
7
8
14
..
16
41
47
OVERALL SCHEMATIC DIAGRAM
l
CHASSIS LAYOUT OF TV SECTION
l
BLOCK DIAGRAM OF TV SECTION
.
DESCRIPTION OF TV SECTION
SCHEMATIC DIAGRAM
.
CHASSIS LAYOUT OF VCR SECTION
.
BLOCK DIAGRAM OF VCR SECTION
. DESCRIPTION OF VCR SECTION
SCHEMATIC DIAGRAM
. PRINTED WIRING BOARD ASSEMBLIES . .
.
REPLACEMENT PARTS LIST
.
PACKING OFTHESET
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.......
.......
........:.....
......
.....
*
.............
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65
69
73
82
99
101
111
119
129
167
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
n
OUTLINE OF THE PRODUCT
Power Source:
Power Consumption:
Receiving Broadcast Standard:
Receiving Channel:
Receiving System:
Antenna Input Impedance:
Video Signal:
Audio Signal:
Temperature:
Di
mentions
n
TV SECTION
n
VCR SECTION
Weight (Approx.):
Cabinet Material:
(Approx.):
Accessories:
Viewing Area:
Picture Power:
Speaker Output:
Picture Tube:
SPECIFICATIONS
11 O-240
VT-3418X: 77
i/T-5118X: 98 W
PAL System B/G, I, D/K, M
VHF;
UHF;
Sound;
Colour;
VHF/UHF;
Input;
output;
Input;
output;
Operation;
Strege;
VT-3418X: 392
VT-5118X: 523mm(W)x488mm (H)x483
VT-3418X: 14.2
VT-5118X: 26.1
Plastic
0
Operation Manual
Cl
Infrared Remote Control Unit
0
Dry Batteries, Type AA (x 2
0
Guarantee Card
VT-3418X: 33.54
VT-51 18X: 50.8
VT-3418X: 22.0 kV
VT-5118X: 25.0 kV
VT-3418X: 1.5
VT-51 18X: 1.5
Type;
Heater;
Focus;
V AC,
VT-3418X: 6.3 V, 300
50/60
Hz
w
lA-S20
E21-US83
5.5/6.0/6.5/4.5
PAL /
SECAM / NTSC
75
ohm Unbalanced (DIN)
O-5-2.0
1 .O
-
-8db/lkohm(RCA)
VT-3418X:
VT-5118X: VB51JFCGlX/E2
VT-5118X: 6.3 V, 680
High
Vp-p / 75 ohm (RCA)
Vp-p /
8 d b /
47k
5”Cto40”C
- 20°C
to
mm
(W)
kg
kg
cm Diagonal Measurement
cm Diagonal Measurement
at
at
W at Max. (8 cm Round Dynamic x 2
W at Max. (8 cm Round Dynamic x 2
Bi-Potential Electrolstatic
MHz
75 ohm (RCA)
ohm (RCA)
60°C
x
371
mm
PCS)
800 ,&
1100 fi
VB370BVBKl
Beam Current
Beam Current
mA
mA
(H)
x
395
U-S (Tint Tube)
(TintTube)
mm
mm
(D)
(D)
PCS)
PCS)
Outline:
Format:
Video Recording System :
Luminance: FM Recording
Chrominance: Low Frequency Converted Direct Recording
Video Signal System: PAUSECAM/NTSC 3.58
Cassette Tape:
Tape Width:
Tape Speed:
Recording/Playback Time:
Note: The antenna must correspond to the new standard DIN 45325
antenna with 75 ohm connector.
VHS
Video System
VHS PAUNTSC
Rotary Slant Azimuth 2-Head Helical Scan System
VHS
Type Video Cassette Tape
12.7
mm
PAL;
NTSC;
SP;
LP;
EP;
23.39
mm/s
33.35 mm/s
Max.
240 min
Max.
480 min
Max.
480 min
Colour
Standard
MHz
(SP), 11.70
(SP),
(with
(with
(with
Video Cassette Recorder
Colour
mm/s
11.68 mm/s
E-240)
E-240,
T-160, NTSC
(LP)
(LP*PB
PAL only)
only)
only), 11
(IEC 169-2)
-12
mm/s
(EP)
for combined UHF
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-3418X:
VT-5118X:
2. VT-3418X:
VT-5118X:
-‘.
If there is a possibility that the high voltage fluctuates as a result of the repairs, never
forget to check for such high voltage after the work.
3.
DO not substitute a picture tube with unauthorized types and/or brands
excess X-ray radiation.
When repairing the circuit, be sure not toincrease the high voltage to more
than
25.3 kV,
When repairing the circuit, be sure not to increase the high voltage to more
than
29.3 kV,
To keep the set in a normal operation, be sure to make it function on
22.0 kV
been factory
To keep the set in a normal operation,
25.0 kV + 1.5 kV
factory -Adjusted to the above-mentioned high voltage.
(at beam 0 +) for the set.
(at beam 0 +) for the set.
+
1.5 kV - 2.0 kV
-Adjusted to the above-mentioned high voltage.
(at beam
(at beam
1100 ,uA)
800 ,&)
in the case of the set. The set has been
in the case of the set. The set has
be sure to make it function on
which may cause
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 resistorcapacity networks, mechanical insulators etc.
LOCATION OF USER’S CONTROL
CONTROL PANEL
INSIDE THE COVER
POWER BUTTON
\
VlDEO INPUT JACK
AUDIO INPUT JACK
I
VIDEO AUDIO
STOP/EJECT BUlTON
PLAY BlJlTON
FF
(Forward video search)
BUTTON
mh
I
;;;rF$verse
VOLUME UP/DOWN
CHANNEL UP/DOWN
r
video search)
BlJlTONS
BUlTONS
I
SENSOR AREA FOR
REMOTE CONTROL
VT-341 8X
o I
I
p
MAIN POWER SWITCH (0 I)
q
POWER CORD
ANTENNA IN TERMINAL
AUDIO OUT TERMINAL
VIDE;
OUT TERMINAL
I
o
. . .
v
JL
_1
-
VT-51
18X
MAIN POWER SWITCH (0
ANTENNA IN TERMINAL
AUDIO OUT TERMINAL
VIDEO OUT TERMINAL
4
.
P;;WER
I)
CORD
I
-
-
Remote Control Battery Installation
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
buttons.
Inserting the Batteries
The remote control operates on two R6 (UM/SUM-3,
AA)
1.5
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.
Open the battery cover. (Remove any old bat-
Battery
cover
0
teries that may be in the remote control.)
Insert new batteries and match their polarities
@
( + and -) with the markings inside the compartment.
@
Replace the cover.
Location
POWER ON/OFF button (0
EJECT/LOAD button
CHANNEL SELECT
buttons
DISPLAY button
DPSS(O, @)I
SLOW@, 0) buttons
SP/LP*EP
REC
button
REW/Reverse -
Video Search button
TIMER ON/OFF button
CONFIRMING TIMER
PROGRAMME button
of Controls
I)
button
-
-
666
--686
SHARP
VIDEO
-TV
C-COCK
r
I
I
/--
MUTE button
CHILD-LOCK button
r
1
r
r
-
CHANNEL UP/DOWN&&tons
(TRACKING buttons)
VOLUME ADJUSTMENT
buttons
SLOW PLAYBACK button
COUNTER RESET button
STOP button
F*ADV
button
-
PAUSE/STILL button
FF/Forward
Video Search button
PLAY button
-,
+ buttons
PROGRAMME button
MENU button
SET button
5
c
VT-341
8X
VT-5118X
n
TV SECTION
DISASSEMBLY AND REASSEMBLY
I. VT-3418X:
VT-51
18X: Remove the nine screws off the rear cover.
Disconnect the F and G connectors from the main
2.
3.
Remove the screws off the video unit and take out the unit.
4.
Remove the two screws from the main
VT-341
Remove the eight screws off the rear cover.
PWB.
PWB
and separate the
8X
rr
PWB
from the video unit
VT-51 18X
6
n
CONNECTIONS FOR SERVICING
Use the following extension cables in servicing the VCR unit taken out of the set.
Extension cables:
l
Connecting the extension cables
(1)
Between AB (TV unit) and JA
Connect the cable
(2)
Between AL (TV unit) and LA (LED unit):
Connect the cable
Part codes
QCNW-3778CEZZ
QCNW-3780CEZZ
QCNW-3778CEZZ, QCNW-3780CEZZ
(AV
jack):
between the AB plug and the AB socket.
between the AL plug and the AL socket.
Extension cable: QCNW-3780CEZZ
Extension
5.
6.
cable: QCNW-3778CEZZ
Remove the CRT
the main
PWB
PWB, degaussing
upright.
Reconnect the CRT
PWB.
power switch remote control
*
VT-51 18X
Only for
~oUnd0
coil connector G, and front power switch remote control
Put the main
PWB,
speakers and
PWB.
PWB
and the VCR unit together as shown below. Keep the front
degaussing
coil connector G off position.
Place
(Only for VT-341 8X)
Power
SW+I/C
/
PWB
DA
\
‘LINE FILTER PWB
,
VT-341
8X
VT-5118X
I
I
ADJUSTMENT
TV ELECTRICAL CIRCUITRY
VIDEOKHROMA
I
1.
CRT Cut-off Adjustment
Adjusting Point
Cl
R853:
Cl
R859:
Cl R865:
El T602: Screen control (a pat-t of T602)
Cl R857:
!Il
R863:
Note:
Prior to this adjustment, warm up the unit with the
beam current of more than
7004 (VT-51 18X)
1.
Receive “MONOSCOPE PATTERN” signal with
pattern generator.
2.
Set Red bias control at
Set Green bias control at
Set Blue bias control at
Set Green drive control at CENTER
Set Blue drive control at CENTER
3.
Set the control at the “NORMAL” position that
Contrast is MAX
Brightness is CENTER
“v”
keys.
4.
Set the Screen control at
5.
Turn on
line position.
6.
Connect the oscilloscope to
Adjusting Conditions
Red Bias control
Green Bias control
Blue Bias control
Green Drive control
Blue Drive control
for more than 30 minutes.
MIN
(O/l 0) position.
MIN
MIN
(O/l 0) position.
(60), Colour
(0)
using control, “A” and
MIN
51401
(Service switch) at the horizontal
6OOfl (VT-3418X)
(O/l 0) position.
(5/l 0)
position.
(5/l 0)
position.
is CENTER
(O/l 0) position.
TP852
(Red Cathode).
(0)
OFTHE
ADJUSTMENT
1.
Adjust the Sub-Brightness control
the blanking pulse on oscilloscope is 10 +
2.
Slowly turn the Screen control clockwise and stop
I
an
it where the horizontal raster appears slightly, in
one of the three
3.
Carefully adjust the Bias controls of the other two
colours
4.
Turn the Screen control counterclockwise until
the horizontal raster disappears, and stop it.
untii the horizontal raster becomes white.
Adjusting Procedures
colours.
(R425)
so that
lVp-p.
2.
Sub-Contrast Adjustment
Adjusting Point
I
0 R421:
Sub-Contrast control
I
Note:
Prior to this adjustment, warm up the unit with the
beam current of more than
7004 (W-51 18X)
1.
Receive “MONOSCOPE PATTERN” signal with
pattern generator.
2.
Set the Contrast and Brightness controls at MAX
position.
3.
Connect DC
TP602@.
(Full scale: 3
for more than 30 minutes.
milliammeter
mA)
600@ (VT-3418X)
to
TP6019
and
1.
Adjust Sub-Contrast control so that the beam
current becomes
5118X).
I
0.8
mA
(VT-3418X) /
8
1 .l mA
(VT-
VT-341
8X
W-5118X
VIDEOICHROMA
3.
White Balance and Back Ground Adjustment
Adjusting Point
El R857:
Cl
Cl R421:
Vote:
srior
5eam
7004 (VT-51 18X)
I. Receive “MONOSCOPE PATTERN” signal with
pattern generator.
!.
Set the Contrast and Brightness controls at MAX
position.
5.
Connect beam ammeter to
(Full scale: 3 mA)
Green Drive control
R863:
to this adjustment, warm up the unit with the
current of more than
Blue Drive control
Sub-Contrast control
6004
for more than 30 minutes.
TP601
(VT-3418X) I
and
TP602.
ADJUSTMENT (Continued)
1.
Adjust the Sub-Contrast control so that the beam
current becomes
5118X) (rough adjustment).
2.
Adjust the Green Drive control and Blue Drive
control so that the colour temperature is at
10900K.
l
High beam:
0.8
mA
1.1
mA(VT-5118X)
3.
Adjust the Contrast control and Brightness
control so that the beam current is
200,&,
at
9300°K.
go back to “CRT CUT-OFF ADJUSTMENT” and
repeat the adjustment.
(X = 0.285,
0.8
mA
(VT-3418X) /
(VT-341 8X)
and check that the
If the temperature is not at
Y = 0.292)
colour
1 .l mA
temperature is
(VT-
approx.
9300”K,
4.
Sub-Tint Adjustment
Adjusting Point
0 R1882:
1.
Feed
with
2.
Connect oscilloscope to
3.
Set the Tint control at the CENTER
4.
Set Service switch
to cut off the Y-signal.
1
j.
Bell Filter Adjustment
Adjusting Point
0 T1802:
1.
Receive
bar generator.
2.
Connect oscilloscope to TP1801 with the
following settings.
l
Range:
l
Sweep Time:
l
Probe:
Sub-Tint control
“NTSC
COLOUR BAR” signal to video in jack
colour
bar generator at the AV mode.
TP853 (B - Y).
51401
at the Video Cut position
Bell Filter
“SECAM
COLOUR BAR” signal with colour
0.05V /
20psec /
l/l 0
div. AC
div.
(3OpF,
1
OMQ
(0)
position.
or more)
1.
Adjust
approx. 3Vp-p.
2.
Adjust Sub-Tint control
waveform is as shown in figure below.
3.
Return
1.
Adjust the Bell Filter
output and blue
amplitude.
Colour
51401
Same
B-Y
CY G Mg
control key to obtain the output of
(R1882)
to CENTER (normal position).
level
y
/’
/-
.)
.
W Y Cy
-
(B)
R
B
‘c_
/@(
-
GMg
(T1802)
output will have the same
Same amplitude
so that the output
_.z_‘-
-
-
R B
so that the red
//-
(R)
r-
9
VIDEOICHROMA
ADJUSTMENT (Continued)
Adjusting Conditions
6.
PAL
Adjusting Point
Cl
0 T1801:
Note: Before this adjustment, the
1.
Receive “PAL COLOUR BAR” signal with pattern
generator.
2.
Connect the following resistance matrix to pins 3
and 4 of the connector
oscilloscope is connected.
TP853 (K)+
3.
Set the Service switch
position to cut off the Y-signal.
Chroma
R1806:
adjustment must have been completed.
Adjustment
1 H Delay Amp. control
1 H Delay Phase control
(K),
to which an
22 kSZ
To oscilloscope
Resistance Matrix
51401
at the Video Cut
PIFIAFTIAGC
I
1.
Adjust the
waveform of
1.5
vp-p.
2.
Adjust
waveform shown in Fig. a is corrected to that
shown in Fig.
3.
Return
Adjusting Procedures
Colour
control key so that the output
colour
difference signal becomes
R1806
and
T1801
so that the output
6.
51401
to CENTER (normal position).
W Y Cy G Mg R B
--#--.
-
-
u
--*m---w
.-
---m-
r
-
mm --m-w
1
Figure a. Waveform before the adjustment
1
1.5 vp-p
I
7. SECAM
r
Adjusting Point
0 11803:
1. Receive”SECAM
bar generator.
2.
Connect oscilloscope to
following settings.
l
Renge:
l
Sweep Time:
Killer Adjustment
SECAM Killer
COLOUR BAR” signal with
lV/div.
(Adjust vertical position proper
20psec /
DC
div.
control
TP1802
colour
with the
,lY.)
IO
Figure 6. Waveform after the adjustment
1.
Adjust
TPl802
T1803
to obtain maximum DC voltage at
(approx. 9.5V).
VIDEOKHROMA
Adjusting Conditions Adjusting Procedures
8.
R -Y/B -Y Discriminator Adjustment
Adjusting Point
0 T1804:
0 T1805:
1.
Receive “SECAM COLOUR BAR” signal with colour
bar generator.
2.
Connect the oscilloscope (with two
TP851 (R - Y)
on the CRT Socket Unit of the set.
l
Renge:
l
Sweep Time:
3.
Set service switch
’
to cut-off the Y-signal.
4.
Set both the Contrast and Brightness controls to
their maximum postions.
R - Y Discriminator
B - Y Discriminator
and the
TP853 (B - Y),
lV/div.
20psec /
51401
DC
div.
at the Video Cut position
channecls)
both located
ADJUSTMENT (Continued)
to
1.
Adjust
output level with
will be the same as that with
100%
* Connect capacitor (0.001
2.
Set service switch
T1804 (R - Y)
of saturation. (A =
TP853,
thus to prevent noise interference.
and
colour
51401
TP851
T1805 (B - Y)
control set at minimum
colour
B)
,xF)
to the canter position.
so that DC
control set at
to
TP851
and
TP853
*
Same
B
DC
DC output level
OV
11
VT-341 8X
VT-5118X
DEFLECTION LOOP ADJUSTMENT
Adjusting Conditions
1.
Focus Adjustment
Adjusting Point
0 T602: Focuscontrol (a part of
1.
Receive “MONOSCOPE PATTERN” signal.
2 Set the Brightness and Contrast controls at
NORMAL position.
2.
Horizontal Center Adjustment
Adjusting Point
Cl
RI
602: Horizontal Center control
Note: This adjustment should be performed after
the purity and convergence adjustments.
1.
Receive “MONOSCOPE PATTERN” signal.
T602)
Adjusting Procedures
l
During the adjustment, keep the unit facing the east.
1.
Adjust Focus control (a part of
focus at the central area of CRT.
l
During the adjustment, keep the unit facing the east.
1.
Adjust
picture is at the position which gives the relation
ofA=B.
R1602
so that the horizontal center of
+
I
A-
l
T602)
Adjust point
-)B
to have best
4
3.
Vertical Linearity Adjustment
Adjusting Point
Cl R526:
1.
Receive “MONOSCOPE PATTERN” signal.
4.
Vertical Size Adjustment
Adjusting Point
Cl R503:
1.
Receive “MONOSCOPE PATTERN” signal.
2.
Set the Brightness and Contrast controls at MAX
position.
Vertical Linearity control
Vertical Size control
(+=
I
I
l
During the adjustment, keep the unit facing the east.
1.
Adjust
picture is at best point.
l
During the adjustment, keep the unit facing the east.
1.
Adjust
the same size as horizontal size.
. V-SIZE
R526
so that the vertical linearity of
R503
so that the vertical size of picture is at
8%
TYP
12% MAX
12
DEFLECTION LOOP ADJUSTMENT (Continued)
VT-341 8X
VT-5118X
Adjusting Conditions
5.
Vertical Centering Adjustment
Vertical Center Adjust switch
This adjustment should be performed after
the purity and convergence adjustments.
“MONOSCOPE PATTERN” signal.
ADJUSTMENT OF THE IF CIRCUIT
Adjustment of the RF
Test point
Adjusting point
TP201 @I (GND)
TP201 0
VROOl (AGC
I
AGC
(Video Output)
control)
Adjusting Procedures
l
During
the’adjustment,
1.
Adjust
idential to CRT geometrical vertical center.
5501
so that the picture’s vertical center is
keep the unit facing the east.
Adjustment of the AFT
Measuring
instrument Signal generator
Mode
Input signal
Test point
I
Adjusting point
Oscilloscope
EE
I
PIF
frequency
Colour bar signal
TP201 @ (GND)
TP201 @
I
TOO2
I
(Video Output)
(AFT coil)
uniwave
(70
dBp)
1.
Receive the
strength: 80
2.
Observe the video output terminal waveform
on the oscilloscope. Adjust
in the IF pack until the noise disappears from
the oscilloscope screen and the waveform
nearly comes into sync.
Just before shrinking
colour
dBp).
bar signal (input field
Figure
VROOl (AGC
1.
control)
Specification
1.
Receive the colour bar signal (input field
strength: 70
2.
Using the signal generator, feed the
frequency
tuner IF output terminal.
3.
Set the tuning switch to the VHF or UHF
position. Keep the tuning button
depressed until the beating on the oscilloscope
screen be minimum.
4.
Set the tuning switch on the normal position.
Adjust
oscilloscope screen be minimum.
TOO2
-
I
dBp).
(38.9
MHz) signal (sinewave) to the
(+)
or
(AFT coil) so that beating on the
PIF
(-)
13
I
Figure 2. IF Pack
FUNCTION OF MAJOR
Take-up pole
Drum
Full erase head
Supply pole base
Tension arm
MECHANICAL PARTS
base
ass’y 2
ass’y
ass’y
I
ass’y
ass’y
Brake shifter w
I
Q,
\
24 AHC(Automatic
0
@/Cheadass’y
/
Head Cleaner)
(TOPVIEW)
@Camztch
h
Ass’y
23
Dew sensor
AJ
Loading motor
Master cam
Pinch roller lever
Relay shifter lever
Capstan D. D. motor
Reverse guide
Take-up reel disk
Video
lever
ass’y
search brake
Back tension lever
Main supply brake
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.
4.
Brake shifter
,Set the position of brake or the like in accordance with
the modes such as stop and playback.
5.
Back tension lever
Brakes the supply reel disk to a certain degree to .
’
prevent tape slackening during “half-loading”,
“loading” and “shifting from playback to video search
rewind”.
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.
ass’y
Function
ass’y
No.
Reverse guide
13.
Pulls out the tape in the video search rewind mode,
and controls the tape drive train height with the upper
and lower guides.
Relay shifter lever
T5.
Transmits the operation of the master cam to the
brake shifter, and operates the reverse guide.
Pinch roller lever
16.
Press-fits the 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 the tape.
Master cam
17.
Turns clockwise during loading, and counterclockwise
during unloading, and moves the shifter or the like in
accordance with each mode.
Loading motor
18.
A motive power which drives the mechanism. It
transmits the power to the master cam and cassette
housing control assembly via the belt.
Function
ass’y
9.
Main take-up brake lever
Brakes the take-up reel disk to prevent tape slackening Rotates synchronously with the master cam, and
when the unit is stopped in fast forward or rewind detects the position of each mode by means of the
mode.
11.
Video search brake lever
It is in contact with the take-up reel disk normally, and
brakes it to a certain degree. It applies larger brake in unit. This element is activated, when it senses
the video search rewind mode.
Cam switch
19.
internal switch.
Dew sensor
23.
An element which detects condensation inside the
condensation, to interrupt the mechanism.
14
FUNCTION OF MAJOR
MECHANICAL PARTS
Slow brake lever
Loading relay gear
Capstan D. D. motor
Reel belt
Relay gear drive lever
I
x
3
o=
@-
(BOmOM
VIEW)
IO
Supply loading gear
/o
Reel sensor
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.
Brake solenoid
5.
Adsorbs and holds the brake shifter in the fast forward
and rewind modes, and releases it in the stop mode.
Reel pulley
6.
Transmits the power of the capstan
reel disk via the reel idler.
D-D.
7
d
motor
Brake
Function
solenoide
D.D.
motor linking to
D.D.
5
()
motor to the
d
Reel pulley
No.
7.
9.
10.
.
11.
Function
Reel sensor
An element which sheds the light onto the reflection
plate affixed to the bottom side of the reel disk, and
detects the rotation of the reel disk through receiving
the reflected light.
Take-up loading gear
Shifts the take-up pole base and guide roller via the
loading relay gear, and applies the tape around the
durm
assembly, as well as transmits the power to the
supply loading gear.
Supply loading gear
Shifts the supply pole base and guide roller via the
take-up loading gear, and applies the tape around the
drum assembly.
Relay gear drive lever
Transmits the movement of the master cam to the
take-up loading gear via the loading relay gear.
15
ADJUSTMENT, REPLACEMENTAND
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).
TOOLS NECESSARY FOR ADJUSTING THE MECHANICAL UNITS
The following tools are required for proper service and satisfactory repair.
These Jigs are used for checking and
adjusting the reel disk height
A/C Head Tilt Adjusting Jig
6
Cassette Torque Meter
Tension Gauge (3009) .
7
Tension Gauge
Hex Wrench (0.9mm)’
Hex Wrench (1.2mm)
8
Hex Wrench (1.5mm)
Alignment Tape (PAL)
9
Alignment Tape
JiGVHT-063
JiGSG0300
(2.Okg) JiGSG2000
JiGHW0009 AE
JiGHW0012
JiGHW0015
VROCPSV
(NTSC)
VROATSV
VRONBZGS
CZ
BF
BS.
AE
AE
11
w
<
f4sz$zg
These Jigs are used for checking and
for checking and adjusting the
torque of take-up for measuring
There are two gauges used for the
tension measurements, 300 g and
2.0
kg.
These Jigs are used for loosening or
tightening special hexagon type
screws.
This tape is especially used for
electrical fine adjustment.
10
Drum Replacing Jig
JiGDT-0001
BG
This is used for replacement of the
VCR’s upper drum.
16
No.
11
Tension Gauge Adapter
Jig Item
Part No.
JiGADP003
Code
BK
Configuration
ecih
Remarks
This Jig is used with the tension
gauge. Rotary transformer
clearance adjusting jig.
Special Bladed Screwdriver
12
Tension Band and Plate
13
Adjusting Jig
14
Torque Driver JiGTDl200
Box Driver
15
Reverse Guide Height Adjusting
16
Jig
JiGDRiVERH-4 AP
JiGDRiVER-
JiGDRiVER
JiGDRiVER
JIGRVGH-F18 BU
1
10-7
O-4
BM
CB
AS
AV
This screwdriver is used for adjusting
the guide roller height.
This Jig is used for adjusting the
tension band and tension plate.
This is used to screw down resin-
made parts: the specified torque is 5
kg-
This Jig is used for height
adjustment of the A/C head and X-
position.
0
&@
This Jig is used for height
adjustment of the retaining guide.
This Jig is used for height
adjustment of the reverse guide.
17
MECHANICAL PARTS REQUIRING PERIODICAL INSPECTION
Use
the
following
table as a guide to maintain the mechanical parts in good operating condition.
;uide
roller
ass’y
;upply
impedance roller
;upply
impedance roller
)nner
hole and shaft)
;upply
impedance roller flange
Retaining guide
slant
pole
Video head (upper drum
Full-erase head
AIC
head
Lower drum
Capstan
Pinch roller
D.D.
ass’y
Motor
ass’y)
1000 1500 2000
Cl
q 0 0
0
0 q 0
q
q q q q
q 0 q q
q q q 0
q
00
q
0 Cl
q 0 q
cl
q q
cl cl q 0
q cl q 0
q Cl q 0
Possible symptom encountered Remarks
Abnormal rotation or
significant vibration
requires replacement.
q
Lateral noises
. Head occasionally blocked
Poor S/N ratio, no color
0
Poor colour, beating
0
Sound too small or distorted
Poor flatness of the envelope with
alignment tape
No tape running, uneven color
No tape running, tape slack
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.
Reel belt
Loading belt
Cassette loading belt
Tension band
Loading Motor 0
AHC
(Automatic Head Cleaner)
Reel block*
* See the table below for servicing the reel block parts.
SupplyTTake-up reel disks
Video search brake lever
Idler gear
Reel Pulley
ass’y
ass’y
cl
q
cl 0
0 0
IJA
CIA
A 0 No tape running, tape slack
No tape running, tape slack, no
0
fast forward/rewind motion
0
Cassette not loaded or unloaded
Lateral image swing
0
Cassette not loaded or unloaded
See the chart below.
0
No tape running
0
00
Clean rubber and rubber
contact area with the
specified cleaning liquid.
Replace the roller of the
cleaner when it wears
down. Just change the
AHC
roller assembly for
new one.
Clean with pure high
quality isopropyl alcohol.
Main
supplyfiake-up
NOTE:
brake levers
0:
Part replacement.
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
1000 hrs).
If the reading is out of the specified value, clean or replace the
18
par-t.
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 loading belt
b)
Disconnect the
c)
Remove the cassette housing installation
screws
d)
Slide and pull out the cassette housing control
assembly @ upward.
0.
FFC
(Full Flat Cable)
w
49
4
n
0.
a.
When the
detached, tuck it
as in the figure so
that it is kept free
from grease.
ble)
loading Note the
belt is
4.
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.
5.
Place the unit in the eject mode in removal or
reassembly of the cassette housing control
assembly.
6.
Load the cassette once onto the cassette housing
control assembly after reassembly. (If the
cassette housing control assembly normally
operates after this, the phases of mechanism and
the cassette controller are accurately adjusted
after ej
ecti
on.)
MECHANICAL OPERATION CHECK
WITHOUT
When power is on, the general operations of the
mechanism can be checked without a cassette.
Check video search rewind and rewind, rotating
the take-up reel disk @ by hand (in either
normal or reverse direction). If it is not rotated,
the reel sensor works to shift the mechanism to
the eject mode.
When the stop button is pressed, the mechanism
does not stop at a normal stop position. It shifts
to the eject mode and stops.
When the stop button is pressed in the playback,
video search rewind, and video search forward
modes, the supply reel disk 8 keeps on rotating
for several seconds for elimination of tape slack
in the course of shifting to the eject mode. In
such a case, rotate the take-up reel disk
somewhat by hand, and the supply reel disk
stops, which can reduce the working time.
CASSElTE
following points.
@
@
insert the tab of
the Cassette housing
Figure1 -1.
Reassembly
.
Before installation of the cassette housing
control assembly, place the unit in the stop mode
with the power on, then unplug the power cord.
(The main body is placed in the eject mode.)
&.
Follow the procedures for removal in the reverse
order.
Notes:
1.
Be sure to unplug the power cord in removal and
reassem blv.
2.
Keep the cassette loading belt free from grease.
In case of its adhesion, clean the belt.
3.
In using a magnet screw driver, be sure to keep it
away from the A/C head, FE (Full Erase) head, or
the drum.
control assembly to
the mechanism chassis.
REPLACEMENT OF WORM WHEEL
ASSEMBLY
Cassette housing frame
FO
/
Figure
Worm wheel
l-2.
Cassette switch
Worm bracket
tight screw
ass’y
19
VT-341
W-51
18X
8X
l
Removal
1.
Unsolder the cassette switch connectors (No.
17)
from the start sensor
Cassette switch
connector
2.
Lift the start sensor
sensor
PWB
fixing hooks inward.
PWB.
Start sensor
Figure
l-3.
PWB
pressing the two start
Start sensor
PWB
PWB
16,
5.6Place the slider pin just above the worm wheel
assembly (Figure l-7). (The retainer of the slider
is locked at two positions. So unlock it as in the
Figure
1-8.)
Pull out the worm wheel assembly toward you
pressing the switch lever upward. (Figure
Phase
ge
shaft
Tally mark
‘%ut
washer
Figure
l-7.
l-7)
itch lever
Figure
l-4.
3.
Unscrew one B tight screw to detach the worm
bracket.
Note:
The worm shaft bearing can easily come-out of
position. So be careful not to lose it.
-Worm bracket
LWorm
4.
Remove the worm shaft assembly, pulley, and
Figure
wheel
l-5.
ass’y
cassette loading belt all from the cassette
housing frame
Worm shaft a
(R).
Cassette housing
frame
(R)
the
(L)side
/-Slider
Cassette housing frame
(R)/(L) side
Figure
l-8.
Reassembly
Turn the phase gear clockwise until the slider
comes to a halt in the cassette insertion
direction. (See the Figure
l-9.)
Insert the set up worm wheel gear assembly into
the cassette housing frame
(R),
matching the
mark on the phase gear with the mark on the
worm wheel gear. Detach the cut washer on the
phase gear assembly and the phase gear for
easier installation of worm wheel assembly.
Note:
Make sure that the slider pin is in the groove of
the drive gear arm.
Figure
l-6.
20
Xut
Phase
/
washer
wheel
arm
VT-341 8X
VT-5118X
Tighten one B tight screw.
Note:
Do not over-tighten the B tight screw (no more
than
5.0 +, 0.5
of the screw hole at the resin-made boss can be
broken.
Place the start sensor
housing frame
Note:
Check that the switch connectors (No.
in the cassette switch mounting hole.
Finally resolder the cassette switch connector to
the start sensor
kg-cm), because the lower threads
PWB
on the cassette
(R).
16, 17)
are
PWB.
(a)
Install the pulley and the cassette loading belt on
3.
Figure
l-9.
b)
the worm shaft assembly. Couple the clutch to
the clutch lever. And mount them together in
the cassette housing frame
(R).
Note:
Keep in mind that the clutch switching lever
should be in the correct position.
mechanism might malfunction if the lever is
slightly out of position. (See page
Cassette housing frame
Worm wheel
ass’y
(R)
22.)
Cassette loading belt
The
k
-Cassette
housing
frame(R)
shaft bear
REASSEMBLY OF DRIVE GEAR
rPillar
Drive gear spring
Drive gear arm
ing
(R
,,
1
Drive gear arm
(4
Drive gear
spring
(R)
0
Worm wheel
square hole
I
LReciprocating spring
Figure
l-1 0.
4.
Attach the worm bracket to the worm shaft
assembly. Place them onto the boss on the
cassette housing frame
Note:
Insert 0 before screwing into Q and
Figure l-l
(R).
1
Cassette housing frame
P
r-3
1.
0.
(R)
21
spring-shaft
gear arm
(Drive gear bottom view)
(W
Figure
l-1 2.
1.
Pass the tip of the drive gear spring
(R) 0
through the square hole of the drive gear
hook the spring in position.
Hook one end Q of the reciprocating spring to
the catch of the drive gear
(R).
Hook the other end 0 of the reciprocating
spring to the catch of the worm wheel.
Insert the pillar @ of the drive gear
(R)
into the
square hole of the worm wheel. Turn the worm
wheel somewhat counterclockwise for insertion
of the worm wheel to the drive gear
(R),
because
the reciprocating spring is at work.
(R)
to
VT-341
8X
W-5118X
REPLACEMENT OF CASSETTE LOADING
BELT
Cassette
1.
Remove the start sensor
2.
Remove the worm shaft assembly
3.
Replace the cassette loading belt @ with a new
Notes:
1.
2.
3.
housing frame
bracket 0 from the cassette housing frame
(R)
Figure
l-1 3.
PWB @
Worm bracket
and worm
(R).
0.
one.
Do not over-tighten the B tight screw which holds
the worm bracket in position. The specified
torque is
5.0 2
0.5
kgcm.
Make sure that the cassette loading belt is free
from grease.
If stained with grease, clean the
belt with the cleaning liquid.
Perform checking of the clutch switch lever for
proper action.
CHECKING THE CLUTCH SWITCH LEVER
l
Checking
Place the mechanism in the cassette eject mode
when removing and attaching the cassette
housing from and to the mechanism chassis.
Make sure enough that each part in the cassette
housing such as the clutch switch lever is in
position. If not, it causes malfunction.
Note:
Figure
the cassette eject mode.
l-14
shows the position of each part in
Figure l-l
4.
1.
First make sure that the tip of the switch lever is
held at the rib of the drive gear
2.
Check that the rib of the cassette housing frame
(R)
and the concavity of the clutch lock lever are
(R).
engaged.
Finally be sure that the relationship between the
3.
clutch lever and the clutch, as well as between
the clutch and the pulley, are correct as in the
Figure l-1
5.
.
Check that the clutch is engaged
with the pulley through the coupling.
0
Resetting
Figure l-l
5.
Take the following steps to reset the clutch if it is
unlocked or if the switch lever and the clutch
lock lever are unlocked.
LDrive
gear
Shift the slider by turning the coupling in the
1.
(R)
lever
LClutch
l-1
lock lever
6.
Rib of cassette housing frame
Figure
arrow direction (clockwise) until the slider pin is
at the bottom of the slider groove as shown in
the Figure l-16. (The loading mode)
Note:
Note that the slider is
mechanism.
housing frames
Unlock the locks on cassette
(L)
equipped’with
and
(R)
a lock
side before shifting
the slider.
When the position is set as shown in the Figure 4-
16, push the clutch release lever in the direction
of the arrow by hand until the clutch lock lever
becomes tightly locked by the rib of the cassette
housing frame
(R).
Then turn the coupling counterclockwise until
the slider reaches the cassette insertion opening
and the reciprocating spring is activated.
Note:
There is no need to unlock the slider when
shifting the slider to the cassette insertion
opening. Just keep shifting the slider.
lever
(R)
22
REPLACEMENT OF LOCK RELEASE LEVER
l
Removal
1.
Place the slider in the cassette down position.
(Turn the coupling on the worm shaft clockwise
until the slider is in the cassette down position.)
Note:
Before shifting, unlock the slider.
2.
Slightly widen the cassette housing frames
and
(L)
to unhook the slider holders
(R)
and
the slider assembly off the grooves of the
cassette housing frames.
Pulley
(L)
(R)
of
VT-341 8X
VT-5118X
4.
Remove the lock release lever from the slider
holder(R)
l
Reassembly
1.
Follow the steps for removal in the reverse order.
(See Figures
2.
Attach the lock release lever to the slider holder
00.
3.
Slide the slider holder
two catches of the slider holder
opening of the slider.
4.
Slightly widen the cassette housing frames, and
set the pins of slider holders
grooves of the cassette housing frames.
Note:
Check if the pins of the slider holders
fit the grooves of the cassette housing frames,
and if the drive gear arm is sufficiently engaged
with the slider holders.
5.
Turn the coupling counterclockwise until the
slider is at the cassette insertion opening.
l-17
and
l-18.)
(R)
downward so that the
(R)
(R)
and
(L)
(R)
fit the
into the
and
(L)
(4
(b)
3.
Lift the slider holder
Figure l-l
7.
(R)
upward about
2mm
the slider by pressing two catches with a thin tip
screw driver.
catches.
Take care not to damage the
/-Slide
off
lock catch
TO RUN A TAPE WITHOUT THE CASSETTE
HOUSING CONTROL ASSEMBLY
1.
Plug in the power cord.
2.
Turn on the power switch.
3.
Open the lid @ of a cassette tape by hand.
4.
Hold the lid with two pieces of vinyl tape
5
Ined. We
0.) 7-
Set the cassette tape in the mechanism chassis.
6.
Stabilize the cassette tape with a weight @ to
prevent floating.
Perform running test.
Q.
Figure
l-1 8.
Note:
The weight should not be more than
Figure
l-1 9.
23
500 g.
REPLACEMENT AND HEIGHT CHECKING
AND ADJUSTMENT OF REEL DISKS
Remove the cassette housing control assembly.
1.
Set the mechanism in the playback mode with no
2.
cassette tape in place. Unplug the power cord.
Set the idler gear in the center (neutral).
3.
a
Removal (Supply reel disk)
Remove the tension band 0. (Take care not to
1.
deform it.)
Unscrew the screw @ and remove the supply reel
2.
retainer assembly
Release the supply reel disk catch @ and back
3.
tension lever
4.
Pull the supply reel disk upward.
Notes:
1.
Take care not to deform the tension band.
2.
Check and adjust the tension pole position. (See
page 30.)
3.
Be careful not to damage the gear and the idler
gear on the supply reel disk.
4.
Press the tension band in the direction of the
arrow for removal (See Figure
8.
0.
1-20(b)).
0
Removal (Take-up reel disk)
1.
Unscrew the screw
@
and remove the take-up
reel retainer.
2.
Release the take-up reel disk catch
3.
Pull the take-up reel disk @ upward.
Take-up
reel disk
Figure
l-21.
0.
e-up reel
retainer
Note:
When the tension band is pressed in the direction
of the arrow for removal, the catch is hard to be
deformed.
0
Reassembly (Supply reel disk)
1.
Clean the reel disk shaft 0 and apply oil to it.
2.
Release the supply reel disk catch Q and back
tension lever
3.
Install a new supply reel disk @ onto the shaft.
4.
Replace the tension band
0.
($9
around the supply
reel disk, and insert it to the hole of the tension
arm.
5.
Replace the supply reel retainer assembly @ in
place, and tighten up the screw
@.
Notes:
1.
Take enough care not to deform the tension
band during installation of the supply reel disk.
2.
Be careful not to damage the supply reel disk
gear, back tension lever, supply reel disk catch,
or the Ii ke with tools.
5 Tension band
Q
-.
(b)
Figure
l-20.
24
Figure
l-22.
Supply reel
disk catch
0
Reassembly (Take-up reel disk)
Clean the reel disk shaft 0 and apply oil to it.
1.
Release the take-up reel catch @ and video
2.
search brake lever
Install a new take-up reel disk @ onto the shaft.
3.
Replace the take-up reel retainer @ in position
4.
and tighten up the screw
0.
0.
Note:
Take care not to damage the video search brake
lever.
Take-up
reel disk
Apply a thin tip driver to the arrow position in
releasing for easier setting of the take-up reel disk.
Clean the reel disk shaft well,
and
aoolv
oil to it.
Set the master plane releasing
the reverse guide by a finger.
guide
Master
Figure
l-25.
1.
For height adjustment, press the reel disk with a
finger, and turn it right and left with a
screwdriver (see Figure
2.
Check that the reel disk is lower than part A but
1-26
(a)).
higher than part B. If the height is not correct,
adjust the height adjusting screw (see Figure
26 (W.
Note:
Whenever replacing the reel disk, perform the
height checking and adjustment.
l-
Figure
l-23.
* After reassembly, check the video search rewind
back tension (see page
torque (see page
l
Height checking and adjustment
30).
28),
and check the brake
Note:
Place the master plane onto the mechanism unit,
taking care not to hit the drum (see Figure
Setting
l-24).
Master plane
lOfO.Zmm
-
r -
1
Reel disk
I
9
(4
Slide it right and left,
and check contact with
”
I f
’ y, ‘,‘, ,
L
c-c=~Z “fc &I-
‘-
]
I
0
Reel disk height
adjusting jig
/Mechanism chassis
Figure
l-24.
25
(b)
Figure
l-26.
VT-341 8X
VT-5118X
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN FAST FORWARD MODE
l
Remove the cassette housing control assembly.
l
Setting
Torque gauge
Set the scale to
“0”
Setting
+
Figure
/
Take-up reel disk
l-27.
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN REWIND MODE
l
Remove the cassette housing control assembly.
l
Setting
Torque gauge
Set the scale to
“0”
Figure
l-29.
l
Checking
Turn the torque gauge slowly
(one rotation every 2 to 3
seconds) by hand in the
take-up direction
700gcm
The gauge is held at
Id
Figure
l Adjustment
1.
If the take-up torque is outside the range, clean
the capstan
D.D.
motor pulley, reel belt and reel
its maximum value.
(Red mark)
Take-up direction
l-28.
or more
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.
l
Checking
Turn the torque gauge slowly
(one rotation every 2 to 3
seconds) by hand in the
take-up direction
700gcm
The gauge is held at
its maximum value.
Figure
l-30.
l
Adjustment
1.
If the take-up torque is outside the range, clean
the capstan
D.D.
motor pulley, reel belt and reel
or more
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.
26
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN PLAYBACK MODE
1.
Remove the cassette housing control assembly.
2. Ooen
the lid of the cassette torque meter, and
hold it with two pieces of vinyl tapes.
Open here
Cassette torque meter
Load a cassette torque meter into the unit.
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN VIDEO SEARCH REWIND MODE
l
Remove the cassette housing control assembly.
a
Checking
\‘I//
VSR -
0
‘/ ,,:
/
1
/
?
Push the play button to place
the unit in the playback mode.
Push video search rewind
button to place the unit in the
video search rewind mode.
Set value
l
Checking
1.
Check that the torque is in the range of 95 2
SP95 + 30gcm
n
Figure
l-31.
g-cm.
2.
The torque fluctuates due to the rotational
deviation of the reel drive unit. Use the center of
the fluctuation as the value.
3.
Place the unit in the EP record mode, and check
that the take-up torque is within the range.
Torque gauge
Place the torque gauge on the supply 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
170 f: 40gcm.
Figure
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 rewind mode
is outside the range, replace the supply reel disk.
30
Note:
The torque fluctuates due to the rotational
deviation of the supply reel disk. Use the center of
the fluctuation at the value.
l-32.
v
.N
I7
Supply reel disk
l
Adjustment
If the take-up torque in the playback mode is
outside the range, replace the take-up reel disk.
Note:
Stabilize the cassette torque meter to prevent
floating.
27
CHECKING THE FAST FORWARD BACK
TENSION
l
Remove the cassette housing control assembly.
l
Checking
CHECKING THE VIDEO SEARCH REWIND
BACK TENSION
Remove the cassette
l
l
Checking
housing control assembly.
\‘I//
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 within
15 f 5gcm.
Figure
l-33.
Supply reel disk
Note :
Set the torque gauge securely on the supply reel
If the torque gauge is not securely set on the
disk.
reel disk, measurement will be incorrect.
CHECKING
l
Remo
THE
REWIND BACK TENSION
ve the cassette housing control assembly.
\‘I//
Push the play button to place
the unit in the playback mode. button to place the unit in the
Place the torque gauge on the take-up reel
disk, and turn it counterclockwise very
(one rotation every 2 to 3 seconds) and check
that the torque is within the set value
45
5 2Ogcm.
Push the video search rewind
videosearch rewind mode.
Torque gauge
s10wly
Figure
l-35.
\\I//
Note :
Set the torque gauge securely on the take-up reel
disk. If it is not secure, the measurement will be
incorrect.
Take-up
reel disk
Check
:ing
Place the unit in the
rewind mode.
Take-up reel disk
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 15 t
Figure
l-34.
5gcm.
l
Note:
Set the torque gauge securely on the take-up reel
disk. If it is not secure, the measurement will be
incorrect.
CHECKING THE PINCH ROLLER PRESSURE
Remove the cassette housing control assembly.
l
Capstan shaft
rusn the play button to place
unit in the playback mode.
ension gauge adaptor
the
28
Figure
l-36.
I.
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
1000
to
1200 g.
CHECKING AND ADJUSTMENT OF TENSION
POLE POSITION
l
Remove the cassette housing control assembly.
l
Setting
\‘I//
VT-341
8X
VT-5118X
2.
At the beginning of the tape
the tension pole’s left side is aligned with the
supply impedance roller’s center by sight.
3.
Check that the end of the tape is neither curled
against the flange of the supply impedance
roller nor over it.
4.
During the video search rewind mode with no
cassette tape in place, check that the supply reel
disk is free from the tension band.
l
Position adjustment (record mode)
When the tension pole is at the right of the supply
impedance roller’s center:
Untighten the tightening screw, and shift the
tension band adjustment bracket in the direction of
the arrow using a tension band and plate adjusting
Jig until it is in the set value range (center). Then
secure it with the tightening screw.
(Center
(E-180),
check that
Guide roller A
F. E.
head
SUPPlY
impedance.
roller
Check the left
side position
(by sight).
g-&n arm&YkPes
Place the unit in
the record mode.
roller B
.Guide
Center
I
/-SUPPlY
:
impedance
roller
Tension
pole
‘ension band adjustment bracket
T
l
Position adjustment (record mode)
I)
Tension band
and plate
adjusting jig
Figure
l-38.
When the tension pole is at the left of the supply
impedance roller’s center:
Untighten the tightening screw, and shift the
tension band adjustment bracket in the direction of
the arrow using a tension band and plate adjusting
Jig until it is in the set value range (center). Then
secure it with the tightening screw.
/enter
Tension
and plate
adjusting jig
setting hole
band’m
l
Checking
1
Video Cassette tape (E-l
b)
Figure
l-37.
I. The guide rollers (A, B) operate to bring the tape
outside the cassette tape and simultaneously the
tension pole moves to the left, loading the tape.
At that time (loading completed), check the
position of the tension pole.
80)
500
g
<Center
I
I
Supply impedance
roller
!
Tension
a
pole
lir
Tension band adjustment bracket
I)
Tension band
and plate
adjusting jig
Figure
l-39.
VT-341 8X
VT-5118X
CHECKING AND ADJUSTMENT OF
RECORD / PLAYBACK BACK TENSION
l
Remove the cassette housing control assembly.
l
Checking
Tension spring
cf*
\
Weight a
VI
\\‘I/
_‘
9
I.
Put a cassette torque meter into the unit.
2.
Push the record button to place the unit
record mode.
3.
Check that the back tension indicated by the
gauge is within the set range 31 to 36
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.
/
REC -
/
.
Cl
‘1
I\’
Push the record button
to place the unit
in the record mode.
Figure
l-40.
chassis
i-n
g-cm.
\
the
Tension spring hook plate
Figure
/Tension
Tension spring
hook plate
l-41.
spring
CHECKING THE BRAKE TORQUE
l
Checking the brake torque at the supply side
Torque gauge
‘,ysply
reel
l Adjustment
1.
If the reading of the cassette torque meter is less
than specified, move the tip of the tension spring
hook plate toward the hole A.
2.
If the reading of the cassette torque meter is
more than specified, move the tip of the tension
spring hook plate toward the hole
Note:
Put a thin screw driver
it toward you, and turn it for easier shift of the
tension spring hook plate in the direction of A or
B.
(-)
in the shaft hole, lean
B.
l-42.
130 g-cm,
CCW
direction.
idler gear
250
to
and that the
djust the
Mechanism chassis
1 I
Remove the cassette housing control assembly.
2.
Place the mechanism in the stop mode by
unplugging the power cord in the fast forward
or rewind mode.
3.
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 =
CCW
direction
brake torque in the CW direction is at least twice
as high as that in the
m
Figure
=90
to
30
(CCW)
750 gem,
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