Supertech TVR-004/B User manual

_Supeled
SOUND & VISION
SERVICE
IMIANUAL
MODEL
:
TVR-004/B

TV BLOCK DIAGRAM
TV/AV CONTROL
SF
DET IC
DIGITAL TUNING
AND BAND Sw
ICR4
MEMORY V.S.
A ae ae MICROCOMPUTER
RECEIVER VIDEG/VDR IN
s
(wc4053) be
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CONTROL

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i
|
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ALIGNMENT PROCEDURE
REGULATOR ADJUSTMENT
. CONNECT TV UNIT TO DC 12V~14V POWER SUPPLY & TEST PATTERN GENERATOR.
. CONNECT A DC DIGITAL VOLTMETER OR OTHER PRECISION ACCURACY VOLTMETER
TO THE COLLECTOR OF THE REQULATOR OUTPUT TRANSISTOR QPO1 (OR ANY 10.8
VOLT POINT OR TP1). :
3. ADJUST HORIZONTAL HOLD VRV1 UNTIL THE PICTURE HOLD IN SYNC.
. VERTICAL HIGHTNESS ALIGNMENT
ADJUST THE VERTICAL HIGHTNESS VRV2 ENABLE THE CIRCLE OF PICTURE APPROACH
TO CIRCLE.
HORIZONTAL POSITION ALIGNMENT
ADJUST HORIZONTAL POSITION VRY2, LET THE SQUARE SIGNAL IN THE CENTER OF
THE SCREEN.
RF AGC ALIGNMENT
ADJUST VIF MODULE AGC CONTROL VRI1 AT INPUT SIGNAL INTENSITY SOdB, THE
SCREEN COULD LOOKING CLEAR AND 80dB THE SCREEN DON’T INFLECT.
. WHITE BALANCE ALIGNMENT
ADJUST THE SVR602, SVR601, AT CENTER POSITION, ADJUST SCREEN VR, LET THE
SCREEN WILL BE LITTLE BRIGHTNESS. ADJUST SVR602 LET THE SCREEN TO BE
YELLOW, AND THEN ADJUST SVR601 LET THE SCREEN APPROACH TO WHITE.
. FOCUS ADJUSTMENT
ADJUST FOCUS VR, LET THE STRIP LINE ON THE SCREEN TO BE CLEAR.
ALIGNMENT PROCEDURE
GENERAL ALIGNMENT INSTRUCTIONS
. VIDEO IF ALIGNMENT
TEST EQUIPMENT CONNECTION (SEE FIGURE)
OSCILLOSCOPE: CONNECT TO (1) ICI1 PIN16
(2) 1Cl1 PIN11
SWEEP GENERATOR: CONNECT THROUGH A MATCHING PAO TO TEST POINT (TP2)
OF THE TUNER.
MARKER GENERATOR: COUPLE LOOSELY TO THE OUTPUT CABLE OF SWEEP GENERATOR.
DC SUPPLY: ADD DC +12V AT OC JACK
ADJUST SWEEP GENERATOR TO LOWEST SIGNAL LEVEL CONSISTENT WITH USABLE
STEP SWEEP FREQUENCY MARKER FREQUENCY REMARK
1) ADJUST VIF 30~50 MHz FOR | SYSTEM 8,G,H, 36.7MHz | PARENTHESIS
MOD. TI0O2 FOR| NTSC 65MHz FOR | SYSTEM | 37.3 MHz FOR EXCEPTION.
MARKER POINT | JAPAN). SYSTEM M,N 44MHz
MAXIMUM. 25645 MHz FOR | (S7MHz FOR JAPAN)
CCIR. (34.7 MHz FOR AUSTRARIA |
SYSTEM)
2) ADJUST VIF 30~50 MHz FOR | SYSTEM 8,G,H, 36.7MHz | IN THE
MOD. TI01 FOR | NTSC 65MHz FOR] SYSTEM | 37.3 MHz PARENTHESIS
MARKER POINT | JAPAN). SYSTEM M,N 44MHz FOR AFC
CENTER 25~45 MHz FOR | (S7MHz FOR JAPAN) CORRECTION
CCIR. (34.7 MHz FOR AUSTRARIA
SYSTEM)
OSCILLOSCOPE
SWEEP
GENERATOR
RF O/P H
MARKER
GENERATOR (1) VIF MOD. PINS
(2) VIF MOD. PING
O TP OF TUNER
VIDEO IF ALIGNMENT CONNECTING FIGURE

ALIGNMENT PROCEDURE
2. VERTICAL DEFLECTION ALIGNMENT
(1) TUNE THE RECEIVER IN A TEST PATTERN.
(2) ADJUST V~SIZE CONTROL VRV2 TO MAKE
THE INSIDE OF THE LARGEST CIRCLE OF TEST PATTERN REACHES NEAR ROUND
PATTERN. (SEE THE FIGURE)
PICTURE SCREEN
THE LARGEST PATTERN

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VDR POWER
MEASUREMENTS TO DETERMINE THAT EXPOSED PARTS ARE
PROPERLY INSULATED FROM THE SUPPLY CIRCUT.
CAUTION
;
THE
PARTS
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AN
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ARE
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SAFETY
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OR
SPECIFIED
WN
THE
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NOT
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THE
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SCHEMATIC DIAGRAM

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AUDIO
SCHEMATIC
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ELECTRICAL
ADJUSTMENT
1-1, ALIGNMENT AND ELECTRICAL ADJUSTMENT
The
suitable
wavefora
of
the
color-bar
signal
generator
is
show
below,
For these adjustment, use the equipment mentioned
below and proceed by using the alignment tape and
video signal,
Instrusent and Tools Required.
.
Color
TV
receiver,
’
OV
edi
ioacsee
ba)
ing
Ome
or
aster
beeen
Me)
.
Color-bar
generator,
0.3V
Frequency
counter.
VTVM
VOM
Audio osciliator,
0.V
aa Horizontal sync
Color ber signal waveform
erNanwawno
. Audio attenuator,
Signal Level and Input and Output
Tmapedance Requirement,
1. Video input: Negative sync., 1Vp-p standard composite
‘ video signal, 75Q.
2. Video output: Same as above.
3. Audio input: Line - 10dBs, 47KQ.
4. Audio output: -50dBs,10KQ or less.
Serva & Logic Alignment
Color Video Audio
Alignment Alignment Alignment
Adjustment Sequence
The VCR should be adjusted in the sequence shown below.
1-2, SERVO-LOGIC CIRCUIT ADJUSTMENT METHOD
1, VIDEO HEAD SWITCHING POSITION
Adj,
Location
Checking
Point
Measuring
Equipment
[amie
|
tent
Toe
|
PTOL 3PIN Oscilloscope Play
TPS4 |
1) Play back the test tape.
2) Set the oscilloscope in the CHOP mode connect the CH] to SW pulse PTOL 2 PIN the CH2 to TP54
(v, out) with CHI triggering.
3) Adjust RV11 for the positive trigger until 6.5H+0.5H cycles before the vertical SYNC pulse.
1-3. VIDEO CIRCUIT ADJUSTMENT METHOD
1. E E VIDEO LEVEL
Checking Point Measuring Equipment wots |
1) Feed the color bar signal to the line input terminal. And set for the stop (EE) mode.
2} Connect the. oscilloscope to TP55 and trigger the scope with a composite SYNC signal-at TPS3.
(COMP. SYNC, )
3) Adjust the oscilloscope so that it can display a waveform of approx, 2H.
4) Adjust RVS5 to obtain 0.52+0.02Vp-p between SYNC TIP and 100% white level.
Test Tape
0.5£0.02Vp—p

2. PLAYBACK Y-SINGAL OUTPUT LEVEL
as
secs
=
re
peers
|
ve
|
1) Playback the test tape (Color Bar aS
2)
Connect
the
oscilloscope
to
TP54
and
trigger
the
scope
will
a
composite
SYNC
signal
at
TPS53.
Adjust
the
scope
so
that
it
can
display
a
wavefora
of
approx.
2H.
3)
Adjust
RV56
to
optain
2.0+0.2
Vp-p
between
the
SYNC
TIP
and
100%
white
level,
PT tt et | tl
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Ai Pi...
amo el HIVES Lummis ‘
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Pie ee er ee
3. SYNC TIP FREQUENCY
ae ae oe cc ouaal
1)
Set
the
unit
to
NTSC mode
without
video
signal.
(Jack
of
video
line
input
is
shorted
with
gro-
und),
2) Connect the frequency counter to TPS2.
3)
Adjust
RV54
until
the
SYNC
TIP
frequency
becomes
3.
4MHz
+0.
LMHz,
4) Set the unit to N-PAL mode.
5)
Adjust
RV53
until
the
SYNC
TIP
frequency
becomes
3.
8MH+
20,
LMHZ.
4, LUMINANCE AND COLOR RECORD CURRENT
Atel pag
1) Input Color bar signal in video Line in.
2) Make every adjustment in REC mode. :
3) Connect CH.1 of oscilloscope to TP51 and TP GND and CH.2 TPS3 (C.SYNC), and then trigger the
scope with an externa! signal.
4) Adjust RVS2 Until the color record current level (RED REFERENCE) becomes 70+:5mVp-p.
5) Connect CH.1 of oscilloscope to TP5! and TP GND and CH.2 TP53 (C,SYNC), and then trigger the
scope with an external signal.
6) Adjust RV51 Until the Sync. Luminance level becomes 300+10mVp-p.
ie
a: 7OmzSmp—p
ee:

5. FM DEVIATION
RVS7
TPS4
Oscilloscope
PB
&
REC
Blank
Tape
1) Confirm that the adjustment for the playback Y-Singal output level fas been made corretly.
2) Feed the color bar signal to the line terminal, and set the VCR to the record sode.
3) Connect the oscilloscope to TPS4 and trigger the scope with a composite syne signal (TPS1).
4)
Record
the
color
bar
signal
for
a
few
minute
and
playback
it.
Then
confirm
that
the
playback
Y-signal output level is 2.040. 2Vp-p.
5) If the playback Y signal output Jevel is not 2.00.2 Vp-p, the adjust as follows.
5-1) Set the VCR in the record mode.
5-2) Turn the variable RV57 a little.
5-3) Record the color bar signal for a few minute and playback it.
5-4) Confirm the playback Y signal output is 2,020.2 Vp-p.
5-5) Repeat from step 5-1) until the playback Y-signal oytput level become 2.0+0.2 Vp-p-between
the Sync. TIP and 100% while level.
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eee
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0.5V/div
5. RECORD-PLAYBACK OUTPUT LEVEL
ied asc
Checking Audio Line Out -
sours es
REC. Play Blank Tape
1) Connect the audio signal generator to the audio line input jack,
2) Record and playback the input of the audio reference signal 1KHz, -10dBa.
3) Connect that play output level is -5+3dBm as referenced to the playback output level.
Audio Level Meter
Audio Signal Generator

1-4, AUDIO CIRCUIT ADJUSTMENT METHOD
1. PLAYBACK OUTPUT LEVEL
RV61 Audio Line Out Audio Level Meter oe Mode
1) Connect the audio level meter to the audio line output jack.
2) Play back the test tape.
3) Adjust RV61 until the audio level meter reads -6,0-+1.5dBm play back output.
2. PLAYBACK OUTPUT FREQUENCY CHARACTERISTIC
pone pears peviidass . ae
Audio Level Meter PLAY Mode 1KHz, OdBa
6KHz, OdBa
1) Playback the Test tape, and confirm that the playback output “Level at 6KHz is within 0+3dB
as referenced to the 1KHz Playback output level. .
Audio Line Out
3. BIAS CURRENT ADJUSTMENT AND OSCILLATION FREQUENCY CHECKING
sss eee Basen pre
*%
1) Supply the signal in the OPEN mode.
2) connect the positive lead of the VIVM to TP6l Lpin and negative lead to TP61 2pin.
3) Set the VCR in recording mode.
4) Confirm the frequency counter display is 70KHz+10% and adjust RV62 until VIVM reads 2,3 aVras.
4, RECORD-PLAYBACK FREQUENCY RESPONSE
pieces . sie
REC, Play Blank Tape
1) Connect the audio- signal generator to the audio line input jack, and the audio level meter to
the audio line output jack,
2) Record reference audio signal to the 400Hz and 8KHz (SP) ‘audio signal at-20 dBs.
3) Check to insure that 8KHz and playback output level! is within -1+3 dB as referenced to the
400 Hz playback output level. (SP) ,
4) If the difference between 8KHz and 400Hz playback output level is more than +1 dB, increase the
bias current more than 2.3mVms, and if the difference is less than -3dB, reduce the bias current
less than 2, 3mVas.
Audio Level Meter
Audio Signal Generator
Audio Line Out
1. MECHANICAL ADJUSTMENT
1-1.
CHECK
FOR
THE
MECHANICAL
POSITION
Check
for
the
following
matters
before
disassembly,
replacement
and
reassembly.
1)
Make
sure
of
the
assembly
base
of
the
Deck
Mechanism
in
the
EJECT
MODE.
2)
Make
sure
of
the
assembly
position
among
the
Cam
Gear
and
several
parts
Defore
assembling
the
L/C
Bracket
Total
Ass'y
(refer
to
Fig.
1-1,2,3,4).
3)
Make
sure
of
the
assembly
position
between
the
Loading
Rack
and
the
R
&
LLoading
Ass'y
(refer
to
Fig.
1-5).
4)
Make
sure
of
the
position
of
the
Cam
Switch
when
assembling
the
LC
BRKT
Total
Ass'y
(refer
to
Fig.
1-4).
5)
Make
sure
of
the
assembly
state
of
the
Front
Loading
Ass'y
(refer
to
Fig.
1-7).
6)
Make
sure
of
the
other's
assembly
state
(refer
to Fi
ig.
1-8):
OATUM HOLE SS
OF ASSEMBLY 5°
CAM FIL SUB Uk
GEAR RACK
“Note:
oe
of
assembly
should
be
located
in
=0~5°
Fig. 1-2 Reference of assembly for the Fil Sub
Rack and Cam Gear
5
Fig.
1-1
Reference
of
assembly
for
the
Cam
Gear

DATUM HOLE OF RELAY LEVER
DATUM HOLE OF MAIN BASE
CONFIRM POLY WASHER-FIT _
CONFIRM POLY
WASHER-FIT (T=0.5)
PINCH LEVER
TOTAL AS
Fig. 1-4 Reference of assembly for the Cam Gear and Pinch Lever
CONFIRM ASSEMBLY POSITION
CONFIRM POLY WASHER-FIT (t=0.5)
CONFIRM
CONFIRM
ASSEMBLY
MARK
SNAP-FIT
R LOADING AS L LOADING AS
BELOW 7mm
CONFIRM ASSEMBLY POSITION a
Fig. 1-5 Reference of assembly for the Loading Rack and A/L Loading AS
SCREW (TT3 AND 3x6)
Fig. 1-6 Reference of assembly for the Cam Switch Fig. 1-7 Reterence of assembly for the Front Loading As
*Note: 1. The 4 Shape of Rotor should be located in *Note: 1. It should be returned to its original state when
6=0~5°. the safety lever was pushed by hand.
2. The above figure is a reference bottom view for 2. On fastening screw, that above 6mm shouid not
the UC bracket Total AS. be used (In the case of using non-specification
screw, the Capstan PCB is deformed.)

Confirm Connector AS
it should be contacted
with the FRee! Table
| /in Contirm the assembly
state of spring
é
Confirm
1.5~3.0mm
of
clearance
between
Idler
Bracket
and
both
Main
Brake
Fig.
1-8
Reference
of
assembly
for
the
other
parts
1-2.
HOW
TO
SET
MECHANICAL
MODE
F
h
{TIAL
MOOE
and
then
power
off.
1)
On
removing
the
Front
Loading
Ass’y,
Syscon
executes
the
IN
H
If
the
pone
is
on
in
the
INITIAL
MODE,
it
executes
the
STOP
MODE.
Pr
button
you
want.
;
2)
ON
waar
the
toque
mode,
pull
out
the
power
plug
if
necessary.
5)
If
the
STOP/EJECT
button
is
pushed
in
the
STOP
MODE
or
EJECT
MODE,
mode and then power off. we
6)
Reassemble
the
Front
Loading
Ass'y
in
the
only
EJECT
MODE.
it returns to the INITIAL MODE via the EJECT
1-3. Measurement of Pressing Force for Pinch Roller
1) In @ state of removing th Front Loading Ass‘, pull out
the
power
plug
after
playing
back
without
cassette,
2) Remove the LIC Bracket Tota! Ass'y and the Worm Wheel.
3)
Pull
the
push-pull
gauge
to
the
direction
‘A’
indicated
by
the
arrow
as
shown
in
Fig.
1-9.
7
4) Confirm that the scale of push-pull gauge is 1.2+0.2 Kg
at the mcemnt of the Pinch Roller separating from the
Capstan Shaft.
§) If it is out of specification, repiace the Pinch Roller Spring
or the Pinch Lever Tota! Ass’y.
1-4,
The
Measurement
and
Adjustment
of
Back
Tension
1)
Play
back
7-120
tape
at
its
center
position
without
Fil.
\
Ass'y,
wait
until
the
driving
of
tape
is
stabilized
(about
10
~20
seconds).
2)
Set
the
Tentelometer
as
shown
in
Fig.
1-10
and
confirm
the
scale
(SPEC:
22
~30g).
3)
If
it
is
out
of
specification,
change
the
position
of
Ten-
sion
Spring
in
order
to
adjust
the
tension
value.
NOTE:
1. Make sure that the three probes of the Tentelometer
are ail in good contact with tape.
2.
It
is
recommended
to
te
measured
three
times
as
Tentelometer
is
very
sensitive.
TENTELOMETER
PROBE
Fig. 1-10
1-§. The Height Adjustment of Reeil-Table
1) Put the master into the Hole S and the Hole T in the Jig
(TSH-V4) and set the Dial Gauge to zero. ;
2) Set the Jig (TSH-V4) on the Deck Ass’y as shown in Fig.
4-11 and check the height of Reel Table
(S: 040.1 T O28
3) If it is out of range, it is necessary to adjust the height
of Reet Table by adding or subtracting the Poly Slider as
shown in Table 1-1.
[aiamm | —ssrseeoa76o
[o2smm | ___a7saeoaa00 «st
[905mm 9783903600 -
Table 1-1 Poly Slider for Adjustment

Dial Gauge
——
Hole S Hole T
anece
1-6. The Measurement of Ree! Torque
1) Play back the Cassette Type Torque Meter.
2) Measure the Take-up Reel Torque after the tape running
is stabilized (SPEC: 90~170 em).
3) If it is out of range, replace the Reel Gear Total Ass'y.
2.
THE
ADJUSTMENT
OF
TAPE
TRANSPORTING
SYSTEM
The
tape
transporting
system
has
been
precisely
adjusted
at
the
factory
and
does
not
ordinary
require
readjustment.
But
when
the
noise
and
tape
damage
takes
place
and
parts
that
compose
the
tape
transporting
system
are
replaced
due
to
troubles
by
long
usage
or
unexpected
accidents,
check
and
readjust
the
tape
transpoting
system.
21. THE SCHEMATIC DIAGRAM OF TAPE TANSPORTING SYSTEM
ADJUST CAP
AZIMUTH ADJ. SCREW
@ VERTICAL POST @ FSLANT POLE
@® TENSION POLE @ FGUIDE ROLLER
@ S-GUIDE POST @ AC HEAD
@ FE HEAD @ TFGUIDE PosT
® SGUIDE ROLLER @ CAPSTAN SHAFT
@® S-SLANT POLE @ PINCH ROLLER
@ CYLINDER

2-2.
ADJUSTMENT
FLOW
FOR
THE
TAPE
TRANSPORTING
SYSTEM
—
*ORUM TOTAL ASS'Y
“DRUM MOTOR ASS'Y
eAC HEAD ASS'Y
“PINCH LEVER
“TOTAL ASS'Y
7KHz(NTSC)
8KHz(PAL)
STAIRSTEP or
MONOSCOPE
Adjust time interval of 6.5 H
between switching pulse and
V sync signal
Replacement
*S-POLE BASE ASS'Y
*T-POLE BASE ASS'Y
“TENSION LEVER ASS'Y
SP. EP(LP)
CHECK TRANSITIONAL
6 | OPERATION FROM
REVIEW TO PLAY
Record signals on T-120 TAPE in EP and
ENVELOPE CHECK
SP mode and play back the signals
8
FINE
CHECK
—
Make
sure
no
tape
wrinkle
is
caused
at
each guide
Make sure that entrance envelope nses
. within 3 seconds in the standard Play mode
after servo locking
2-3. ADJUSTMENT PROCEDURES -
1) Preadjustment
When the parts as shown in Fig. 2-1 is replaced, the Tape
Path may be changed and alignment tape may be darnag-
ed. To prevent this, first, playoack a 7120 Tape and make
sure excessive tape wrinkle does not occur at each tape -
guide.
if tape wrinkle is observed at the S & Guide Roilers (@,
@) in Fig. 5-1, turn the S & TGuide Rollers for no wrinkle.
2) The Pre-adjustment of AC Head Ass’y
A. Tilt Adjustment
a. Play back a 7120 Tape and observe running condition
of the Tape at the upper and lower Flanges of the r-
Guide Post Ass'y @ in Fig. 2-1.
b. Adjust the Tilt Adjusting Screw until tape runs stabie
as shown in Fig. 5-2.
> Turn the tit adj screw cow
TAPE -——=
aN
a
; Turn the tlit adj screw cw
Fig. 2-2 FGulde Post
8. Audio Azimuth Adjustment
a. Play back the Alignment Tape (SP mode) with audio
singal.
¢ NTSC: 7 KHz
b. Observe audio signals on an oscilloscope.
c. Turn the Azimuth Adjusting Screw to obtain maximum
audio output.
© PAL: 6 KHz
ADJUST CAP
AZIMUTH ADJ SCREW
TILT ADJUST SCREW
Fig. 2-3
C. The height Adjustment of AC Head
a. Play back the Alignment Tape (SP mode) with 1 KHz
audio singal.
b.
Tur
the
Ac
Head
Nut
to
obtain
maximum
audio
output.
©
0.1=0.05 mm
Fig. 2-4 The Height Adjustment of AC Head
D. The X-position Pre-adjustment of AC Head
a. Play back the Alignment Tape with SP stairstep (or
monoscope) singal.
b. Adjust the Adjust Cap for maximum envelope output,
after Tracking Volume is set at its center click position.
NOTE:
Before proceeding with this adjustment, remove fock-
ing paint applied on the Adjust Cap.
3) Playback Phase Adjustment (PG Adjustment)
A. Play back the Alignment Tape (SP mode).
B. Observe a video signal on an oscilloscope display trig-
gered with the switching pulse.
C. Adjust the PG volume for time interval of 6.5 H+0.5 H
between switching pulse and V sync signal.
NOTE:
In this adjustment, adjust the Tracking Volume the
best video signal.
Switching puise
Sa
i)
SEE a
' ; '
Video Signal Piles edge af V sync.
1
'
H
!
| g.520.5H
Fig. 2-5 Playback Phase Adjustment

CONNECTION
a a
JIG PCB
2
a
a
ae
ON/OFF 5V 6 | 6 |
TP3
OSCILLOSCOPE
[enve | ~tneany Adjustment
X-Position Adjustment
Envelope Check
| vioeoour | OuT Play back Phase Adjustment
[ svooour_ | OUT Audio Head Adjustment
(Height, Azimuth)
| wo |——[_ ao]
MAIN PCB
ADJUSTMENT VR
R591
MAIN TRACKING VR VRi (JIG PCB)
PG VR R591 (MAIN PCB)
O wa:
0
4) Linearity Adjustment
A. Play back the Alignment Tape ain SP stairstep {or
monoscope) signal.
8. Observe the singal envelope on an wacnsacose display
triggered by the switching pulse.
C. Make sure the envelope waveform (in its maximum) out-
put meets the specifications shown in Fig. 2-6.
a. Maximum output of envelope.
b. Minimum output of envelope at the Drum entrance
¢ Minimum output of envelope at the Drum center.
d. Maximum output of envelope at the Drum exit in
Fig. 5-6.
Fig. 2-6 Envelope Wareform Specification
D. If the section A in Fig. 5-7 does not meet the specifica-
tion, adjust the S-Guide Roller up or down.
E. If the section B in Fig. 2-7 does not meet the specifica-
tion, adjust the T-Guide Roller up or down.
Fig. 2-7 Adjustment Point
F. After completing adjustment, turn the tracking Volume
and.make sure the envelope varies almost flat.
G. If the envelope varies as shown in Fig. 2-8, adjustment
of the S-Guide Roller and the -Guide Roller may be upset
and then perform the adjustment again.
a
en tena:
Fig. 2-8 Abnormal Waveform Variation
Orum entrance
Fig. 2-9 Waveform Adjustment at the Drum Entrance
TT
Drum exit
Fig 2-10 Waveform Adjustment at the Drum Exit |
Li
—
to
7
on
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Fig. 2-11 Normal Waveform Variation

5) The fine adjustment of AC head
A, Tilt Adjustment (refer to Fig. 2-2)
Tape iva check at the lower Flange of T-Guide Post Ass'y
in Fig. 2-1.
a. If tape wrinkle is observed at the lower Flange of @
adjust the Tilt Adjust Screw CCW until the wrinkle
disappears.
bo. If a gap observed between the lower Fiange of @ and
the lower edge of tape, adjust the Tilt Adjusting Screw
CW until the tape travels along the lower Flange.
8 Azimuth Adjustment (refer to section 2-3-2)
C. The X Pesition Adjustment for interchangeability
a. Play back the Alignment Tape (SP mode) with stairstep
(or monoscope) signal.
b. Place the Tracking Volume at its center click.
c. Trigger an oscilloscope with switching pulse and
observe the envelope waveform of CH-2.
d. Tur the Adjust Cap CCW or CW within taper section
and fix the Adjust Cap at the position where the
envelope reaches a peak level.
@ Play back the Alignment Tape (EP or LP mode) with
stairstep (or monescope) signal.
f. Make sure the envelope is maximum at the center
click position of Tracking Volume if maximum
envelope is not cbserved, perform the envelope ad-
justment to obtain maximum envelope output again.
g. Play back the Alignment Tape with stairstep (or
mMonoscope) signal and make sure audio output is
maximum.
e NTSC: 7 KHz = ® PAL: 6 Khz
AC head plate |
| Taper section
6) Check tor transitional operation from Review to
Playback
A. Playback the Alignment Tape (SP mode) in the REVIEW
mode and observe the envelope with an oscillescope.
8 Switch the REVIEW mode to the PLAY mode. Make sure
state within 3 seconds as shown in Fig. 2-13. If it does
not rise within 3 seconds after servo locking adjust as
follows.
a. Play back the Alignment Tape which has the stairstep
(or monoscope) signal, looking Envelope Waveform,
make sure that S & FGuide Roller's height is adjusted
correctly.
b, Change operation mode from Review mode to Play
mode again and then make sure that the entrance
envelope rises within 3 seconds after servo locking.
c If not, perform the adjustment according to the sec-
tion 2-3-4.
envance ENVELOPE exit ENVELOPE
7) Envelope Check ‘
A. Record video signals (color bar or monoscope on T-120
Tape) and make sure the playback envelope output
meets the specification as shown in Fig. 2-13.
8. in playing the same Video Deck used for the recording
using the 7-120, the envelope should meet the specifica-
tion as shown in Fig. 2-14.
C. If the performance does not meet both specification,
replace the Drum Total Ass’y.
Fig. 2-14 Envelope output and output level difference
8) Final Check
Make sure no Tape wrinkle is caused at each guide.

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