Akai VS-2EGN User manual

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AKAT Servite manu
VIDEO CASSETTE RECORDER
move. V §=2EGN (5 system)

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VIDEO
CASSETTE
RECORDER
mopeLVS-2EGN(5
System)
SECTION
1
SERVICEMANUAL
.........---.+--++-
1
SECTION
2.
PARTSLIST
........--.
20522202
eeeeee
141
SECTION
3.
SCHEMATIC
DIAGRAM
............+++-
160

SAFETY INSTRUCTIONS
SAFETY CHECK AFTER SERVICING
Confirm the specified insulation resistance between power cord plug prongs and externally exposed parts of the set is
greater than 10 Mohms, but for equipment with external antenna terminals (tuner, receiver, etc.) and is intended for
[C] or
» Specified insulation resistance should be more than 2.2 Mohms (ground terminals, microphone jacks,
headphone jacks. line-in-out jacks etc.)
PRECAUTIONS DURING SERVICING
2.
ower D
Parts identified by the A\ symbol parts are critical for safety.
Replace only with parts number specified.
In addition to safety, other parts and assemblies are specified for conformance with such regulations as those
applying to spurious radiation. These must also be replaced only with specified replacements.
Examples: RF converters, tuner units, antenna selector switches, RF cables, noise blocking capacitors, noise
blocking filters, etc.
Use specified internal wiring. Note especially:
1) Wires covered with PVC tubing
2) Double insulated wires
3) High voltage leads
Use specified insulating materials for hazardous live parts. Note especially:
1) Insulation Tape
2) PVC tubing
3) Spacers (Insulating Barriers)
4) Insulation sheets for transistors
5) Plastic screws for fixing microswitch (especially in turntable)
When replacing AC primary side components (transformers, power cords, noise blocking capacitors, etc.), wrap
ends of wires securely about the terminals before soldering.
> o>
Observe that wires do not contact heat producing parts (heatsinks, oxide metal film resistors, fusible resistors, etc.).
Check that replaced wires do not contact sharp edged or pointed parts.
Also check areas surrounding repaired locations.
Use care that foreign objects (screws, solder droplets, etc.) do not remain inside the set.

SECTION 1
SERVICE MANUAL
TABLE OF CONTENTS
I. SPECIFICATIONS
Ul. OPERATING PROCEDURE
1, RECORDING
9° PLAVYBAGR asic ees ah aici
Ill. DISMANTLING OF UNIT .......
IV. CONTROLS ............-.5-
V. PRINCIPAL PARTS LOCATION
VI. VOLTAGE CONVERSION ...........
VII, CIRCUIT DESCRIPTION
1, GENERAL
2, VS-2EGN VIDEO CIRCUIT OPERATION
3, SERVO CIRCUIT OPERATION
4, MECHANISM DRIVE OPERATION
5, OPERATION CIRCUIT
6.
7
8
9
. THE POWER/SYSCON CIRCUIT
. AUDIO/VIDEO PRE-AMP CIRCUIT
. BOOSTER CIRCUIT
. RF CONVERTER FUNCTIONS AND CIRCUITS
10. TV TUNER (FRONT END) FUNCTIONS AND CIRCUITS . .
11, DEMODULATOR FUNCTIONS AND CIRCUITS
VIII. MECHANICAL ADJUSTMENTS ...........-..--
1. TENSION LEVER POSITION ADJUSTME
2. BACK TENSION ADJUSTMENT ... Lara pant
3. CHECK THE VARIOUS TORQUES ............-
IX. REPLACEMENT OF VIDEO HEAD ASSEMBLY
X. TAPE TRANSPORT ADJUSTMENT
1. TAPE GUIDE HEIGHT ADJUSTMENT
2. GUIDE ROLLER HEIGHT ADJUSTMENT
3. AUDIO/CONTROL HEAD HEIGHT, TILT AND AZIMUTH ADJUSTMENT .........-...-- 103
4, CONTROL HEAD POSITION ADJUSTMENT . .. 2... 6-6 eee ee eee
5, ADJUSTMENT OF QUICK FINDER (REVIEW) RUN ...
XI. ELECTRICAL ADJUSTMENT
1, SERVO P.C BOARD ADJUSTMENT
2. VIDEO (EGN) P.C BOARD ADJUSTMENT
3. EGN P.C BOARD ADJUSTMENT
4, AUDIO/PRE P.C BOARD ADJUSTMENT
5. DEMODULATOR P.C BOARD ADJUSTMENT
XII. VARIOUS WAVEFORMS AT EACH TEST POINT ..
1. SERVO P.C BOARD . .
2. VIDEO P.C BOARD
3. EGNP.C BOARD ....
XII. P.C BOARD TITLES AND IDENTIFICATION NUMBERS
XIV. COMPOSITION.OF VARIOUS P.C BOARDS
For
basic
adjustments,
measuring
methods,
and
operating
principles,
refer
to
GENERAL
TECHNICAL
MANUAL.
Service Manual VS-2EGN

|. SPECIFICATIONS
FORMAT VHS Standard
VIDEO
RECORDING
SYSTEM
Rotary,
slant
azimuth
two-head
helical
scan
system
RF INPUT System B, G (PAL, SECAM)
VHF Ch 2 to 12
UHF Ch 21 to 69
RF OUTPUT System G type modulation
UHF Ch 30 to 39 adjustable (preset to Ch 36)
RECORDING (LINE INPUT) PAL, System B, G,I
SECAM, System B, G
NTSC, 4.43 MHz
NTSC, 3.58 MHz
PLAYBACK (LINE OUTPUT) PAL, System B,G,1
SECAM, System B, G
SECAM, System L
NTSC, 4.43 MHz
NTSC, 3.58 MHz
VIDEO
LINE INPUT LEVEL 0.5 to 2.0 Vp-p/75 ohms unbalanced
LINE OUTPUT LEVEL 1.0 Vp-p/75 ohms unbalanced
S/N More than 43 dB
HORIZONTAL RESOLUTION More than 250 lines (PAL)
More than 220 lines (SECAM)
More than 220 lines (NTSC)
AUDIO
LINE INPUT LEVEL —20 dBs/50 kohms unbalanced
LINE OUTPUT LEVEL —6 dBs/1 kohm unbalanced
S/N More than 40 dB
FREQUENCY RESPONSE 70 Hz to 8 kHz
RECORDING OR PLAYBACK TIME 240 min. with E-240 cassette (PAL, SECAM)
168 min. with E-240 cassette (NTSC)
160 min. with T-160 cassette (NTSC)
TAPE SPEED 23.39 mm/sec. (PAL, SECAM)
33.35 mm/sec. (NTSC, “standard play” mode only)
QUICK FINDER
PAL/SECAM Approx. 7 times the normal speed (noise bars fixed)
NTSC Approx. 5 times the normal speed (noise bars fixed)
FF., RWD TIME 4 min. with E-240 cassette
TIMER
PROGRAMS Nine 4-week-one time memory programs and one shut-off pro-
gram
CLOCK REFERENCE Locked to power line frequency (50/60 Hz)
DISPLAY TV screen (Tape counter, Timer, Clock and Calendar)
POWER REQUIREMENTS 110 (100—120)/220 (200—240)V, 50/60 Hz
POWER CONSUMPTION 45 watts
OPERATING TEMPERATURE 5°C to 40°C
DIMENSIONS 440(W) x 133(H) x 360(D) mm
WEIGHT 10.5 kg
* For improvement purposes, design and specifications are subject to change without notice.
Service Manual VS-2EGN

it. OPERATING PROCEDURE
1, RECORDING
1) From built-in Tuner (To record TV programs)
SIGNAL FOR
RECORDED. TAPE
PAL B/G | ve_
position | VS~2EGN
RECORDING
NOTE I
SECAM
B/G
SECAM
B/G
)
(Mice
East
SECAM
(aiaate East
SECAM
7
.
%
NOTE
1;
The
PAL
I
color
system
which
is
used
in
U.K
and
Hong
Kong
cannot
be
recorded
through
the
built-in
tuner.
2) From source connected to VIDEO IN jack
SIGNAL FOR
RECORDING
RECORDED
TAPE
PAL PAL B/G
B/G/H/1 POSITION
SECAM B/G
(iicale aie
SECAM
SECAM B/G
(Migate East)
SECAM
SECAM L
( Frenchy
SECAM
POSITION
NTSC NTSC 3.58
3.58MHz POSITION
Service Manual VS-2EGN ——————————— esse
3

2. PLAYBACK
1) On TV connected to RF OUT jack
RECORDED TAPE
PAL B/G
POSITION
TV
SECAM B/G
(iiadle East
SECAM
SECAM
B/G
POSITION
NTSC
4.43
POSITION
SECAM L
POSITION
NOTE 2
SECAM
POSITION
NTSC
4.43
POSITION
SECAM
POSITION
%
NOTE
2:
Use
a
TV
which
can
receive
the
PAL
B/G
color
system.
If
a
TV
which
can
receive
the
PAL
|
color
system
in used
no
sound
will
be
heard.
2) On TV connected to VIDEO OUT jack
RECORDED TAPE
SECAM B/G
(Missle East
SECAM
SECAM L
(Eeeneh.
SECAM
NTSC |
> B/G
POSITION
PAL B/G
POSITION
SECAM
U4
SECAM L
POSITION
NTSC
3.58
POSITION
4.43
POSITION
Service Manual VS-2EGN
PAL
POSITION
SECAM
B/G
POSITION
SECAM L
POSITION
NTSC
3,58 5-WAY
POSITION
NTSC S
4.43 SeWay.
POSITION

I.
DISMANTLING
OF
UNIT
Ss
In
case
of
trouble,
etc.
necessitating
dismantling,
please
dismantle
in
the
order
shown
in
the
photographs.
Reassemble
in reverse order,
FRONT PANEL —:
‘SCREWS
1 4
CASSETTE LID
SCREW
2 5
UPPER
CASE
‘SCREWS
SCREWS
3 6
-_oo
Service
Manual
VS-2EGN
5

Iv. CONTROLS
ONOINBHARONS|
10.
11.
Fig. 4-1 Controls (Front View)
» FUNCTION “OFF/TIMER” BUTTON
FUNCTION “ON” BUTTON
. PRESET (PS) STATION DISPLAY
}. CASSETTE HOLDER
. PRESET SELECT (A) BUTTON
DISPLAY ON/OFF (B) BUTTON
TIMER/SLEEP PROGRAM NO. BUTTON
} CLOCK BUTTON
|. PRESET BUTTON
EJECT BUTTON
TAPE TRANSPORTING BUTTON
REWIND (44 REW), STOP (ml STOP),
FAST FORWARD (F.F PP),
QUICKFINDER REVERSE (@) QUICK FINDER),
PLAY ( ® PLAY),
QUICKFINDER FORWARD (QUICK FINDER(@®D)),
RECORDING ( @ REC),
COUNTER “0” STOP, PAUSE ( Il PAUSE)
Service Manual VS-2EGN
Fig. 4-2 Controls (Rear View)
. TRACKING CONTROL
- COMPARTMENT FOR THE OPTIONAL REMOTE
CONTROL UNIT RC-V202
. COLOR SYSTEM SELECTOR
. FINE TUNING (D) BUTTON
. COUNTER RESET (C) BUTTON
» AC INPUT SELECTOR
. POWER ON/OFF SWITCH
. RF CONVERTER CHANNEL (CH.) ADJUSTMENT
(ADJ.) HOLE
ANTENNA (ANT.) IN JACK
. RF OUT JACK
. AUDIO JACK
. VIDEO IN JACK
. VIDEO OUT JACK
. REMOTE PAUSE JACK
j. AC INLET
|. TV/VIDEO BUTTON (EA MODEL ONLY)

V. PRINCIPAL PARTS LOCATION
1.
8
3.
4.
5.
6.
hh
8.
a.
10.
TAs
12.
13.
14,
15,
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
25 @4
OPERATION P.C BOARD V1009A5170
FUNCTION ON SWITCH
FUNCTION OFF/TIMER SWITCH
DIGITAL DISPLAY
PRESET SELECTOR (A) SWITCH
DISPLAY ON/OFF (B) SWITCH
TIMER/SLEEP/PROGRAM NO. SWITCH
CLOCK SWITCH
PRESET SWITCH
EJECT SWITCH
QUICK FINDER REVERSE SWITCH
REWIND SWITCH
PLAY SWITCH
STOP SWITCH
QUICK FINDER FORWARD SWITCH
FAST FORWARD SWITCH
PAUSE SWITCH
TRACKING VOLUME
COUNTER AUTO “0” STOP SWITCH
REC SWITCH
LED P.C BOARD V1009D5320
SYSTEM SWITCH
FINE TUNING (D) SWITCH
COUNTER RESET (C) SWITCH
BACK UP BATTERY
(6)
O®2®O® OOMQO®Q YO OOGL |©
2 Bea) BIg
Fig. 5-1 Parts Location (Front View)
Service Manual VS-2EGN

YV@2OSO®H © ODMOQD WO W &
1, S, IMPEDANCE ROLLER
2. AUDIO/PRE P.C BOARD V1009A5180
3. DRUM HEAD BLOCK
4, DEMODULATOR P.C BOARD
5. TV TUNER UNIT
6. CAPSTAN MOTOR
7. ANTENNA BOOSTER
8, MECH DRIVE P.C BOARD V1009A519B
9, RF CONVERTER
10. POWER FILTER P.C BOARD V1009D5210
11, POWER TRANSFORMER
12. POWER & SYSCON P.C BOARD V1009A519A
13. SOCKET FOR THE OPTIONAL REMOTE CONTROL
UNIT RC-V202
14. TAKE UP REEL
15. SUPPLY REEL
16. PINCHROLLER
17. FULL ERASE HEAD
18. AUDIO/CONTROL HEAD
Service Manual VS-2EGN

. DRUM MOTOR
, LOADING SWITCH A
EJECT SWITCH
LOADING MOTOR
REC. SAFETY SWITCH
LOADING SWITCH B
REEL MOTOR
. INTERMEDIATE P.C BOARD V1009A519C
. PLUNGER
. CAPSTAN FLYWHEEL
. CAPSTAN MOTOR
. TRACKING VOLUME
. EGN P.C BOARD
. SERVO (EGN) P.C BOARD
. VIDEO (EGN) P.C BOARD
Fig. 5-3 Parts Location
Service
Manual
VS-2EGN
9

Vi. VOLTAGE CONVERSION
POWER
:
ON OFF
AC INPUT —
[asm nov |
(ee g
110/220
50Hz~
pana
2)
~“@})
CONVERTER
ay
|
RF
ICH. ADJ. HOLE
Fig. 6-1 Voltage Conversion
Power requirements for electrical equipment differ from
area to area. The operating voltage of VS-2EGN is pre-
set to 220V. Before connecting, check that the AC IN-
PUT selector on the rear panel is set to the voltage for
your area:
110V, 50 Hz for other countries. If the AC INPUT is
not set for your area:
1. Confirm that the POWER Switch on the rear panel
is set to OFF.
2. Confirm that the POWER Cord is disconnected.
3. Move the AC INPUT selector with a screwdriver so
that the marker is above the voltage for your area.
Service Manual VS-2EGN

Vil. CIRCUIT DESCRIPTION
Iscanning
lines)
Line
So
‘
~
Subcarrier]
,,
at
eT
und
Video
Colour
Modulation
|
Phase
of
Burst
TV
system
iyith
respec
ay
TV-CH
frequency
spectrum
Modulation}
|
Modulation
System
aed
system
|
With
respect
to
B-Y
:
fp
fs
Br
B
(ur)
Picture
carrier
Sound
corrier
G
O75
0
5.5
MHz
G G|
PAL
|
4.433619
g
(UHF)
3
4
2
a
Sry
¥) se
H
eae
H
H
s
|#
(UHF)
1.25
°
5.5
MHz
g
625/50
15,625
FM
4
g
|
Pohas
ke
[ash
=
Ele,
Go
|
Sn
3
[sf/s/s/sfs
a
board
a
ee)
I I
I
g
2
1250
6.0MHz
3
4
g
2
a
=
2|
2/88]
3
D
D
s
(VHF)
&
075
0
6.5
MHz
K K
(UHF)
Positive
B
for:
G
B
AM
BY
SECAM
_dhoe2s
FM
No
burst
125.0
6.5MHz
®
har
NEGATIVE
15,750
Sane
M
525/60
|
8M
64
FM
}——=/M)_Nrsc
|
3.579545)
7°)
—180°
(Colour)
as
PAL
0.75
0
4.5MHz
Fig.
7-1
World
TV
Systems
and
Colour
Systems
1,
GENERAL
11
WORLD
TELEVISION
AND
COLOUR
SYSTEMS
eT
Re
m i
The
VS-2EGN
is
capable
of
recording
and
playback
of
Refer
to
Fig.
7-1.
television
signals
shown
below,
and
is
a
high
grade multi-
For
example,
in
the
case
of
SECAM
B/G
which
is
call-
function model.
ed
Middle
East
SECAM,
monochromatic
signals
follow
@
Recording/playback
of
PAL
BG
the
CCIR
system,
while colour
signals
are
of
the
SECAM
©®
Recording/playback
of
SECAM
BG
system.
©
Recording/playback
of
NTSC
4.43
(line
video
re-
cording
only)
@
Recording/playback
of
NTSC
3.58
(line
video
re-
cording
only)
©
Playback
of
SECAM
L
At
present,
there
are
various
television
systems
in
the
world.
Television
signals
which
can
be
recorded
or re-
produced
by
the
VS-2EGN
and
television
systems in
the
world
are
described
below.
‘Service
Manual
VS-2EGN

1-2 RADIO FREQUENCY HEAD OF VS-2
VS-2 DEMODULATOR
Receivable broad | VIDEO Receivable Broadcast
cast system |IF channels Demodulated signal
Model aaa Country
OUND
IF] VAF-L | VHe- | UHP Video Sound
(Mtn)
EG BIGPAL | 38.9 va B/G PAL Germany, Singapore
EGN | B/GSECAM oe aaal 24 | S12] 21-69 | seca Middle East Country
1 PAL 39.5 UK.
oe (HF only) 335 | 7 So) /Ine? | | th PAL Hong Kong
B/G PAL Mi~M10 B/G PAL .
EO B/G SECAM BG r Fer 5~12 | 21~69 | B/G Fake a
(CATV) : UI~U10 SECAM
B/G PAL :
EA ahora e685 o~s | SA~11 | 21~69 | BIG AM || ee ada
31.375 SEEM a
TPAL
38.9
-
ES | yur g VPA) Seg | ~~ | Avtd | zion | rPAL South-Africa
LSECAM
ao . bs Wide video
s L SECAM see on nears France
33, compared to
BIG
Fig. 7-2. VS-2 Demodulator
VS-2 RE Convertor
Moaer | Television isgicie SbeC airs Output | Video modu-
system channel | lation polarity
‘ cus
EA B VHF cH4
° +55 ile NEGATIVE ot
EG ‘ cH30
EO é DAF ~39
BGN sts variable |
$
EK
;
cH30
ES WHE: variable
3 5.596
BosiTVe
- | cxs0
s L ue ~39
5 65 | variable
Fig. 7-4 RF Converter Types for VS-2
As might be known from Fig. 7-1, the frequency spec-
trum, etc. of the television channel vary from TV system
to TV system. Accordingly, the tuner unit of the video
cassette recorder (VCR) which receives TV broadcasts
is classified as shown in Fig. 7-2 according to the model
code letters.
VS-2EGN has a built-in tuner for Model EG.
Fig. 7-3 shows the types of AKAI VTR available and the
transmission channels used in major countries.
The types of RF converter are classified as shown in
Fig. 7-4, which shows that the RF converter for the G
system is used for the VS-2EGN. This type of RF con-
verter is also used for models EG and EO.
12
2
g 2. 8 Z 2
B < a y
S a Zz
eo
Fd
4
S
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g 318 ee
oO = st >. 2 st st
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2
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ba ate 8
a) | ]* aye
& ° is)
=
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q|
x €
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ra a
2/8 & 3
Els
8 8
3
g
a le
a «| a
ey = - a a o “ a
Slo elo lel Slel ale) ele 3 Ss Ser 8
g| éle Els) ele ele] ele éle Is} le Ele) Sle
2
3
3s Ss 8] [s 3 3 ics 3
S S-St4s > 3 S s or
FY 23! ls = Fs = Es Fs
@ (gz |e [8 FA z |
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BB)
|e
& = z
FA
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S eye =
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2. -
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=
7
a
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g
500 600 700 800 900
Frequency (MHz)
400
300
Fig. 7-3. Types of AKAI VTR available and Transmission
200
100
20
Channels used in Major Countries
UHF-
‘VHF:

1-3. RECORDING/PLAYBACK FUNCTION OF VS-2EGN
Signal Recorded on tape
Recordable Video Signal a Playback Video
(With built-in tuner) Colour |, Signal
Frequency spectrum on tape proce gnal
“ Syne White CH-1 no
4 os c tip peak change
PAL
CH-2
extra
B/G 90° lag
° 5 MHz | O 0.627 3.8 4.8 MHz | every 1H ° 3 443MHz
c —M
fos son i FM CH-1 fos for
B/G Both no
0
5
MHz
|
0.664
3:8
48
MHz
|
change
° 3
MHz
foe 2 4,25MHz O81 fos | 4.25MHz
for : 4.40625 MHz for ° 4.40625MHz
(Through Line input)
4.43 CH-1 no
PAL
c c
change
B/G CH-2 extra
T 90° lai
HT | o Smuz | 0627 Be 48M | veyin | O 3 4,43MHz
Cc FM
fos for FM CH-1 fos for
SECAM | | | eu CH.2
B/G 3 t Both no
ce) 0.66 3.8 4,8 MHZ ° 3 MHz
fos : 4.25MHz 0.81 change fos © 4,.25MHz
for: 4.40625MHz os for : 4.40625 MHz
FM foe for
SECAM
L Recordable
°
fos > 4,25MHz
for : 4,40625MHz
CH-1 extra
358 90° advance
NTSC every 1H
| | / FM 3.58CH-2
°
° 4.2 Miz 0.629 34 44 MHz | extra 90° lag) 3 3.58 MHz
BOS every 1H
4143
NTSC ¢
0 MHz co) 3 4:43
MHz
Fig. 7-5 Recording/Playback Function of VS-2 EGN
Service Manual VS-2EGN

Refer to Fig. 7-5 Recording/Playback Function of VS-2
Recordable TV signals from built-in tuner
PAL B/G
SECAM B/G
Recordable TV signals from line input
PAL B/G/H/I
SECAM B/G (Middle East SECAM)
SECAM L (French SECAM)
NTSC 3.58 (standard NTSC)
NTSC 4.43 (modified NTSC)
1-4 SELECTION OF SIGNAL SYSTEM
As shown in Fig. 7-6, the operation panel of Model
VS-2EGN has an LED display unit (AUTO: green,
the rest: red), the there is a SYSTEM selector switch
below it. The SYSTEM switch permits manual system
selection.
Normally, reset is effected at Function-ON, and the
system selects the AUTO mode, which is detected by a
microcomputer and displayed. Accordingly, the SYS-
TEM switch is not used.
1-4-1 SYSTEM DISPLAY IN AUTO MODE
(Recording Electronic-to-Electronic (EE) Mode)
The SECAM L signal from the line input is recorded
as a SECAM B/G signal on the tape (system employing
count down of the SECAM colour signal similar to the
PAL system operation),
NTSC 4.43 signal is recorded on the tape as an NTSC
3.58 signal.
Playback signals vary from each other, and a 3-system or
a S-system television is required. The television should
be set so that the system display at the front of VS-2
EGN becomes the same mode as the displayed signal.
For details, refer to I]. Operating Procedure.
o
Cat 8/6
Ostcam 6/6
Ontsc 4.43
CISECAM L
Onrsc 3.58
SYSTEM
Fig. 7-6 System Display Unit
INPUT
LED VIDEO] PAL SECAM B/G | NTSC 4.43 | SECAML | NTSC 3.58
AUTO e e e e e
PAL B/G °
SECAM B/G e °
NTSC 4.43 e
SECAML - = o NOTE 1 -
NTSC 3.58 e
NOTES:
1.
Since
the
SECAM
L
signal
is
recorded
on
the
tape
as
a
SECAM
B/G
signal,
SECAM.
B/G
indicator
lights
in
the
LED
display
unit.
2.
When
there
is no
input
video
signal,
the
AUTO
indicator
alone lights.
(Playback Mode)
TAPE
PAL SECAM B/G. NTSC SECAM L
LED
AUTO e e e e
PAL B/G
SECAM B/G e
NTSC 4.43 = = = =
NOTE 1
SECAM L °
NTSC 3.58 e
NOTE: 1. When it is desired that signals are reproduced in NTSC 4.43, use the manual operation procedure.
14
‘Service Manual VS-2EGN

——
1-4-2 SYSTEM DISPLAY IN MANUAL MODE
For selecting the system manually, press the SYSTEM
switch the appropriate number of times until the desired
system is selected.
(Recording EE Mode)
No. of 4g] Function | 1sttime | 2nd time | 3rd time | 4th time | Sth time | 6th time
LED. ON
AUTO
e e
PALB/G
.
nore
s
SECAM
B/G
e
NOTE
2
NTSC
4.43
e
SECAM
L
NOTE1
=
=
=
=
=
NTSC 3.58 e
NOTES:
1.
SECAM
L
cannot
be
selected
in
the
Recording
EE
mode.
2.
When
all
LEDs
are
OFF,
the
mode
is
625
lines/50
Hz
monochromatic
mode.
3.
At
the
6th
time,
the
LED
display
returns
to
AUTO.
However,
when
there
is
no
video
input
to
the
VCR,
‘AUTO’
does
not
light.
The
LED
display
lights
a
colour
video
signal
is
connected.
(Playback Mode)
No, of
times
LED
AUTO
e e
NOTE 2
PALB/G
SECAM B/G
NTSC 4.43
SECAM
L
e
NTSC 3.58
eee Ist time |2nd time | 3rd time | 4th time | 5th time | 6th time | 7th time
NOTE 1
NOTES:
1.
When
all
LEDs
are
OFF,
the
mode
is
625
lines/50
Hz
monochromatic
mode.
2.
At
the
7th
time,
the
LED
display
returns
to
AUTO.
Since
a
video
signal
is
always
present
at
the
video
judge
(VJ)
output
during
playback,
the
LED
display
does
not
go
off.
1-5 VIDEO PRESENT/ABSENT JUDGEMENT
[
PB ON
Tuner receiving no signal picture
1
P.B Picture
Loading 1 2-6 sec
time
Fig. 7-7
In VS-2 EG/EO/EX/ES/EA/S, it is so controlled that
even when no wanted video signal is present, a video
signal is made to be present in the CUE/REVIEW mode
of playback only. Accordingly, at the time of CUE/
REVIEW playback of unrecorded tape, etc., a noise pic-
ture appears. On the other hand, no noise picture ap-
pears during normal playback or in the recording E-E
‘Service Manual VS-2EGN
mode, since switching to the internal oscillator takes
place when no video signal is present.
In VS-2EGN, no video judgement is performed in any
of the playback modes including CUE/REVIEW. That
is, control is exercised to ensure an always video signal
present condition. For this reason, the following special
picture changes occur.
15

In the cases of tuner reception (when the converter is
not connected to the VIDEO LINE IN) and no signal.
1) With no signal, the E-E picture is a gray picture from
the internal oscillator.
2) When the PB button is depressed, a tuner recep-
tion signal appears regardless of whether or not a pic-
ture is received. *1
3) The condition of 2) continues until the end of load-
ing and in addition for about 2.6 seconds, and then the
TV display is changed to the playback signal picture.
2. VS2-EGN VIDEO CIRCUIT OPERATION
VS-2EGN can perform the recording and playback of
the following signals.
1) Recording and playback of PAL B/G (from Built-in
Tuner to RF OUT)
2) Recording and playback of SECAM B/G (from Built-
in Tuner to RF OUT)
3) Recording and playback of NTSC 3.58M (from Line
in to Line Out)
4) Recording and playback of NTSC 4.43M (from Line
in to Line Out)
5) Playback of SECAM L (to LINE OUT)
Operation of the above five systems will now be des-
cribed. Since the systems differ in the filter characteris-
tics, PAL is mainly described, for the luminance system
section, and for other sections only points differing from
PAL are described.
The chrominance (CHROMA) circuit is described by
dividing it into the following four sections according to
the nature of its signals.
1) PAL B/G and NTSC 4.43 recording and playback
2) SECAM B/G recording and playback
3) NTSC 3.58
4) SECAM L playback
2-1 LUMINANCE (Y) RECORDING AND PLAYBACK
2-1-1 E-E SYSTEM (PLEASE REFER TO THE VIDEO.
SCHEMATIC)
A PAL B/G or SECAM B/G signal from the tuner (de-
modulator) or alternatively a video signal from LINE IN
is terminated at R1 (75), fed to VR-11 (E-E level)
for E-Elevel adjustment and fed to VIDEO AMP IC6
(HA11703) pin O, and output from pin . Quasi
V pulse (VP) is added by TR32 only while in the trick-
play, ie., CUE, REVIEW, and PB/PAUSE. Then, the
signal enters pin and is amplified. Next, the signal is
output from pin , and enters IC5 (HD14053BP) pin
©. Since the video signal is present and 12 VJ line of
the video judge (VJ) circuit in the servo circuit is ‘H’, the
signal is output to pin and then the character signal
is added at TR8 by the output Video on Word (VOW)
from the mi-com of the operation PC board. Now, the
video signal is output to LINE VIDEO OUT via TR2,
and it is fed to the RF converter from the VID terminal
through RL2 (LCB-56) and TR6. In summary, this sig-
nal flow represents the E-E system.
16
‘Service Manual VS-2EGN
*1: In the models other than VS-2EGN, 1) con-
tinues to the part of 2), but in Model EGN, the
PB 12V control line is used to control all play-
back modes. Since the PB 12V is output con-
currently with the depression of the PB but-
ton, the condition 2) appears.
2-1-2 RECORDING SYSTEM
In accordance with the description of the E-E system
in Section 2-1-1, the video signal is applied to IC5 (HD
14053BP) pin , and the character-added video is
applied to pin (2). The signal from pin (1) is output
through ICS output pin (©) at the normal time, ie.,
when pin (©) is ‘H’, and this output signal is fed to the
video head.
However, during the period. when INS LINE is kept ‘H’
by the mi-com of the operation PC board, pin is
kept at ‘L’ via the converter TR29, and the input from
pin @ is output to pin ®. That is, the character-
added video signal is supplied to the video head. ICS pin
@® output is branched to the LPF consisting of FL3,
and the LPF consisting of FL5. The —3 dB point of FL3
is 3.0 MHz, and is 3.3 MHz for FLS.
In the state where a PAL (B/G) or SECAM (B/G) signal
is being recorded, ICS pin is at ‘H’ level. Since pin
is connected to NT-L, only the luminance com-
ponent of the video signal which has passed through the
LPF is output to pi 3.
The output of pin (4) is supplied to IC1 (AN6310) pin
@), and is output to pin @3). During that time, the sig-
nal is subjected to AGC (automatic gain control), and
the deviation (1.0 MHz) of the frequency modulation
circuit in the next-stage is determined by VR8 located
between pins and ©.
The output of the VIDEO AMP circuit (pin @® — pin
) passes through the non-linear emphasis circuit.
The amount of emphasis is determined by TR12 and
TR16 when there is an NTSC signal. Then, the signal
enters pin 48 and is subjected to frequency modu-
lation. Since TR13 connected to pins @®/ @ be-
comes ON in the modes other than NTSC, the FM
carrier frequency is changed.
Dark Clip VR7 is connected to pin (2), while White
Clip VRS is connected to pin (Q). The frequencies of
White Clip, Dark Clip, and Deviation are as follows:
Mode} PAL B/G, SECAM B/G | 4.43, 3.58 NTSC
WHITE CLIP 5.4 MHz 5.0 MHz
PEAK WHITE 4.8 MHz 4.4 MHz
SYNC TIP 3.8 MHz 3.4 MHz
DARK CLIP 3.4 MHz 3.0 MHz

The frequency-modulated Y signal (FMY) from IC1 pin
(©) is directed to pass through the HPF consisting of FL1
(1.4 MHz at —3 dB point) so as to prevent interference
with the low frequency converted CHROMA (mentioned
later). Thereafter, the signal is controlled at VR4 (Y
REC LEVEL), mixed with the low frequency converted
CHROMA, passed through the REC Signal Inter-Board
Connection to the Audio/Pre P.C Board, fed to the PRE
AMP circuit, and supplied to the video head through the
emitter follower (TR10) and the constant current buffer
(TR8/9).
Since TR5 and TR6 are grounded by REC 12V during
recording, a closed circuit of REC current is formed via
R43, and VIDEO data is recorded on the tape.
2-1-3 PB SYSTEM
Since TR4 of the pre-amp circuit goes ON during play-
back, the PB VIDEO signals (FMY + Low Frequency
Converted Chroma) from the video heads 1 and 2 are
1) DROP OUT Pulse Generator (Refer to Fig. 7-8)
os
EEI2V
R58 100K
1c20)
At the time of a drop-out occurs, IC2 pin (0) becomes
‘L’, causing 1C3 (wH741TC) pin G) to become ‘L’.
Since C46 (1uF/S5OV) has only just started to discharge
pin @ does not become ‘L’. That is, the output is ‘L’.
D3 is for operation stop in the E-E mode.
The output of IC2 pin () is fed to the double limiter
circuit in which the signal is divided into two.
First it is directed to the HPF composed of C48, R62,
and C47, amplified at TR7, phase corrected at C39 and
R37, amplified at TR15, and fed to IC4 (TA7060AP)
pin @ . The signal is amplitude-limited at the 1st limit-
et between pin (1) and pin (4), and then applied to the
emitter of TR18.
Secondly, the output of IC2 pin ® is directed to the
LPF (4 MHz at —3 dB point) composed of R80 and
C57, and applied to the base of TR18. At the collector,
this signal appears, mixed with the first signal which is
applied to the emitter.
After being phase-corrected at TR9, L10, and R47, the
‘Service Manual VS-2EGN_
supplied to IC2 (AN6320N) pins@)and(5) After going
through pins 3) /G), PB VIDEO signals of CH-1 and
CH-2 are selected by the Amplifier Switching Pulse
which connects them to pins and ©, after the
overlap portions have been cut off. The outputs from
pins and (9) are mixed on the way to pin a, and
the mixture flows to pin () after going through the
MIX AMP, and then to the video PC board as a PB PRE
OUT through the emitter follower (TR7). On the video
board, the PB signal from the pre-amp is directed
through the HPF (1.4 MHz at —3 dB point) consisting of
C1, 5,6, R10, 11, and L1. Only FMY is extracted there,
fed to the 5.8 MHz peaking circuit composed of L35,
C203, and TR3, subjected to the phase correction at
C15, 16 and L6, fed to pin (3 of IC2 (HA11718) sub-
jected to AGC; and then output from pin () of IC2.
When there is a drop-out, the signal 1H earlier is output
from pin () and supplied to pin (} by DL1 (64 us
delay).
1
see = | THRESHOLD
! I i
© ‘
Fig. 7-8 DROP OUT Pulse Generator
signal is fed to IC6 (HA11703) pin (4) via the emitter
follower of TR39. After being amplitude-limited and
FM-demodulated on the way from pin) to pin@) the
signal is directed through the respective filters of FL8
(PAL), FL6, 7 (NTSC), and FL9, 10 (SECAM), and fed
to IC7 (HD14066BP) pins, @), Now, if both con-
trol signal lines 3N-H and 3L-H from the servo circuit are
‘L’ (PAL mode), the signal passes from IC7 pin (1) to
pin (), is directed to the non-linear de-emphasis circuit
composed of TR34, L20, C91, D8, and D9, phase cor-
rected at L11 and C102, then fed to IC6 pins @ and
®, and output from pin ©.
PB CHROMA is supplied to pin ® and mixed there.
The output of pin (16) passes through VP ADD of TR32.
17