Teac A-4010GSL User manual

SALES OFFICE:
TEAC HONGKONG LIMITED
A-4010GSL
STEREO
TAPE
DECK
SERVICE
MANUAL
U.S.
DISTRIBUTOR:
TEAC
CORPORATION
OF
AlERICA
TEAC
CORPORATION
;
7733
TELEGRAPH
ROAD
SHINJUKU
BUILDING
One
8-1,
NISHI-SHINJUKU,
SHINJUKU,
TOKY
S.A.
one
as
pee
EUROPEAN
DISTRIBUTOR:
TEAC
EUROPE
N.
8.
MELBOURNE
PLAZA,
33
QUEEN'S
ROAD
C.
ev
LANG
45-47,
AMSTEIDAM-W.
2,
MAIN OFFICE:
HONG KONG Ee]
PRINTED IN JAPAN, 072° S$ 005
MT4014E100

If
adjustments
or
repair
procedures
are
not
clear
or
seem
diffi-
cult
to
accomplish
or
should
you
desire
more
detailed
technical
information,
please
contact
your
nearest
TEAC
dealer,
TEAC
Corpo-
ration
or
affiliated
corporations
,
address's
of
which
are
printed
in
this
manual.
WONAMNPWN-
This
service
manual
provides
adjustment
and
alignment
procedures,
schematic
diagram
and
parts
replacement
information
and
the
prop-
er
procedures
for
obtaining
necessary
repair
parts.
SCOPE
TABLE
OF
CONTENTS
SL
&
GSL
FUNCT
IONAL-COMPARISON
CHART
SERVICE
DATA
TEST
EQUIPMENT
PARTIAL
DISASSEMBLY
HEADS
ALIGNMENT
-MECHANICAL-
MEASUREMENT
AND
ADJUSTMENT
-MECHANICAL
-
MEASUREMENT
AND
ADJUSTMENT
-ELECTRICAL-
PREVENTIVE
MAINTENANCE
TROUBLE
SHOOTING
“WARRANTY
AND
.SHIPPING
INSTRUCTIONS
EXPLODED
VIEW
AND
PARTS
LIST
PRINTED
CIRCUIT
BOARD
AND
PARTS
LIST
SCHEMATIC
DIAGRAM
MANUAL
CHANGE
SHEET

GENERAL
DESCRIPTION
The
TEAC
A-4010GSL
is
a
two
speed,
four
heads
(Forward;
erase,
record,
playback.
Reverse;
playback),
three
motors,
solenoid
operated,
quarter-track
stereo
open
reel
tape
deck
with
automatic
reversing
during
playback.
The
A-4010GSL
is
also
designed
for
LOW
NOISE/HIGH OUTPUT tapes.
The
TEAC
A-4010GSL
is
a
modernized
version
of
the
A-4010SL.
The
electronics
section
and
deck
mechanism
are
highly
similar
to
the
preceding
model.
Primary
differences
are
shown
below.

1ECHANICAL
Heads:
Tape Width:
Tape Speed:
Motors:
Wow and Flutter:
Fast Winding Time:
Operating Position:
Power Requirements:
Weight:
ELECTRICAL
Transistors:
Diodes:
Frequency Response:
Equalization:
Minimum Input:
1 SERVICE DATA
Four
track
2
channel
stereophonic.
Erase,
1.8k2/100kHz, erase current approx. 30mA
Record,
100Q/1kHz,
bias
current
approx.
2mA
Playback,
3kQ/1kHz
-53dB
se
Standard 1/4inch tape
3-3/4ips and 7-1/2ips (+1.0%)
4/8-pole
dual
speed
hysteresis
synchronous
motor for capstan drive.
6-pole
eddy
current
motors
for
reel
drive.
0.07% at 7-1/2ips.
0.09% at 3-3/4ips.
Wow
and
flutter
measured
according
to
weighted
NAB
standard
using
TEAC
flutter
free
tape.
Approx.
100
second
or
less
for
1,200
feet.
Horizontal or vertical.
100/117/200/220
or
100/117/200/240V
AC
(US
Model,
117V
60Hz
only)
50/60Hz
110W
max.
20.5kg (45.2 lbs)
2SA494(Y) x2
2SC971(Y) x2
2SC732(BL) x8
28C733(Y¥) x12
$1B01-06 x12
$1B02-01 xl
Refer to frequency response limit
NAB equalization
7-1/2ips 3,180usec. + 50usec.
3-3/4ips 3,180usec. + 90ysec.
MIC: Input impedance 30k2
70dB/6002
LINE: ~18dB/100k2

Maximum
Output:
LINE:
Approx.
-2dB/10k2
or
more
HEADPHONE:
-24dB/82
Bias
Frequency:
100kHz
push-pull
oscillator
Signal
to
Noise
Ratio:
50dB
or
more,
peak
record
level
to
unweighted
noise
Cross
Talk
Rejection:
40dB
channel
to
channel
at
1kHz
35dB
adjacent
track
at
100Hz
Erase
Efficiency:
7OdB
or
more
at
7-1/2ips
:
A
These
specifications
are
indispensible
information
and
are
required
to
service
the
equipment
properly.
They
may
differ
slightly
from
those
printed
in
the
advertising
brochures
or
the
operation
manual.
Fig. 1-1 Dimensions

2 TEST EQUIPMENT
For
proper
adjustment
and
measurement,
it
is
recommended
that
the
following
test
equipment
be
available:
FOR MECHANICAL MEASUREMENT
SPRING SCALE:
TEST TAPE:
FLUTTER METER:
DIGITAL FREQ. COUNTER:
TOOLS:
FOR ELECTRICAL MEASUREMENT
TEST TAPE:
EMPTY REEL:
TEST SET:
BAND PASS FILTER:
AC/DC VTVM:
RESISTOR:
OSCILLOSCOPE:
Use of the TEAC M-826A test set is
0v4 kilo-grams (08 1bs) #5086025000
0v300 grams(0V10 oz) #5086026000
TEAC YTT-2003 (7-1/2ips)
TEAC YTT-2002 (3-3/4ips)
Meguro Model MK665B (preferred) or
Sentinel FL-3D-1
Capable of 0 to 5kHz indication
General,
2mm nut driver #5086014000
Hex head, Allen wrench #5086021000
TEAC YTT-1003 for 7-1/2ips
TEAC YTT-1002 for 3-3/4ips
SCOTCH 203 and 150 for recording test
TEAC RE~702 (2" hub)
TEAC RE-701 (4" hub)
TEAC M-826A test set
TEAC M-206A (1kHz)
General purpose
Non inductive type 82/1W
General purpose
recommended. This set incorporates a LEVEL
METER, Audio Oscillator, Channel Selecting
Switch, Variable Attenuator, Monitor Speaker
and Cables.
TEAC M-826A measures the RMS value of the
Voltage
(0
dB=0.775V).
Characteristics
of
this test set are similar to the standard
VU-meter.
TEAC Test Set (M-826A)

a

3 PARTIAL DISASSEMBLY
TAPE
TRANSPORT
REMOVAL
(WITH
FRONT
PANEL
INSTALLED)
-
Lay
the
unit
face
down
on
a
soft
mat.
- With rear cover removed, loosen and
remove three screws at rear sides of
chassis. ae
-
Carefully
slide
transport
from
wooden
case.
AMPLIFIER REMOVAL
~
Remove
four
screws
from
amplifier
front
panel.
-
Slide
amplifier
forward,
remove
four
screws
from
amplifier
cover,
remove
cover.
-
Disconnect
the
cables
connecting
the
tape
transport
and
amplifier.
NOTE:
Edge
connectors
are
held
in
PC
board
by
two
retaining
nuts.
-
To
reinstall
the
amplifier,
reverse
the
procedure,
be
sure
to
reconnect
the
cables.
FACE PLATE REMOVAL
-
Place
the
unit
in
horizontal
position.
-
Pull
off the
pinch
roller
and
unscrew
capstan
dust
cap.
—
Remove
head
assembly
cover
after
re-
moving
mounting
screw
on
top
of
cover.
-
Remove
retaining
screw
on
left
tension
arm
and
lift
tension
arm
upward.
~
Loosen
and
remove
the
reel
height
ad-
justment
screw
in
each
reel
turntable.
~ Lift off the reel tables.
—
Remove
8
small
Phillips
screws
from
the
front
panel
(1
at
each
corner,
1
above
and
below
each
reel
motor).
Front
panel
may
now
be
removed.
~
Reverse
the
procedure
for
reassembly.
Fig. 3-1
Unit Disassembly

REEL HEIGHT ADJUSTMENT
NOTE: Reel height adjustment is required only if a motor has been
replaced or when the tape rubs excessively against the reel flanges.
Load unit with tape (standardized and start the tape. Adjust by
turning the screw in the reel table until the tape does not rub
against the reel flanges.
REEL TABLE ASSY REPLACEMENT
- Remove reel table by loosing the reel height adjustment screw.
- Reel table will slide off upward.
~ Remove the two allen screws at lower end of brake drum.
- Pull out the brake drum in the direction of the motor shaft.
~ Reverse: the procedure for reassembly.
~ Position the brake drum from the edge of the brake band as shown.
REEL HEIGHT
REEL TABLE ASSY
9339
M-O333
Fig. 3-2 Reel Table Assy Replacement
CAPSTAN MOTOR REPLACEMENT
- Slide out the capstan belt.
- Loosen the two set screws on pulley
and lift off pulley.
- Unsolder the six wires connecting
the capstan motor.
-
Remove
four
screws
located
around
capstan
shaft
on
front
panel,
tak-
ing
care
that
the
motor
does
not
drop
onto
other
components.
- Reinstall by reversing above
procedure.
-
Adjust
capstan
belt
tension
by
loos-
ening
the
four
screws
on
the
motor,
position
motor
for
proper
belt
ten-
sion,
then
re-tighten
screws.
- Apply a drop of LOCTITE on the
screws
when
adjustment
is
complete.
Fig.
3-3
Capstan
Motor
Wiring
TAPE SPEED Sw
AC 100V

CAPSTAN
CAPSTAN
ASSEMBLY
~
Remove
rear
cover,
remove
capstan
belt.
~
Remove
the
four
screws
holding
capstan
base(casting)
in
place.
-
Remove
the
three
screws
in
capstan
assembly.
-
Gently
pull
or
fold
capstan
base
forward
until
enough
clearance
is
obtained
to
remove
the
capstan
assembly.
CAUTION:
Do
not
exert
excessive
force,
a
gentle
pressure
should
suffice.
~
Loosen
the
two
setscrews
(HEX
HEAD)
on
rear
of
flywheel,
pull
out
the capstan assembly.
-
To
reinstall
capstan
assembly,
reverse
above
procedures.
IMPORTANT:
A
clearance
of
0.02"
must
be
maintained
between
the
flywheel
and
capstan
assembly.
BELT REPLACEMENT
-~
Remove
the
rear
cover
and
the
capstan
thrust
plate.
-
Capstan
belt
can
be
taken
off
through
the
flywheel
and
transport
chassis, opening.
CAUTION:
When
installing
the
new
capstan
belt,
be
careful
not
to
stretch
it.
Do
not
allow
oil
or
grease
to
contact
the
cap-
stan
belt.
After
installing,
clean
it
with
TEAC
rubber
cleaner.
-
Capstan
belt
tension
adjustmnet
can
be
made
by
loosening
four
mounting
screws
and
moving
the
capstan
motor.
-
Apply
a
drop
of
LOCTITE
on
the
screws
when
the
adjustment
is
complete.
ones
Fig.
3-4
Capstan
Assembly
Replacement

INDIVIDUAL HEAD REPLACEMENT
-
Remove
head
housing
cover
by
loosening
screw
on
top
of
cover.
-
Remove
the
two
screws
which
retain
head
assembly
and
separate
the
head
assembly
from
the
chassis
to
allow
easy
replacement
of
the
head
(does
not
require
this
procedure
when
replacing
erase
head
or with face plate removed).
-
Replacement
of
head
is
done
by
using
a
2mm
nut
dirver
(TEAC
#5086014000).
By
removing
two
setnuts
each
head
can
be
taken
off
easily
(one
screw
for
erase
head).
Slots
provide
access
-
through
the
plate
to
these
setnuts.
CAUTION:
Do
not
touch
other
set
screws.
=
-
Note
the
position
of
the
wires
on
the
circuit
board
before
unsol-
dering.
-
Reverse
the
procedure
to
reinstall
the
new
head.
NOTE:
Replace
the
nuts
securing
the
new
head
to
the
plate.
Perform
head
alignment
before
operation.
Head
installation
mounting
provides
for
left
or
right
position.
After
reinstalling
head,
determine
proper
position
while
record-
ing
or
playing
back
a
tape.
I
@
\ 2
. ae
, . RECORD OR
PLAYBACK
ha
S
Fig. 3-5 Individual Head Replacement

4
HEAD
ALIGNMENT
'-~MECHANICAL-
ERASE
HEAD:
The
erase
head
pole
should
be
above
the
edge
of
a
threaded
tape
by
the
width
of
a
heavy
pencil
line.
Turn
the
three
screws
indicated
to
obtain
this
height.
RECORD
HEAD:
The
record
head
pole
should
be
above
the
edge
of
a
threaded
tape
by
the
width
of
a
thin
pencil
line.
Turn
the
three
screws
indicated
to
obtain
this
height.
IMPORTANT:
After
completing
the
height
adjustment
make
certain
head
surfaces
are
parallel
with
tape
guide
surfaces
when
viewed
from the side.
PLAYBACK
HEAD:
The
reverse
playback
head
pole
should
be
even
with
the
bottom
of
the
tape
and
the
forward
play
head
pole
should
be
even
with
the
top
of
the
tape.
NOTE:
Refer
to
details
below
for
the
preceding
alignments.
ERASE
RECORD
PLAYBACK
Lch
Rech
Lch
Reh
Lch
Reh
2 .
Zz €): HEIGTH ADJ
@: AZIMUTH ADJ
PLAYBACK
ERASE
REVERSE
RECORD
FORWARD
HEAD
HEAD
HEAD HEAD
Fig.
4-1
Mechanical
Head
Alignment

5
MEASUREMENT
AND
ADJUSTMENT
-MECHANICAL
-
PINCH ROLLER PRESSURE
Pinch
roller
pressure
is
supplied
by
pinch
roller
pressure
spring
only
and
it
is
therefore
most
important
that
the
solenoid
plunger
has
fully
bottomed
before
taking
pressure
measurement.
1.
Block
the
automatic
shut-off
arm
in
the
OW
position.-—
2.
Attach
a
suitable
spring
scale
to
the
pinch
roller
shaft.
3.
Place
the
unit
in
the
play
mode
(§Bor—a@)
and
holding
the
scale
as
illustrated,
slowly
draw
it
away
from
the
pinch
roller.
4.
Note
the
reading
on
the
spring
scale
at
the
instant
the
pinch
roller
stops
rotating.
;
5.
The
spring
scale
should
indicate
1.52.5
kg
(3.3%5.5
lbs).
6.
If
adjustment
is
necessary,
adjust
the
double
nuts
on
the
capstan
solenoid plunger.
PINCHROLLER
Vom
0-113
Fig.
5-1
Pressure
Measurement
Fig.
5-2
Pressure
Adjustment
Nuts
FLUTTER
&
TAPE
SPEED
MEASUREMENT
_
Flutter
should
be
measured
in
playback
mode
using
a
TEAC
flutter
free
tape
YTT-2003-2002.
Connect
test
equipment
to
unit
as
shown
in
the
figure.
Measurement
of
flutter
should
be
made
in
accordance
with
NAB
standards.
Values
obtained
with
different standards
or
equipment
can
not be compared.
Flutter
should
not
exceed.
7-1/2ips:
0.20%
3-3/4ips:
0.25%
The
tape
speed
should
be
measured
using
TEAC
flutter
free
tape,
model
YTT-2003-2002.
These
tapes
contain
a
highly
accurate
3
kHz
tone.
The
indicated
frequency
should
be
2985
“3015
kHz
for
all
speeds,
both
directions.
TEST UNIT
FREQ, COUNTER
M-0342
These
figures
apply
to
any
tape
position
and
direction
(such
as
full
take-up
reel,
full
Fig.
5-3
Flutter
&
Tape
Speed
supply
reel
or
about
mid
point).
Measurement

REEL MOTOR TORQUE
IMPORTANT:
Be
sure
the
full
required
line
voltage
is
applied
and
that
the
unit
is
set
up
for
proper
line
frequency.
Holdback
Tension
-Forward-
1.
Tape
or
block
the
automatic
shut-off
arm
in
the
ON
position.
2.
Place
an
empty
reel
RE-702
(2"
diameter
hub)
and
spring
scale
on
the
left
reel
table
as
shown
in
figure.
7
3.
Rotate
the
reel
table
clockwise
and
wind
several
turns
of
string
around
the
hub.
4.
Place
the
unit
in
the
forward
play
mode
(
Be).
5.
Pull
the
scale
away
from
the
reel
against
the
motor
torque
with
a
steady
smooth
motion.
”
6.
Note
the
spring
scale
reading
while
it
is
in
steady
motion.
The
spring
scale
reading
should
be
50°52
grams(torque:
2501260
g-cm).
7.
If
adjustment
is
required,
move
the
slider
of
R-6
(D)
until
cor-
rect
tension
is
obtained.
Holdback
Tension
-Reverse-
8.
Place
the
empty
reel
and
spring
scale
on
the
right
reel
table.
9.
Place
unit
in
the
reverse
play
(~@)
mode.
NOTE:
Rotate
the
reel
table
counter
clockwise.
10.
Repeat
above
steps
3,
5,
6
of
forward
holdback
tension
section.
11.
The
spring
scale
reading
should
be
5052
grams
(torque:
250260
g-cm).
12.
Adjust
the
slider
of
R-8
(B)
until
correct
holdback
tension
is
obtained.
CHASSIS
he df. ad
TT p nord cama
BNOYO!) dN 34V1:NOISNAl HOVS
TAKE UP TORQUE: BACK TENSION
TEAC
RE-702
7204-30
oval
[Prog
LEFT MOTOR
ein Geta
|
mea
@-
sINCREASE TORQUE DIRECTION D-tt-ll
Fig.
5-4
Torque
Measurement
Fig.
5-5
Tensioning
Resistor

Take-up Torque -Forward-
1.
NDF Wh
Take-up Torque -Reverse- os
ro
8.
9.
Place
an
empty
reel
RE
702
(4"
diameter
hub)
and
spring
scale
on
the
right
reel
table
(see
figure).
Place
the
unit
in
the
forward
play
(
Bm)
mode.
Allow
the
rotation
of
the
reel
to
draw
the
scale
toward
the
hub.
Hold
the
spring
scale
with
enough
force
to
allow
a
steady
reading.
It
should
be
60°64
grams
(torque:
300320
g-cm).
If
adjustment
is
required,
adjust
the
slider
of
R-8
(A).
Place
an
empty
reel
on
left
reel
table
and
depress
the
reverse
button ( =a).
Repeat
above
step
3,
4,
5
of
forward
take-up
torque
section.
If
adjustment
is
required,
adjust
the
slider
of
R-6
(C)
(60v64
grams).
Brake Torque
Brake
adjustments
are
made
with
no
power
applied
to
the
unit.
l.
2.
3.
Fig. 5-6 Brake Torque Measurement
Place
an
empty
4"
hub
reel
and
spring
scale
on
left
reel
table.
Wind
several
turns
of
string
counter
clockwise
around
the
hub
and
attach
a
suitable
spring
scale
to
the
free
end
of
the
string.
Pull
the
spring
scale
away
from
the
reel.
Take
a
reading
only
when
the
reel
is
in
steady
motion
since
the
force
required
to
overcome
static
friction
will
produce
a
false,
excessively
high
initial
reading.
The
reading
should
be
2607300
grams
(1,300%1,500
g-cm).
If
adjustment
is
required,
adjust
the
brake
adjusting
spring
arm
for
the
proper
brake
torque.
.
To
check
and
adjust
the
right
reel
brake
repeat
all
steps
as
de-
scribed
for
left
reel
with
the
exception
that
all
directions
of
rotation
are
clockwise.
Adjust
brake
adjusting
spring
arm
(right)
for
proper
brake
tension.
IMPORTANT:
The
difference
in
torques
between
the
right
and
left
brake
should
be
kept
within
10
grams
(50
g-cm).
. OS
>
Teac eae
nE-70t RE-7O1
Fig.
5-7
Brake
Adjustment
Arm

FAST WIND TIME
NOTE:
Clean
all
tape
guide
components
and
check
for
proper
AC
line
voltage.
Using
a
1,200
feet
tape
on
a
7"
reel,
the
fast
wind
time(fast
forward
or
fast
rewind)
should
be
100
seconds
or
less.

G
MEASUREMENT
ANID
A
—~ELECTRICAL—
GENERAL
NOTICE
Before
performing
any
maintenance
on
this
unit,
all
metal
parts
that
the
tape
will
come
into
contact
with
must
be
cleaned
and
demagnetized.
=
It
is
important
that
the
unit
is
set
for
the
proper
voltage
and
frequency
for
your
locality.
Standard
test
tapes-and
test
equipment
must
be
used
when
per-
forming
maintenance
to
insure
reliable
results.
Procedures
for
checks
and
adjustments,
unless
otherwise
indi-
cated,
are
for
the
left
channel
at
7-1/2ips.
The
same
pro7~
cedures
are
to
be
applied
to
the
right
channel
and
3-3/4ips
tape speed.
All
controls
mentioned
in
this
book
will
be
printed
in
bold
letters
and
will
be
exactly
as
they
appear
on
the
unit.
Double
designated
symbol
numbers
refer
to
left
channel/right
channel.
THD:
Third
harmonic
distortion.
Value
of
"dB"
in
the
text
refers
to
0dB=0.775V,
except
where
specified.
If
a
level
meter
or
an
AC
VTVM
calibrated
to
OdB
=1V
is
to
be
used,
appropriate
compensation
should
be
made
by
adding
approximately
+2
dB.
DJUSTMENT

PLAYBACK
PERFORMANCE
-24dB(8Q LOAD)
FORWARD + Sp
?
PB.FILTER
suieUT
PLAYBACK
HEAD
o
z
(out
PUT}
Bs
-848
REVERSE
>
oot
MONITOR
‘
VU
METER
Fig.
6-1
Simplifier
Diagram
—Playback-
aaa
vR107
vR205
-vr105
vR208
VR207
VR1O8
Fig.
6-2
Adjustable
Parts
Location
PLAYBACK
HEAD
AZIMUTH
ADJUSTMENT
Coarse
Adjustment
1.
Connect
a
level
meter
to
either
OUTPUT
jack.
2.
Thread
a
TEAC
test
tape
YTT-1003
on
the
unit.
3.
Depress
forward
button
(
pe)
and
play
the
15
kHz
test
tone
in
section
2
of
the
test
tape.
4.
Slowly
rotate
the
azimuth
screw(forward)
until
max.
indication
is
obtained
on
the
level
meter.
NOTE:
If
during
playback,
a
slight
pressure
on
the
heads
re-
sults
in
a
rise
of
the
reading
of
the
level
meter,
head
alignment
readjustments
should
be
accomplished.
Fine Adjustment
CAUTION:
After
coarse
adjustment,
do
not
make
large
corrections,
turn
azimuth
screw
1/4
turn
or
less.
5.
It
is
absolutely
essential
to
accomplish
the
coarse
adjustment
before
using
this
method
to
avoid
phase
errors
larger
than
45°
6.
Connect
the
test
equipment
as
shown
in
Fig.
6-7-
7.
Play
a
10
kHz
signal
and
adjust
the
azimuth
screw
until
the
oscil-
loscope
shows
that
the
signals
are
less
than
45°
in
phase.
8.
Secure
the
screw
with
a
drop
of
LOCTITE
and
apply
the
above
proce
dure
to
the
reverse
playback
head.

SPECIFIED OUTPUT LEVEL SET
NOTE:
Connect
a
10
kQ
load
to
the
OUTPUT
jacks
when
not
using
the
TEAC
M~826A
(0
dB
= 0.775V)
level
meter.
Unless
otherwise
specified,
the
EQ/LEVEL
switch
must
always
be
in
the
NORMAL
position
during
measurement
and
adjustment.
9.
Play
the
400
Hz
tone
in
section
1
of
the
test
tape.
This
tone
is
recorded
at
operating
reference
level
(1%
of
the
THD
level).
10.
Turn
the
OUTPUT
controls
full
clockwise,
and
adjust
VR-107/207
for
-2
dB
reading
on level
meter.
ll.
Then
turn
OUTPUT
controls(c.c.w.)
until
a
-8
dB
reading
is
obtained
on
the
level
meter.
:
NOTE:
If
equal
reading
cannot
be
obtained
in
step
10.
Readjust
VR-107/207
slightly.
NOTE:
This
is
the
specified
output
level
set.
Do
not
disturb
this
setting
until
the
remaining
adjustments
have
been
completed.
VU METER CALIBRATION -PLAYBACK-
12.
While
playing
the
400
Hz
tone(1%
THD)
in
section
1
of
the
test
tape,
adjust
VR-108/208
for
a
reading
of
0
VU
on
the
VU
meter.
FREQUENCY RESPONSE
13.
Play
the
test
tones
from
15
kHz
down
to
40
Hz.
(Recorded
at
10 dB
below
operating
reference
level.)
14.
Compare
the
readings
obtained
on
the
level
meter
with
the
response
limits given in figure below.
15.
In
case
of
any
deviation
in
the
response
curve,
check
head
azimuth
alignment,
clean
the
heads,
then
adjust
VR-105/205
for the
best
response.
NOTE:
7-1/2ips
tape
speed
must
be
used
for
frequency
response
checks
and
adjustments.
Do
not
attempt
VR-105/205
readjustments
at 3~3/4ips.
EQ/LEVEL switch check
-
While
playing
back
400
Hz
(operating
reference
level)
signal,
move
the
EQ/LEVEL
switch
from
HIGH
to
NORMAL
position.
The
VU
meter
should
decrease 3 dB.