Teac A-4070G User manual

TEAC
CORPORATION
ay
A-4070G
®
STEREO
TAPE
DECK
SERVICE
MANUAL
ALSO
APPLICABLE
40706
SALES
OFFICE:
SHINJUKU
BLDG,
1-8-1,
NISH-SHINJUKU,
TOKYO
PHONE:
(03)
34351531
TEAC
CORPORATION
OF
AMERICA
7733
TELEGRAPH
ROAD,
MONTEBELLO,
CALIFORNIA
90640
PHONE:
(213)
7269303
TEAC TONBAND-ANLAGEN
VERTRIEBS GmbH
6200
WIESBADEN-ERBENHEIM,
EGERSTRASSE
2,
WEST
GERMANY
PHONE:
(06121)
74225-2322
8
TEAC HONGKONG LIMITED
51031092 8B
ROOM
NO.
1105
MELBOURNE
PLAZA,
33
QUEEN'S
ROAD,
HONG
KONG
PHONE:
2:20
27
PRINTED IN JAPAN 045 O03

1 GENERAL DESCRIPTION
The TEAC A-4070G is a 2 channel, 4 track tape deck capable of both
bi-directional recording and playback, The A-4070G employs a three
motor mechanism, solenoid operated, with auto reverse in either
direction, automatic repeat and continuous play capability.
The basic design of the A-4070 is highly similar to that of the
A~4070G, therefore information in this service manual may be ap-
plied to the A-4070.
This service manual provides adjustment and alignment procedures,
schematic diagrams and parts replacement information and the prop-
er procedures for obtaining necessary repair parts.
If adjustments or repair procedures are not clear or seem difficult
to accomplish or should you desire more detailed technical informa-~
tion, please contact your nearest TEAC dealer, TEAC Corporation or
affiliated corporations, address's of which are printed in this
manual.
INDEX
1. GENERAL DESCRIPTION
2. SERVICE DATA
3. EQUIPMENT REQUIRED
4. PARTIAL DISASSEMBLY
5. HEAD ALIGNMENT -MECHANICAL-
6. MEASUREMENT AND ADJUSTMENT ~MECHANICAL-
7. MEASUREMENT AND ADJUSTMENT -ELECTRICAL~
8. PREVENTIVE MAINTENANCE
9. TROUBLE SHOOTING
10. PACKING FOR SHIPMENT
SCHEMATIC DIAGRAMS
PRINTED CIRCUIT BOARD AND PARTS LIST
EXPLODED VIEW AND PARTS LIST
MANUAL CHANGES

MECHANICAL
2 SERVICE DATA
Heads:
(Ferrite)
Tape Width:
Tape Speed:
Motors:
Wow and Flutter:
Fast Winding Time:
Operating Position:
Power Requirements:
Weight:
ELECTRICAL
Transistors:
Diodes:
Frequency Response:
Equalization:
Input:
Bias Frequency:
Signal to Noise Ratio:
Stereo Chan.
Cross Talk:
Erase Efficiency:
Separation:
Four track 2 channel stereophonic
Erase/Record combination head x2;
Erase section,
1.8k2/100kHz, erase current approx. 30mA
Record section,
95Q2/1kHz, bias current approx. 25mA
4.7k2/100kHz, signal current approx. 400Hz 200yA
Playback x2;
1.2kQ/1kHz -66dB
Standard 1/4 inch tape
7-1/2ips and 3-3/4ips (40.5%)
4/8-pole dual speed hysteresis synchronous
motor for capstan drive
Two 6-pole eddy current motors for reel drive
0.06% at 7-1/2ips
0.09% at 3-3/4ips
Wow and flutter measured according to weighted
NAB standard using TEAC test tape.
Approx. 120 seconds or less for 1200 feet
Horizontal or vertical
100/117/200/220/240V AC 50/60Hz 125W
51 lbs (23kg) net
2SC733BL x2 2SA494 x2
250733 x14 2SC971 x2
2SC1LOOOBL x12
FR2-02 x3 FR2-10 x2
SIBO2-B x1 FR2-08 x3
FR2-06 x7
Overall from recording INPUT to playback
OUTPUT using SCOTCH #203 tape
7-1/2ips, +3dB 30Hz v20kHz
3-3/4ips, +3dB 40Hzv10kHz
NAB equalization
7-1/2ips 50yu sec
MIC 0.3mV (-70dB)
LINE 0.1V (-18dB)
100kHz push-pull oscillator
7-1/2ips 48dB or higher
3-3/4ips 46dB or higher
at playback to unweighted noise
45dB channel to channel at 1kHz
35dB adjacent track at 100Hz
70dB or more at 7-1/2ips
3-3/4ips 90n sec
These specifications are indispensable information and are required
to service the equipment properly.
They may differ slightly from
those printed in the advertising brochures or the operation manual.

3 EQUIPMENT REQUIRED
FOR
MECHANICAL
MEASUREMENT
————————__________
eee
SPRING SCALE:
TEST TAPE:
FLUTTER METER:
DIGITAL FREQ. COUNTER:
TOOLS:
0.4 kilo-grams (08 lbs) #5086025000
0.300 grams (0°10 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 O to 5kHz indication
General,
2mm nut driver #5086014000
Hex head, allen wrench #5086021000
TEAC TEST TAPE
Fig. 3-l Spring Scale, and TEAC Test Tape
FOR ELECTRICAL MEASUREMENT
TEST TAPE:
EMPTY REEL:
TEST SET:
BAND PASS FILTER:
AC/DC VIVM:
RESISTOR:
OSCILLOSCOPE:
Fig. 3-2 TEAC M-826A
TEAC YTT-1003 for 7-1/2ips
TEAC YTT-1002 for 3-3/4ips
SCOTCH 203 and 150 for test recording
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
NOTE
Use of the TEAC M-826A test set is rec-
ommended. This set incorporates an AC
VTIVM, Audio Oscillator, Channel Select~
ing switch, Variable Attenuator, Monzitor
Speaker and Cables.
TEAC M-826A measures the RMS value of
the Voltage (OdB=0.775V). Characteristics
of this test set are similar to the stan-
dard VU-meter.

4 PARTIAL DISASSEMBLY
REMOVING THE EQUIPMENT FROM CASE
Case should only be removed to perform major maintenance.
1. Lay tape deck, face down on a soft
mat.
2. Remove the two (2} screws at the
top of the case, remove the four
(4) screws on rear of case.
Carefully lift case from mechanism.
7% (200mm)
=
Dimensions
173449 (456mm)
(awaon*%.s1 (wmgey) 2621

FRONT PANEL REMOVAL
I
ul & WN
6.
7.
Place the A-4070G on its back, with the front panel assy face up
and the bottom of the deck towards you.
Remove the head housing assy.
Remove both tape tension arms.
Remove knobs.
Remove the ten (10) cross-point screws from the front panels.
NOTE
Two screws are immediately above the tape head mechanism.
Lift off the control panel assy.
Lift off the front panel assy.
AMPLIFIER ASSEMBLY ACCESS
The A-4070G is equipped with a removable amplifier assembly. By
removing the six screws that secure the amplifier to the bottom of
the chassis, you can easily swing out the amplifier for maintenance.
Most of the replacement components are completely accessible. If
amplifier assy maintenance is necessary, follow these steps:
1.
2.
AMPLIFIER ASSEMBLY ACCESS
Complete all steps in front panel removal.
Remove six (6) cross-point screws from the sides of the bottom
panel.
NOTE
Three lower screws are holding the cover panel over the
PC boards. These need not be removed. Access slots are
provided.
Grasp the control shafts and gently swing the amplifier assy dow
towards you. Two screws on the lower sides act as a hinge for the
assy.
To re-~assemble, reverse the above procedure.
CAUTION
When closing the amplifier assy, closely observe the wires
leading to the right-channel VU meter lamp socket.

PLAYBACK HEAD REPLACEMENT
The playback heads have a detachable
shielded housing, see the exploded
view illustration for disassembly
instructions.
omm(
o- Ot
(6600
e-
@
M-0286
Fig. 4-1 Individual Heads
CAPSTAN MOTOR REMOVAL
1. With front panel removed, remove
4 capstan motor mounting screws.
2. Unsolder the 6 wires connecting
the capstan motor. (Carefully
note the wire locations and
color codes).
NOTE
After motor replacement, check
position of capstan pulley on
shaft for proper alignment with
belt guide.
REEL MOTOR REMOVAL
1. Disconnect oiling tubes at motor
housing.
2. Loosen 2 set screws securing the
reel table assembly, remove reel
table.
3. Remove the four screws securing
motor to chassis, unsolder the
six wires connecting the motor.
NOTE
Reel motor assemblies are mirror
images of each other, these as-—
semblies are not interchangeable.
Fig. 4-3 Reel Motor Removal

DISASSEMBLY OF CAPSTAN/HEAD MOUNT AREA
1.
2<
Remove the VU meter holder.
Remove four button head Philips screws securing the head base plate.
Base plate may now be lifted forward to accomplish belt replacement.
In order to replace the capstan assembly, the slide base assembly must
first be removed.
1.
2%
Remove the L & R lower head protectors. Remove pinch roller.
Remove lower screw and nylon inserts from slide base assembly.
(located below the pinch roller shaft housing).
. Disconnect slide base assembly coil spring.
. Remove the screw in one of the head PC board brackets, lift PC board
from bracket thus freeing the lifter spring bracket.
. Remove screw and nylon inserts from lifter spring bracket.
Slide base assembly may now be removed exposing the capstan assembly
mounting screws.
Fig. 4-4 Capstan Assy and Head Mount Removal

REEL MOTOR
C801 POWER TRANSFORMER
REEL MOTOR
K3
K2
Kl
K7
K6
K5
ee
K4
K8
Bo? ewpinions SY
FREQUENCY SELECTOR LEVER -~~
PULL 60Hz
FREQUENCY SELECTOR SWITCH -4
NOTE
K3 REV. RELAY R802 BACK TENSION
K2 REV. RELAY R803 TAPE 0.5 MIL (THIN)
Kl PLAY RELAY R801 TAKE-UP
K7 REPEAT SENSING RELAY K1l F. FWD RELAY
K6 REV. SENSING RELAY K10 SPEED RELAY
K5 FAST RELAY K12 MUTING RELAY
K4 DELAY RELAY
K8 SHUT OFF RELAY
TAPE TRANSPORT PARTS LOCATION
— REAR—
R803
R802
R801
Kil
K1O
K12
R804
C813
CAPSTAN MOTOR
C803/805
M-0284

5 HEAD ALIGNMENT —MECHANICAL—
NOTE
Head
alignment
is
adjusted
at
the
factory
to
very
critical
tol-
erances.
Normally
HEAD
ASSEMBLY
replacement
will
require
only
minor
alingments
or
adjustments.
Complete
readjustment
should
only
be
necessary
after
an
individual
head
is
replaced.
The adjustments are made as follows:
FORWARD SIDE
@ERASE/RECORD COMBINATION HEAD: The record head pole should be above
the
edge
of
a
threaded
tape
by
the
width
of
thin
pencil
line.
NOTE: Erase head should be heavy pencil line.
@PLAYBACK
HEAD:
The
playback
head
pole
should
be
even
with
the
top
of
a
threaded
tape.
e
e HEIGHT
ADJ . SCREW
e
m) e AZIMUTH
ADJ . SCREW
Fig. 5-1 Head Alignment and Adjustment sede Seco es oe |
M-0287
ERASE/RECORD PLAYBACK ERASE /RECORD
COMBINATION cabaeiea COMBINATION
REVERSE SIDE
@ERASE/RECORD COMBINATION HEAD: The record head pole should be bottom
the edge of a threaded tape by the width of thin pencil line.
NOTE: Erase head should be heavy pencil line.
@PLAYBACK HEAD: The pole of the playback head should be even with t he
bottom of a threaded tape.
NOTE
Azimuth adjustments are given in the section on MEASUREMENT AND
ADJUSTMENT -ELECTRICAL-

HEAD WIRING
Eo #
pas
x
=
S'8,
| { x x
L-CH R-CH ~—_L-CH R-CH
RECORD
ee
&
=
-
Q
>
2,
as
2 <i
Fs |
f f 1) i t
WY
oO
ina
ro}
<y “9, “2, <2, 62,
t
t
t
!
t
L-CH
R-CH
|
L~CH
R-CH
L-CH R-CH
RECORD PLAY BACK PLAY BACK
FORWARD REVERSE
------------5
NOTE: C__iCombination Head M-0292
The position of the wires on the
circuit board. Connect the new
head in the same manner.

6
MEASUREMENT
AND
ADJUSTMENT
—MECHANICAL
—
PINCH ROLLER PRESSURE ADJUSTMENT PROCEDURES
NOTE
Pinch roller pressure is supplied by pinch roller spring
arm only and it is most important that the solenoid plung-
er be fully bottomed before pressure measurement. Remove
knob and amplifier panel.
1. Block the shut-off arms in the on position.
2. Attach a suitable spring scale to the pinch roller shaft.
3. Place the unit in the PLAY mode, and holding the spring scale as
illustrated, slowly draw it away from the pinch roller.
4. Do not allow the string so rub against the pinch roller.
5. Note the reading on the spring scale at the instant the pinch roller
stops rotating.
6. The scale should indicate 2.0 +0.2 kg (5.0 1bs~5.6 lbs).
7. If adjustment is necessary, loosen the three screws on the capstan
solenoid and position the solenoid for optimum pressure.
8. Solenoid spring width should be approx. 11 mm.
INCREASE
DECREASE
jos
Timm
CAPSTAN
ral
theeed
PINCHROLLER
SPRING SCALE
3 SCREWS ose
REPOSITION SOLENOID TO OBTAIN
' Bais OPTIMUM PRESSURE
Fig. 6-1 Pressure Measurement and Adjustment Location

REEL
TORQUE
ADJUSTMENT
PROCEDURES
—————--—————_
"=
Voltage Specifications
Before
making
reel
torque
adjustments,
measure
the
voltages
as
outlined
below.
Voltages
are
measured
from
point
(A)
on
PC
board
#50482780
and
the
applicable
resistor
tap.
Place
the
unit
in
the
PLAY
mode.
A. R-801, TAKE-UP TORQUE. Voltage from point (A) to center tap of R-801
should read 54 +1V AC.
B. R-802, BACK TENSION. Voltage from point (A) to lower tap of I-802
should read 45 +1V AC. (Tape switch in REGULAR position.)
C. R-803, TAPE TENSION (0.5 mil THIN position). Voltage from point (A)
to R-802 lower tap should read 40 +1V AC with tape tension switch at
THIN position.
CONNECT VIVM
OR EQUIVALENT
METER
THIN
TAKE-UP BACK TENSION TAPE 0.5 MIL
Rsot
REAR
OF
TAPE
DECK
M-0282
#50482780
Rsol
C 803
“s, (A)
+o TEST POINT
~~
Caos
}
W
aby
D-OSI7
Fig. 6-2 Tension Resistor Voltage Measurements
and Operation Diagram

TAKE-UP TORQUE MECHANICAL CHECK
WN RF
Block the shut-off arms in the ON position.
Place
tape
tension
switch
in
REGULAR
position.
Place
an
empty
reel
(RE-701)
on
right
reel
table.
Rotate
the
reel
and
wind
several
turns
of
string
around
the
hub.
Attach
the
spring
scale
to
the
string,
depress
the
Bb»
button.
Allow
the
rotation
of
the
reel
to
slowly
draw
the
scale
toward
the
hub.
‘The
spring
scale
should
indicate
300
+20
g-cm
(4.2%4.6
oz~inch)
. Adjust R-801 as required.
BACK
TENSION
MECHANICAL
CHECK
————————
el
.0
0
Place
the
reel
and
spring
scale
on
the
left reel
table,
depress
the
B®
button.
Pull
the
scale
away
from
the
reel
against
the
mctor
torque
with
a smooth
steady
motion.
The
scale
should
indicate
230
+20
g-cm
(3.2%3.6
oz-inch).
. Adjust R-802 as required.
NOTE
Torque
and
back
tension
measurements
may
be
made
in
either
direction
(forward,
reverse)
of
play.
Fig. 6-3 Torque Measurement Forward and Reverse Side

BRAKE TORQUE ADJUSTMENT PROCEDURES
NOTE
The brake torque is actuated mechanically. Pressure is set by
the variable spring force. While making this measurement and
adjustment, be careful not to bend the brake bands. As brake
torque will change with cleaning, brake drums and brake shoes
should be cleaned only when absolutely necessary. If cleaning
is required, use TEAC cleaner TZ-251B only. After cleaning
operate the machine for some time before performing the below
procedures.
Brake torque adjustments are made with no power applied to the
unit.
Place an empty 4" hub reel on the left reel table, and fasten one
end of a 30" length of string to the reel anchor.
. Wind several turns of string counterclockwise around the hub and
attach a suitable spring scale to the free end of the string.
Pull the spring scale away from the reel, making sure that the
string does not rub the reel flanges.
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 1300 +100 g-cm (1620 oz~inch).
If adjustment is required, loosen the screw in the spring
mount and position the brake for optimum torque.
The adjustment of the right brake is the same, with the exception
that rotations are clockwise.
BRAKE BAND
MOUNT
M-0280
Fig. 6-4 Torque Measurement and Adjustment Location
IMPORTANT
The difference in torque between the right and left brake
should be kept within 50g-cm(0.7oz-inch).

LEFT RIGHT BRAKE TIMING
1. Block tension arms in ON position.
2. Depress <@ orp button, depress STOP key, observe that both
reel turntables stop at exactly the same instant. If they do
not, adjust the appropriate brake band spring mount as required.
(Refer to Fig. 6-4 Adjustment Location.)
BRAKE BAND CLEARANCE
1. With power off, manually depress the brake solenoid plunger,
brake band to drum clearance should be 1%2mm. Adjust to proper
clearance by repositioning the brake band mount.(Refer to Fig. 6-4.)
REEL
HEIGHT
ADJUSTMENT
———_———@
———_
cm
uo
Reel
height
adjustment
may
be
required
to
fit
reels
of
different
manufactures.
Adjustment
is
accomplished
by
FINE
ADJ.
screw
in
the
reel
turntable.
Reel
turntable
height
should
be
adjusted
using
standard
7"
reels.
With
a
tape
threaded
on
the
machine,
position
the
reel
height
for
smooth
tape
travel.
FINE ADJ. SCREW
TAPE SHOULD WIND
EVENLY ON REEL
COARSE ADJ-SET SCREWS
Fig. 6-5 Reel Height Adjustment

FLUTTER
TAPE SPEED
VOLTAGE
Flutter should be measured in playback mode using a TEAC flutter
free tape YTT-2003-2002 and Meguro model MK665B flutter meter.
Measurement of flutter should be made in accordance with NAB
standards.
Values obtained with different standards or equipment cannot be
compared.
Flutter should not exceed. 7-1/2ips: 0.15%
3-3/4ips: 0.20%
These figures apply to any tape position and direction(such as
full take-up reel, full supply reel or about mid point).
The tape speed should be measured
using TEAC flutter free tape, model
Y¥TT-2003:2002. These tapes contain
a highly accurate 3 kHz tone.
Connect a digital frequency counter
to either line OUTPUT jack.
The indicated frequency should be 3
kHz +0.5% for all speeds.
TEST UNIT
FLUTTER FREE TAPE
FREQ. COUNTER METER
Fig. 6-6 Test Equipment Set-Up
AND FREQUENCY CONVERSION
Voltage Conversion
The A-4070G may be set for 100, 117, 200, 220 and 240V AC, to
change the voltage unscrew the fuse in the center of the volt-
age selector plug, pull out the plug and reinsert it so that
the desired voltage shows in the cutout, reinstall fuse.
Fig. 6-7 Voltage and Frequency Conversion
Frequency Conversion
Frequency change is accomplished by means of the frequency
change knob on rear of unit
1. Thread a tape on machine.
2. Start deck in playback mode.
3. While deck is operating, gently pull out on knob for 60 Hz
operation, push in for 50 Hz operation.

7 MEASUREMENT AND ADJUSTMENT
—ELECTRICAL—
GENERAL NOTICE
Before performing maintenance on this
unit, thoroughly clean and demagnetize
the entire tape path.
It is important that the unit be set
to the proper voltage and frequency
for your locality.
TEAC specified standard test tapes and
test equipment must be used when per-
forming maintenance to insure reliable
results.
Procedures for checks and adjustments,
unless otherwise indicated, are for
the left channel at a tape speed of
7~1/2ips. The same procedures are to
be applied to the right channel and
again for both channels at 3-3/4ips,
and both directions,
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.
T HD : Third Harmonic Distortion.
Fig. 7-1
PLAYBACK PERFORMANCE ADJUSTMENTS
CH PB LEVEL PB METER LEVEL
“@REVERSE | FORWARD >
L VR102 VRLOL VR1O6
R | VR202 VR201 VR206
BIAS ADJUSTMENTS
Adjustment Locations
CH | BIAS ADJUSTMENTS | REC BIAS TRAP |
| HIGH BIAS NORMAL BIAS
~@ REVERSE FORWARD Be ~@ REVERSE FORWARD
[u VC1O3 ve1OL ve1o4 | vc102 | _t102 |
[R vC203 ve201 ve204__ | _vc202 | t2z02 |.
RECORD PERFORMANCE ADJUSTMENTS
cH REC LEVEL | Rec £Q | REC METER LEVEL
HIGH POSITION NORMAL POSITION _|
s@reverse | FORWARD D> | REVERSE | FORWARD
VR104 vrio3 | ----- VRLO8 L103 vR107
VR204 R203 — vr2os | 1203 vR207

PLAYBACK PERFORMANCE
PLAYBACK HEAD AZIMUTH ADJUSTMENT
Coarse Adjustment
PwNr
Connect a level meter to either OUTPUT jack.
Thread a TEAC test tape YTT-1003 on the unit.
Play the 15 kHz test tone in section 2 of the test tape.
Slowly rotate the azimuth screw until maximum indication is obtained
on the level meter. Repeat step 4, procedure for reverse head.
Fine Adjustment
8.
CAUTION
After coarse adjustment, do not make large corrections, turn
azimuth screw 1/4 turn or less.
It is absolutely essential to accomplish the coarse adjustment before
using this method to avoid phase errors larger than 45°
Connect the test equipment as shown in Fig. 7-8.
Play a 10 kHz signal and adjust the azimuth screw until the oscillo-
scope shows that the signals are less than 45° in phase. Repeat above
step for reverse head.
Secure the screw with a drop of LOCTITE.
HEIGHT
(Viewed from front of head)
AZIMUTH
(Viewed from front of head)
CORRECT ALIGNMENT
TANGENCY TILT
(Viewed from top of head) (Viewed from side of head)
zg
le,
ee
HEAD MIS-ALIGNMENT FOUR WAYS
e ALIGNMENT - The physical positioning of a tape head relative to the
tape itself. Alignment in all respects must conform to rigid re-
quirements in order for a unit to function properly.
e@ AZIMUTH - The angle of a tape heads pole-piece slot relative to the
direction
of
tape
travel.
Refer
to
Fig.
5-1
HEAD
ALIGNMENT.
NOTE
In order for a tape unit to work at its best, with its
own tapes as well as ones made on other units, its play
and record heads must be aligned in the four ways shown
above.

PLAY BACK HEAD
SS: oe
’ p (OUTPUT
“j
°
4
‘S2bj
Ss
.
ott
E
~454i
VRi02/202
NOTE
FORWARD
REVERSE
. Simplified diagram shown in the RIGHT
channel only.
+ @ Screwdriver adjustment.
« ££ on front panel.
CIT] on rear panel.
Fig. 7-2 Simplified Diagram -Playback-
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)
output
meter.
1.
Place
the
MONITOR
switch
in
TAPE
position.
2.
Turn
the
OUTPUT
controls
fully
clockwise.
3.
Apply
a
400
Hz
signal
at
operating
reference
level
(1%
of
the THD
level).
4.
Adjust
FORWARD
VR-101,
VR-201,
REVERSE
VR-102,
VR-202
to
obtaina
specified
output
level
of
-2
dB
at
OUTPUT
jacks.
5.
Retard
QUTPUT
controls
to
obtain
a
level
of
approximately
-8
dB
at
OUTPUT
jacks.
OUT
PUT
2-O'CLOCK POSITION
SPECIFIED LEVEL
IMPORTANT
This is the specified output level
set. Do not disturb this setting
until the remaining adjustments
have been completed.
M-or8i
PB METER LEVEL SET
1.
While
playing
the
400
Hz
tone
(1%
THD)
in
section
1
of
the
test
tape.
2.
With
MONITOR
switch
at
TAPE
position,
adjust
VR-106,
VR-206
for
a
reading
of
0
VU
on
the
VU
meter.