Teac A-4300SX User manual

MA3608X }
"4300SX
Stereo Tape Deck
TEAC
CORPORATION
51031780

1. GENERAL DESCRIPTION
The
TEAC
A-4300SX
is
an
excellent
home
entertainment
stereo
tape
deck
built
to
semi-profes-
sional
standards,
with
3
motors,
4
heads,
foil
sensing
auto-reverse
and
index-counter
repeat.
It
operates
at
3-3/4
ips
and
7-1/2
ips,
accepts
7”
reels,
and
features
switch-controlled
Bias
and
Equal-
ization;
dual
range
VU
meter;
two
line
input
jacks
per
channel;
remote
controlled
(optional)
oper-
ation;
and
other
convenient
features.
Although the A-4300 SX internally appears to be similar to A-4300, significant differences require
that
you
consult
this
manual
before
attempting
service.
The
A-4300SX
Service
Manual/Parts
Man-
ual
contains
adjustment
and
alignment
information,
schematic
diagram,
parts
replacement
refer-
ences, and other information for obtaining new parts.
TABLE OF CONTENTS
1. General Description .................04.0. 3
2. Specification and Service Data .............. 4
3. Tools for Testing and Maintenance............ 5
4. Partial Disassembly .................0--. 6
5. Tape Transport Parts Location .............. 8
6. Head Replacement and Alignment ............ 9
7. Measurement and Adjustment ............... 10
—MECHANICAL—
8. Measurement and Adjustment ............... 13
—ELECTRICAL—
9. Trouble-shooting ..............-2....00-- 20
10. Service and Maintenance ...............-.. 22
11. Simplified Schematic with level
INGICALIONS 33 hee Meals ete gaheds 2 ES ae Se 23

2. SPECIFICATIONS AND SERVICE DATA
2-1 SPECIFICATIONS
Track System 1/4 track 2 channel stereophonic
1/4 track 1 channel monophonic
Heads Four; Erase, Record and Playback x 2
Reel Size 7” maximum
Tape Speed 7-1/2 ips and 3-3/4 ips
Motors 1 Dual-Speed Hysteresis Synchronous Capstan motor
2 Eddy Current Induction Reel motors
Input MIC: Specified; -60 dB (0.774 mV)/10k ohms
(Level and Impedance) Minimum; —70 dB (0.244 mV)
LINE: Specified; —8 dB (308 mV)/50k ohms
Minimum; —18 dB (97 mV)
DIN: Minimum; —38 dB (9.75 mV)
Output LINE: Specified; —8 dB (308 mV)/10k ohms
(Level and Impedance) Maximum; —2 dB (615 mV)
DIN: Maximum; —2 dB (615 mV)
Playback Equalization 7-1/2 ips: NAB 3180 yp sec, 50 wu sec
3-3/4 ips: NAB 3180 p sec, 90 pu sec
Bias Frequency 100k Hz (+5k Hz, push-pull oscillator)
Power Requirement 100, 117, 220, 240 V AC 50/60 Hz (General Export model)
117 V AC 60 Hz (U.S.A. and Canada Model)
Weight 23 kg (51 Ibs) net
Power Consumption 90 W
Dimensions (WHD) 440 x 488 x 216 mm (17-5/16” x 19-1/4” x 8-1/2”)
2-2 SERVICE DATA —MECHANICAL—
Tape Speed Deviation and Drift 3,000 Hz +30 Hz, within 15 Hz
Wow and Flutter Playback: 0.18% (RMS) at 7-1/2 ips
0.20% (RMS) at 3-3/4 ips
Overall: 0.20% (RMS) at 7-1/2 ips
0.25% (RMS) at 3-3/4 ips
Pinch Roller Pressure 2.4 kg (5.3 lbs)
Reel Torque TAKE-UP:
FWD 370 to 410 g-cm (5.2 to 5.7 oz-inch)
REV 430 to 470 g-cm (6.0 to 6.6 oz-inch)
BACK TENSION:
FWD 170 to.210 g.cm (2.4 to 2.9 oz-inch)
REV 180 to 220 g-cm (2.5 to 3.1 oz-inch)
Brake Torque 800 to 1,200 g-cm (11 to 17 oz-inch)
F.F/REW Time 160 seconds for 1,800 foot tape
2-3. SERVICE DATA —ELECTRICAL—
Frequency Response Refer to Frequency Response Limits charts in this manual
Signal-To-Noise Ratio Overall: 48 dB at 7-1/2 ips
46 dB at 3-3/4 ips
Erase Efficiency 68 dB at 1k Hz signal
(Measurement with input 10 dB higher than the Specified Input level)
Cross
Talk
Rejection
40
dB
adjacent
track
at
125
Hz
Stereo
Channel
Separation
50
dB
Channel
to
Channel
at
1k
Hz
Total
Harmonic
Distortion
Overall:
1.5%
at
1k
Hz
signal
NOTE:
As
a
result
of
continuing
changes
and
improvements
during
the
production
run,
minor
differences
may
be
found
between
early
and
later
machines.
Value
of
“dB”
in
this
manual
refers
to
0
dB
=
0.775
V.

—
©@G@o geeoes
(410mm)
4 “
6% 84 -—"
17 5 (216 mm)
(440mm) 7-103
Fig. 2-1 Dimensions
3. TOOLS FOR TESTING AND MAINTENANCE
A minimuth of the following tools and test instruments are
required for measuring and adjusting to obtain optimum _ ee
performance.
Regular
maintenance
tools
will
be
adequate
ghee
URAC
LESE,YAPE
for those not listed here. If any test instrument listed here
is not available, a close equivalent can be used.
SPRING SCALE .........0.0-0. 0-4 kg (O— 8 Ibs)
0-300 g (0-10 oz)
FLUTTER METER ....... Meguro Denpa Sokki K.K..,
Model MK-668A Fig. 3-1 TEAC Test Tape
DIGITAL COUNTER ......... Range; 0 Hz—100 kHz
BANDPASS FILTER ...TEAC MODEL M-206A (1 kHz)
VTVM (AC) ...... ~. Hewlett-Packard Co., Model 400E
AF OSCILLATOR ........----05- 10 Hz—100 kHz
ATTENUATOR ........-..----55 General purpose
OSCILLOSCOPE .............--- General purpose
BLANK TAPE........ TEAC YTT-8023 and YTT-8003
TEAC TEST TAPE ... YTT-1003 (7-1/2 ips), YTT-1002
(3-3/4 ips) for Playback Alignment test
YTT-2003 (7-1/2 ips), YTT-2002 Fig. 3-2 Hex Head (Allen) wrench
(3-3/4 ips) for Tape Speed
and Wow Flutter test
TEAC EMPTY REEL.......... RE-702 (2.5” dia, hub)
RE-701 (4” dia, hub)
TOOK S 5 eee eo et i des SE ees General
2 mm nut driver
Hex Head Allen Wrench
Plastic alignment tool
Load resistor non inductive type 8 ohm / 1 W
DEMAGNETIZER .......... TEAC E-3 or equivalent
Fig. 3-3 Spring Scales

4, PARTIAL DIS- ASSEMBLY
4-1
REMOVING
WOODEN
SIDES
AND
REAR
PANEL
AND
BOTTOM
PANEL
See illustration for complete dis-assembly instructions.
Most amplifier checks and adjustments can be made from
the bottom with the (bottom) panel removed.
These adjustments should be performed by experienced
technicians, and then only when going through the com-
plete test and check procedures on the unit which is being
tested.
Head
Base Plate
Housing Base
Plate
Magli: e
Sues
ae
LUT
lee um lly Ih
Wyyytll
lin,
Fig. 4-2 Head Ass‘y Removal
4-3 REMOVAL OF CAPSTAN MOTOR
1. Remove the 3 screws holding the capstan motor plate.
2. Unsolder the 6 wires connecting the capstan motor.
3. Remove the 4 screws holding the capstan motor to the
motor plate. Watch for the Rupber Cushions (A).
4. Loosen the 2 set screws (hex head) in pulley and lift
off pulley (B). Loosen 2 set screws in fan and remove
fan.
SOOO
MMMM}
Fig.
4-1
Removing
Wooden
Sides
and
Rear
and
Bottom
panels
4-2 HEAD ASSEMBLY REMOVAL
1. Remove the 2 screws in the top of the head cover and
lift it off.
2. Remove 2 screws holding head Base plate (with Heads).
3. Remove 2 mounting nuts through access slot in head
i : [PPTL
Base plate and dis-connect head wires. See Fig. 6-2.
4. If necessary, remove Housing Base plate by 4 screws. oe
See Fig. 4-2. Fig. 4-3 Capstan Motor Removal

4-4 REMOVAL OF CAPSTAN ASSEMBLY
Dank WwW
. Unscrew dust cap(A) on front panel.
. Remove 2 screws from Thrust Angle (B). Allow bracket
to drop toward floor of case.
. Remove capstan belt (C).
. Loosen 2 screws in flywheel (D) Remove flywheel.
. Remove 3 screws in capstan ass’y (E).
. Gently move capstan ass’y up and down until it slides
out of panel.
NOTE: When replacing flywheel, position flywheel on
capstan ass’y shaft so that end of shaft protrudes
slightly
from
rear
of
flywheel.
A
clearance
of
ap-
prox. 0.01’’ must be maintained between the end
of the capstan shaft and the Thrust Angle.
Fig. 4-4 Capstan Ass‘y Removal
45 REMOVAL OF REEL MOTOR
1.
2.
Disconnect the 4 motor wires from terminals and
release wire harness straps.
Loosen 2 set screws (hex head) in Brake drum(A) and
2 in the Reel Turntable assembly(F). Lift off these
parts.
. Remove 4 screws securing the Brake Assembly(D) to
the motor. Carefully lift off the Brake Retainer(B).
Do not remove wires connected to the brake solenoid(C),
. Remove 4 screws securing Reel Motor(E) to chassis
through the front panel.
<> CHASSIS
FRONT PANEL
Fig. 4-5 Reel Motor Removal
4-6
REMOVAL
OF
TENSION
ARMS
LEFT
AND
RIGHT
See
illustration
for
complete
dis-assembly
instructions.
NOTE:
After
re-assembly
check
clearance
to
ascertain
that
arm
moves
freely
and
is not
binding.
Do
not
over-tighten
screws
holding
micro-switches.
Insulating
spacer
and
micro-switches
are
easily
broken
by
excess
pressure.
as panel
Fig. 4-6 Tension Arms Removal

5. TAPE TRANSPORT PARTS LOCATION
—REAR VIEW-—
Power
Brake Solenoid Transformer
c9 R11 RY R10
Rectifier PC Board
R12 : ( 1, : 2 ie £ = Brake Solenoid
Right Reel Motor Left Reel Motor
Cap. Motor
R19
Cap. Solenoid
Cap. Beit Freq. Adapt
PC Board (C7)
Sensing Ampl.
Cap. Flywheel
Control PC Board
Control SW Ass’y
Fuse Holder
NOTE: R9, R10 and R11 are adjustable resistors which are used to adjust take-up tor-
que and back tension. Refer to page 11 for the TORQUE MEASUREMENT
procedure.

6. HEAD REPLACEMENT AND ALIGNMENT
—MECHANICAL—
6-1 HEAD REPLACEMENT AND WIRING
To replace a single head a special 2 mm nut driver is re-
quired. Remove the 2 nuts (A) on the defective head
through the access hole provided. This releases the head
from the mounting plate. Note the position of the wires on
the circuit board. Connect the new head in the same man-
er. Replace the nuts securing the new head to the plate.
Perform head alignment before operation.
r
aN NUTS (A)
{
ee PLAYBACK x
RECORD REVERSE — i FORWARD
Fig. 6-2 Head Wiring —.Rear View —
6-2 HEAD ADJ. SCREWS AND ALIGNMENT
8 9
i)
@ oe
© © @ dg 652°2
e © @
Tape
Lifters
t
Tape
Guides
va
—
—
—
—
eo
ose
eeepc
REVERSE
FORWARD
Toe
—~——
ERASE
RECORD
<T)
Playsack
[=>
——
@ Azimuth adj. screws
© Height and Tilt adj. screws
© Tangency adj. Nuts
Fig. 6-3 Head Adjustment Screws and Alignment
6-3 VISUAL HEAD ALIGNMENT
Since
the
propriety
of
head
alignment
affects
the
frequency
response
on
both
playback
and
recording,
the
head
align-
ment
should
be
done
carefully.
The
head
can
be
adjusted
in
TILT,
TANGENCY,
HEIGHT
and
AZIMUTH.
For
head
alignment,
perform
the
following
coarse
adjust-
ments
first.
Then
fine
alignment
should
be
accomplished
electrically
while
playing
back
the
Test
Tape.
Coarse Adjustment:
Without Tape
BIE otic 3 eras By Height and tilt screws
This
alignment
is
performed
by
viewing
from
the side without tape threaded.
Check
that
the
head
surface
is
parallel
to
the
tape guide surface.
With Tape
TANGENCY .... By Head mounting Nuts
Loosen
the
head
mounting
nuts.
Adjust
the
head so that the vertical alignment of the head
gap
is
perpendicular
to
the
surface
of
the
tape,
then tighten the head mounting Nuts.
HEIGHT ....... By Height and Tilt screws
This
alignment
is
checked
visually
by
looking
at the position of the head.
The
head
core
for
track-]
(inner
core)
should
be even with the inner edge of the tape.
AZIMUTH ...... By Azimuth adj. Screw
Adjust
the
azimuth
adj.
screw
so
that
the
gap
of
the
head
is
perpendicular
to
the
tape
travel.
NOTE:
After
this
coarse
adjustment
is
made,
the
adj.
screws
and
the
Head
mounting
nuts
should
be
realigned
according
to
electrical
head
alignment
paragraph
which
follows
in
this
Service
Manual.
6-4 MIS-ALIGNMENT OF THE HEADS
i TILT [3] HEIGHT
iview from side of head)
(view from front of head)
crews | Adjust by @ Screws
TANGENCY
view from top of head)
i_()
AZIMUTH
(view from front of head)
crews
T-615
Fig. 7-3. Head Mis-Alignment —Examples—

7. MEASUREMENT AND ADJUSTMENT
—MECHANICAL—
7-1 PINCH ROLLER PRESSURE
NOTE: Pinch roller pressure is supplied by the pinch roller
spring arm and it is most important that the sole-
noid plunger be fully bottomed before taking
pressure measurement.
. Load tape or block the shut-off arm in the ON position.
2. Attach a suitable spring scale to the pinch roller shaft.
3. Place the deck 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 to 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 2.3 to 2.5 kg (5.0 to 5.5 lbs).
Optimum value is 2.4 kg (5.3 Ibs).
7. If adjustment is necessary, loosen the 3 screws on the
capstan solenoid and position the solenoid for optimum
pressure.
8. Adjust solenoid-limit position so that the gap between
capstan shaft and pinch roller is approx. 7 mm when
solenoid is not actuated. Also make sure pinch roller
shaft does not contact edit arm B. Limit is adjusted by
loosening the mounting screw (A), then sliding limit
until proper position is obtained.
—
CAPSTAN SOLENOID LIMIT
Fig. 7-1 Pressure Measurement and Adj. Locations
10
7-2. BRAKE TORQUE
The brake torque is actuated mechanically. Pressure is set
by the leaf spring force. While making these measurements
and adustments, 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 neces-
sary. If cleaning is required, use TEAC cleaner TZ-261B.
After cleaning, operate the brakes by depressing the play
and STOP buttons several times to completely dry out the
brakes before performing the following procedure.
NOTE: Brake adjustments are made with NO power con-
nected to the equipment.
1. Place an empty large hub reel on the left reel table, and
fasten one end of a 30” length of string to the reel
anchor.
2. Wind several truns of string counter clockwise around
the hub and attach a suitable spring scale to the free end
of the string.
3. 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.
4. The Calculated value should be 800 to 1200 g-cm (11
to 17 oz-in).
5. If adjustment is required, loosen the 2 screws shown and
position the brake for optimum torque.
6. The adjustment of the right brake is the same, with the
exception that rotation is clockwise.
(wind string CLOCKWISE around ree! hub)
7. See note at the top of page 11 for explanation of torque
measurements.
Solenoid
Brake Drum
ADJUSTMENT SCREWS
T
H
Fig. 7-2 Torque Measurement and Adjustment Location

TORQUE MEASUREMENT PROCEDURE
OTE: The following torque measurements should be
made with a spring scale that is calibrated to read
Torque in gram-cm, for a 7” reel with a small reel
hub. If the spring scale you are using is calibrated
to read Force or Weight in grams the Torque must
be calculated using the Formula:
Torque (in g-cm or 0z*in) =
Weight or Force (in gm. or 02.) x
radius of hub (in cm or inches)
If you are using a reel with other than the standard 2.5” or
6.0 cm (approx.) diameter hub, the Torque must be cal-
culated using the same formula and substituting the actual
radius and Weight or Force reading.
All Torque and Tension measurements must be made with
the automatic shut-off switch (right tension arm) held in
the ON position.
Brake Torque Measurement should be made using large hub |
reel with a hub diameter of 4” or 10.2 cm.
1-626
Fig. 7-3 Torque Measurement
7-3. TAKE-UP TORQUE
1. Place the empty reel and attached spring scale on the
right reel table:
2. Place the deck in the Forward Play mode.
3. Allow the rotation of the reel to slowly draw the scale
toward the hub.
4. Hold the spring scale with enough force to allow a
steady reading.
5. The torque calculated valve should be approx:
370 to 410 g-cm (5.2 to 5.7 oz-inch)
6. Repeat the procedure for the Reverse play.
430 to 470 g-cm (6.0 to 6.6 oz-inch)
RRR RSE NRE PD Re pea
ee
EE EN PEN ee ters
Aol _Tavengyen cea me coaae cae oan arrestee ener canerscemiormere i
7-4 BACK TENSION
1. Place an empty 7” reel with small hub on the left reel
table, and fasten one end of a 30” length of string to the
reel anchor.
2. Wind several turns of string counter-clockwise around
the hub. Attach spring scale to string.
3. Place the deck in the Forward Play mode.
4. Pull the scale away from the reel against the motor torque
with a steady, smooth motion.
5. Note the scale reading while it is in steady motion.
(The string must not rub-the reel flanges)
6. The calculated value should be approx.:
170 to 210 g*cm (2.4 to 2.9 oz-inch)
7. Repeat the procedure for the Reverse Play.
Using the right reel table. 180 to 220 g+cm (2.5 to 3.1
oz-inch)
Adjustment Location
If necessary, adjust slider of the resistors until you have the
correct scale reading for optimum torque. Refer to adj. lo-
cation below.
REVERSE FORWARD
TAKE-UP TORQUE |
| TAKE-UP TORQUE
t =
REVERSE uit c
=
BACK TENSION
FORWARD | ®
7-5 REEL HEIGHT ADJUSTMENT
Reel height adjustment is required only if a motor has been
replaced or if tape rubs excessively against the reel. Adjust-
ment is accomplished by FINE ADJ. screw in the reel turn-
table. Reel turntable height should be checked using stan-
dard 7” reels. With a tape threaded on the machine, position
the reel height for smooth tape travel. If adjustment is
necessary, remove the reel and adjust the screw. Then
replace the reel and re-check the adjustment.
1

7-6 TAPE SPEED
The tape speed should be measured using TEAC flutter free
tape, Model YTT-2003 (7-1/2 ips), YTT-2002 (3-3/4 ips).
These tapes contain a highly accurate 3,000 Hz tone. Con-
nect a digital frequency counter to either line OUTPUT
jack. The indicated frequency should be 3,000 Hz £30 Hz
for both speeds and both directions.
7-7 WOW AND FLUTTER CHECK
NOTE: Before performing this measurement, clean the
head and Tape run guides, also check pinch roller
pressure, etc.
Use new Test Tape if possible for following adjust-
ments.
Values obtained with different standards of equip-
ment cannot be compared.
PLAYBACK
1. Connect Test equipment to the unit as shown in Fig. 7-5.
(Except oscillator).
2. Load TEAC YTT-2003 (for HIGH, 7-1/2 ips) or YTT-
2002 (for LOW, 3-3/4 ips) and playback tape.
. Read the indication on the Wow and Flutter meter.
4. The Wow and Flutter should be
0.18% (RMS) for 7-1/2 ips
0.20% (RMS) for 3-3/4 ips
WwW
OVERALL
1. Connect Test equipment to the unit as shown in Fig. 7-5.
2. Load TEAC YTT-8003 (blank tape) Test Tape on the
unit and Record a 3,000 Hz input signal.
. Rewind and playback the recorded signal.
4. The reading on the Meter should be
0.20% (RMS) for 7-1/2 ips
0.25% (RMS) for 3-3/4 ips
WwW
NOTE: These figures apply to any tape position (such as
full take-up reel, full supply reel or about mid-
point). Also examine the tape counter ass’y for
evenness of operation.
FREQUENCY COUNTER
DECK WOW & FLUTTER METER
under TEST
Fig. 7-5 Test Connections for Wow/Flutter and
Tape Speed Test
12
7-8 VOLTAGE AND FREQUENCY
CONVERSION
This deck is adjusted to operate on an electric power source
of the voltage and frequency specified on the reel tag and
packing carton. If it is necessary to change the frequency or
voltage requirements of this deck to match your area, use
the following procedures.
Always Disconnect Power Line Cord before making these
changes.
Frequency Conversion: (only Export model)
1. Remove the right side wood panel (4 screws), then the
rear/top metal panel (6 screws).
2. Set the power frequency selector slide switch (located
next to the capstan motor) to the 50 or 60 position to
match the power line frequency in your area.
3. Rotate the center (capstan) motor clockwise with your
hand and re-position the belt onto the correct pulley as
shown in the Motor Pulley Illustration below.
The pulley can be seen by looking through the opening
in the side panel. Continue to rotate the motor by hand
approximately 10 revolutions to verify belt placement
before replacing the side and rear covers.
Capstan
C3 Flywheel
Rotate motor clockwise E | (|
while changing belt | 50_Hz 60
position.
©
a]
@
Selector Slide Switch
Fig. 7-6 Frequency Conversion
Voltage Conversion: (only Export model)
The deck may be set for 100, 117, 220 or 240 volts. To
change the voltage unscrew the fuse in the center of the
voltage selector plug. Pull out the plug and reinsert it so the
desired voltage shows in the cutout. Reinstall the fuse speci-
fied on the label on the rear of the deck.
Fig. 7-7 Voitage Conversion

8. MEASUREMENT AND ADJUSTMENT
—ELECTRICAL—
NOTE:
Before
performing
maintenance
on
this
deck,
throughly
clean
and
demagnetize
the entire Tape path, TEAC maintenance equipment to be used:
TEAC TZ-261 A/B for cleaning
TEAC E-3 for demagnetizing or equivalents
Service Data were determined using TEAC YTT Series Test Tape.
Procedure for checks and adjustments, unless otherwise indicated, are for the
left channel at a tape speed of 3-3/4 ips (9.5 cm). The same procedures are to be
applied to the right channel and again for both channels at 7-1/2 ips (19 cm)
speed.
The deck must be matched to the voltage and frequency of your locality.
Most amplifier checks and adjustments can be made from the bottom with the
(bottom) metal panel removed.
8-1 ADJUSTMENT LOCATIONS AND ADJUSTMENT POINTS
ADJUSTMENT |
ee aa fe Ref. Nos 68 SOUS TVENT
P.B.EQ (HIGH) VR101/103 RECORD LEVEL VR303/306
P.B.EQ (LOW) VR102/104 REC EQ L301/303
BIAS TRAP (For OUTPUT)| —__L201/202 BIAS TRAP L302/304
P.B. LEVEL VR201/203 DUMMY COIL L401
P.B.METER CAL. VR202/204 BIAS ADJ. (SW-1) vc401/402
RECORD METERCAL. | VR302/305 BIAS ADJ. (SW-2) vRa01
MONITOR LEVEL [_.vR301/304 ja stbos chan.) _|
Ampl PC Board Location and Adjustments Points

8-2 ADJUSTMENT SEQUENCE CHART
POWER SUPPLY PLAYBACK HEAD OUTPUT VU METER FREQUENCY SIGNAL-TO-NOISE
CHECK AND ADJ. [“"} AZIMUTH ADJ. LEVEL SET LEVEL SET RESPONSE —PLAYBACK~ RATIO —PLAYBACK—
* MIC INPUT VU METER SPECIFIED LINE < MONITOR HEADPHONE
| LEVEL CHECK LEVEL SET CONTROL SETTING LEVEL SETTING OUTPUT CHECK
BIAS TRAP BIAS RECORD HEAD
ADJUSTMENT LEAKAGE CHECK AZIMUTH ADJ.
BIAS
RECORD
PRSEnGE
ADJUSTMENT
|
a
|
~
OVERALL
~
|
CROSS TALK
REJECTION
TRACK TO TRACK
DISTORTION
CHECK
CHANNEL OPTIMUM ERASURE SIGNAL-TO-NOISE
SEPARATION MEASUREMENT RATIO —- OVERALL —
Fig. 8-1 Adjustment Sequence Chart
PLAYBACK PERFORMANCE
8-3 POWER SUPPLY CHECK AND ADJ.
1. Remove metal panel on Rear side of the deck for access
to the electrical adjustments.
2. Depress power SW to ON.
3. Connect a VITVM between the Control P.C.B. Test Point
No. 3 and ground. See Fig. 8-2 below.
4. Adjust VR-1 for +23 V DC.
VRI
Fig. 8-2 +23 V DC Test Point
8-4 PLAYBACK HEAD AZIMUTH ADJ.
NOTE: Befoite proceeding with the following head align-
ments be sure that heads have been properly
mounted as to HEIGHT, TILT and TANGENCY.
See page 9.
— Fine Adjustment —
TAPE SPEED SW . . . 3-3/4 ips (9.5 cm)
OUTPUT SW .............. TAPE
METERSW............ NORMAL
14
1. Connect a VTVM to OUTPUT jacks.
2. Remove the head housing by removing 2 screws.
3. Thread the TEAC YTT-1002 Test Tape on the deck.
4. Play the 16 kHz/—10 dB Test tone in section 2 of the
Test Tape.
. Slowly rotate the azimuth Screw until maximum indica-
tion is achieved on VTVM.
. Connect an oscilloscope to the OUTPUT jacks.
. Adjust the azimuth screw (If necessary) until the oscillo-
scope shows that the signals are less than 45° out of
phase at 10 kHz signal.
. Secure this screw with a drop of locking paint.
.
Depress
the
«@
button
and
turn
agimuth
adjustment
screw
Fig.
6-3
of
the
reverse
playback
head
for
maxi-
mum
indication
on
the
VTVM
or
scope.
nm
a On
eo 90
OSCILLOSCOPE
AMPL SPKR
DECK
under TEST
T- 309-2
Fig. 8-3 Head Alignment Fine Adjustment Set-up and
Test Connections (PLAYBACK)

8-5 OUTPUT LEVEL SETTING
—
MAXIMUM
OUTPUT
LEVEL
CHECK
—
10.
Play
the
400
Hz/O
dB
tone
in
section
1
of
the
Test
Tape.
11.
Turn
the
OUTPUT
controls
fully
clockwise.
12.
Adjust
VR-201/203
for
—2
dB
(615
mV)
at
OUTPUT
jacks.
— SPECIFIED OUTPUT LEVEL SETTING —
13.
Reduce
both
OUTPUT
controls
together
until
the
lower
reading
channel
reads
—8
dB.
(approx.
2
o’clock
position).
14.
If
there
is
a
difference
in
level
between
L-ch
and
R-ch,
again
adjust
VR-201/203
(whichever
is
higher)
for
—8
dB
(308
mV).
NOTE: This is the Specified Output level setting. Do not
disturb
this
setting
until
the
remaining
adjustments
have been completed.
15. Adjust VR-202/VR-204 for 0 VU (at NORMAL scale)
reading on VU Meters, Set METER SW to HIGH. 0 VU
should be read on HIGH scale.
8-7 FREQUENCY RESPONSE —PLAYBACK—
16. Thread TEAC YTT-1002 on the deck.
17. Play Tape and compare reading on VTVM with the re-
sponse limits given in Fig. 8-5.
18. If adjustment is required, adjust VR-101/VR-103 for
3-3/4 ips (9.5 cm) speed.
19. Change Tape SPEED SW to 7-1/2 ips (19 cm) position.
20. Thread TEAC YTT-1003 on the deck.
21. Repeat Step 17.
22. If adjustment is required, adjust VR-102/VR-104 for
7-1/2 ips 19 cm) speed.
NOTE: If the frequency response does not meet specified
response limits, especially at the high-end of the
spectrum, head should be checked for accumu-
lated dirt or oxides. If clean, head azimuth must
be readjusted.
RESPONSE IN dB.
t
a‘
RESPONSE IN dB
mo
N
ES
1K
FREQUENCY IN Hr
Fig. 8-5 Frequency Response — PLAYBACK —
—
REVERSE
PLAYBACK
HEAD
CHECK
—
Depress ~@ (Reverse Play) button and check for suitable
output from both channels. If necessary adjust Height
and azimuth adj screws (See Fig. 6-3) of Reverse Play-
back Head for best output.
8-8 SIGNAL-TO-NOISE RATIO —PLAYBACK—
1. OUTPUT controls should be at the Specified Output
level settings.
2. Thread a YTT-1003 on the unit leaving the tape outside
the capstan and pinch roller.
3. Hold the play supply reel stationary and depress the play
(> ) button.
4. The VITVM connected to the OUTPUT jacks should indi-
cate readings listed below.
HIGH (7-1/2 ips) ........... 50 dB
LOW (3-3/4ips) ........... 48 dB
8-9 HEADPHONE OUTPUT CHECK
1. Connect an 8 ohm non-inductive resistor across the
headphone (PHONE) jack.
2. Connect VTVM across the resistor. VITVM should indi-
cate —24 dB +2 dB (61 mV ~ 39 mV).
15

MONITOR PERFORMANCE
8-10 MONITOR LEVEL SETTING
OUTPUT SW SOURCE
1. Turn LINE controls fully clockwise.
2. Apply a 400 Hz —18 dB (97 mV) signal from AF oscil-
lator to LINE IN jacks.
3. Adjust VR-301/VR-304 for —8 dB (308 mV) at the
OUTPUT jacks.
OSCILLOSCOPE
DECK
under TEST
1-390-1
Fig, 8-7 Test Connections for Monitor Check
8-11 SPECIFIED LINE CONTROLS SETTING
4
. Apply a 400 Hz —8 dB (308 mV) signal from AF oscil-
lator to LINE IN jacks.
5. Adjust LINE controls for —8 dB (308 mV) at OUTPUT
jacks.
NOTE: At this point both the line controls and OUTPUT
controls are at the “Specified setting”. Do not
move these controls unless instructed in this proce-
dure to do so.
The accuracy of many of the following adjust-
ments and readings depends on these controls
being at the “Specified setting”’.
8-12 VU METER LEVEL SET
6
7
. Check VU Meters for 0 VU indication.
. Adjust VR-302/VR-305 for 0 VU, if necessary.
8
-13. MIC INPUT LEVEL CHECK
This is check only. No adjustment is to be made.
i,
2.
3.
7
Decrease
LINE
controls
to
minimum
position.
Set
MIC
controls
fully
clockwise.
Apply
a
400
Hz
signal
at
—70
dB
(0.244
mV)
to
the
MIC
input jacks.
. Check for —8 dB (308 mV) level at OUTPUT jacks.
. With —8 dB (308 mV) at OUTPUT jacks, MIC input
level should be —70 dB +2 dB (0.194 mV ~ 0.308 mV).
.
Return
MIC
controls
fully
counter
clockwise
to
prevent
noise insertion during following steps.
. Reset the LINE controls, to the “Specified setting”.

RECORD PERFORMANCE
8-14 BIAS TRAP ADJUSTMENT
OUTPUTSW ...........- TAPE
RECORD MODE (L, R) SW .... ON
BIAS and EQSW .......----- 1
Select REC PAUSE mode
1. Remove all input signals.
2.
Connect
a
VTVM
or
oscilloscope
from
ground
to
the
junction
of
L-302
and
C-314
(L-ch)
and
from
ground
to
the
junction
of
L-304
and
C-329
(R-ch).
See
Fig.
8-8.
3.
Adjust
L-302
(L-ch)
and
L-304
(R-ch)
for
minimum
reading
on
scope
or
VTVM.
Use Plastic alignment tool.
Test Point
T-719
Fig. 8-8 Bias Trap Test Point
8-15 BIAS LEAKAGE CHECK
4. With Output control and Line controls at any positions
Bias Leakage should be following value at OUTPUT
jacks,
Spec. —40 dB (7.75 mV).
Check both the SOURCE and the TAPE position.
8-16 RECORD HEAD AZIMUTH ADJ.
Tape SPEEDSW...... 3-3/4 ips (9.5 cm)
NOTE: The effect of turning the azimuth screw will reg-
ister on the VTVM. A slight delay will be noticed.
Therefore, the screw must be rotated slightly with
a pause to see the effect.
~Fine Adjustment—
5. Connect a VTVM to the OUTPUT jack and an AF oscil-
lator to the LINE IN jack.
Set the oscillator to 10 kHz at —18 dB (97 mV).
6. Begin recording (Depress REC and PLAY buttons).
7. While recording, adjust the azimuth screw for maximum
reading on the VTVM.
NOTE: It is absolutely essential to accomplish the above
adjustment before performing the following adj. to
avoid phase errors greater than 45°.
8.
Sweep
the
oscillator
frequency
from
50
Hz
to
10
kHz
(for
7-1/2
ips),
50
Hz
to
7.5
kHz
(for
3-3/4
ips)
and
check
that
phase
difference
between
channel
is
45°
or
less.
9. Secure the screw with insulating locking paint.
OSCILLOSCOPE
OSCILLATOR
Ee AMPL sP
LINE INL? (L)OUTPUT
DECK
Lins] under TEST im
Fig. 8-9 Test Connection for Recording Check
8-17 BIAS ADJUSTMENT
Be
sure
the
Bias
Trap
has
been
adjusted
per
section
8-14
before
proceeding.
10.
Apply
7
kHz
signal
at
—18
dB
(97
mV)
to
the
LINE
IN
jacks.
11.
While
recording
on
the
YTT-8003
Test
Tape,
adjust
capacitor
VC-401/VC-402
for
peak
reading
on
the
VTVM,
then
turn
the
capacitor
clockwise
until
a
de-
crease
of
2.5
dB
“over-bias”
from
the
peak
is
obtained.
BIAS and EQSW .............. 2
12.
Apply
400
Hz
signal
at
—18
dB
(97
mV)
to
the
LINE
IN
jacks.
13.
While
recording
on
the
YTT-8023
Test
Tape,
adjust
VR-
401
(both
chan.)
for
an
Over-Bias
of
0.5
dB
from
the
peak.
—> OUT
— => BIAS
T- 712
Bias Limits Chart
17

8-18 RECORD LEVEL SET
14. Apply 400 Hz signal at ~8 dB (308 mV) to the LINE IN
jacks.
Be sure the Line and Output controls are still at their
BIAS and EQ SW
23:
24.
Apply signals swept from 40 Hz to 14 kHz to the unit
while recording on a blank TEAC YTT-8023 Test Tape.
Repeat the above procedure for HIGH, using a signal
20.
21.
. Apply signal swept from 40 Hz to 24 kHz, —28 dB (30.8
previously set positions.
15. Begin recording.
16.
PUT jacks.
8-19 FREQUENCY RESPONSE —OVERALL—
NOTE: To avoid saturation of the tape these checks should
be made at least 20 dB below the specified input
level.
Any Bias signal feeding into the test equipment
should be filtered out by adjusting the external
Bias Trap.
BIAS and EQSW .... 2... ee ee ee 1
Tape SPEEDSW...... 3-3/4 ips (9.5 cm)
. Apply signal swept from 40 Hz to 16 kHz, —28 dB
(30.8 mV) to the LINE IN jacks and record on a blank
TEAC YTT-8003 Test Tape.
During recording, monitor the Tape signal and adjust
equalization L-301/L-303 for readings within the Re-
sponse Limits charts. See Fig. 8-10 below.
Change the Tape SPEED SW to HIGH position.
mV) and while monitoring the off-the-Tape signal check
for readings within the Response Limits charts. See Fig.
8-10 below.
| Hil
fs fof tt tf +—
3-3/4 ips
mooes titi it
| +5
+4
+3
gra-——- + ‘ae 3
z
40 4 es
z au
8-2
#
“a = |
++ tt ttt
4 ‘wo 125 400 500 mK 5K OK 14K 16K 50K
FREQUENCY IN Hz
RESPONSE IN df
Fig. 8-10 Frequency Response — OVERALL — 1
Adjust VR-303/VR-306 for —8 dB (308 mV) at OUT-
swept from 40 Hz to 22 kHz. Refer to Response Limits
in Fig. 8-11 below.
NOTE: If the response is not uniform, the head should be
cleaned of accumulated oxide and dirt. Then repeat
the Bias adjustment procedure by VR-401 (both
channel).
THT
3-3/4 ips
* 2
+ n
No
RESPONSE IN dB
RESPONSE IN dB.
1
Ey
FREQUENCY IN Ha
Fig. 8-11 Frequency Response —- OVERALL — 2
8-20 SIGNAL-TO-NOISE RATIO —OVERALL—
1. Output and Line controls should be at the specified
positions.
2. Remove the AF oscillator from the LINE IN jacks.
3. Place the deck in the Record mode with “‘no signal”
applied. Note the point on the index counter where
recording begins.
4. Rewind the tape (YTT-8003) to the beginning pointand
play it back.
5. The noise level as indicated on the VITVM should be
readings listed below.
HIGH (7-1/2 ips) .......... —56 dB
LOW (3-3/4ips) .........-. —54 dB
6. This -56 dB/—54 dB corresponds to the Signal-To-Noise
Ratio
of
48
dB/46
dB
(minimum):
the
difference
between
residual
noise
of
—56
dB/—54
dB
and
the
specified
p
ut-
put
level
-8
dB.
—8
dB
reference
level
is
also
appliable
following
measurements.

8-21 OPTIMUM ERASURE MEASUREMENT
Tape SPEEDSW....... 7-1/2 ips (19 cm)
1.
Thread
the
TEAC
YTT-8003
Test
Tape
on
the
unit.
2.
Apply
a
1
kHz
signal
at
10
dB
above
the
operating
level
of
—8
dB
(975
mV)
to
the
LINE
IN
jack.
3.
Make
a
30
seconds
recording
of
the
above
signal
while
reading
and
noting
the
level
of
output,
then
rewind
to
beginning
of
this
recording.
4.
Disconnect
the
1
kHz
signal
source
(AF
oscillator)
from
the
LINE
IN
jack.
5. Connect a VIVM to the OUTPUT jack, through a 1 kHz
Narrow Band Pass Filter.
6.
Put
deck
in
the
Record
mode
and
“‘record”
(erase)
over
this
previous
recording,
then
rewind
to
beginning
again.
7. Put deck in Play mode and monitor the output on the
VTVM.
8.
Difference
in
output
level,
between
the
1
kHz
signal
and
the
‘‘no
signal”
section
level
should
be
more
than
68
dB.
NOTE: Filter loss should be considered.
OSCILLOSCOPE
OSCILLATOR
es DECK
under TEST F
Fig.
8-12
Test
Connections
for
Erase
measurement
8-22 CHANNEL SEPARATION
1. Be sure tape is completely bulk erased prior to doing
these checks.
2. Apply a 1 kHz signal at —8 dB (308 mV) to L chan.
3. Place deck in Record mode.
4. While recording measure the OUTPUT on Rchan. VTVM
connected through a 1 kHz Band Pass Filter.
Spec. should be 50 dB.
OSCILLOSCOPE
DECK
under TEST
ATTENUTOR
JouTPUT ikHz FILTER
° °
Fig. 8-13 Test Connections for Channel separation check
8-23 CROSS TALK REJECTION
(TRACK TO TRACK)
Following
is
the
measurement
procedure
at
7-1/2
ips
using
the TEAC standard tape, Type YTT-8023:
1.
Thread
a
blank
tape
or
the
YTT-8023
tape
on
the
unit.
2.
Apply
a
125
Hz
signal
at
—8
dB
(308
mV)
to
the
right
and left channel LINE IN jack.
3. Make a 30 second recording of the 125 Hz signal.
4.
Interchange
the
left
and
right
reels
and
rethread
tape
on
the
unit.
.
Connect
a
VTVM
to
the
right
channel
OUTPUT
jack.
6.
Playback
the
recorded
signal
portion
of
tape
and
moni-
tor
the
level
on
the
VTVM.
. The reading should be 4 8 dB.
8. Spec. should be 40 dB.
nn
—
8-25 DISTORTION CHECK
Tape SPEEDSW..... 7-1/2 ips (19 cm)
BIAS and EQSW ...........--- 1
9. Thread the TEAC YTT-8003 Test Tape on the unit.
10. Apply a 1 kHz signal to LINE IN jacks.
11. Place the deck in the record mode for about 10 seconds.
Rewind and play this recorded section of the tape.
12. Read the indicated value on the distortion analyzer.
13. The distortion factor should be 1.5 %.
OSCILLOSCOPE
AMPL. SPKR
DISTORTION ANALYZER
OSCILLATOR
DECK
under TEST
ATTENUATOR wey
Toes!
Fig.
8-14
Test
Connections
for
Distortion
check

20
MECHANICAL
9. TROUBLE-SHOOTING-1
NOTE: The following guide lists specific difficulties that could occur in the A4300SX.
Possible causes are listed for each malfunction.
Visually inspect the unit for any damage such as broken or burned components
or wiring, loose connections, etc.
MALFUNCTION
POSSIBLE
SOURCE
OF
TROUBLE
|
Fuse burns out (blows) when power applied ————+» Faulty C6, D3 or D4
Capstan motor fails to rotate
when Tension Arm is ssi aca Rt SW2 or motor defective
Drive belt off or slipping
Transport inoperative in Forward
Playback
or
Fast
Forward
|
EEE
Ss
Remote
Control
dummy
plug
missing
or
loose
Faulty
K4
or
associated
parts
Either reel motor inoperative in playback but
OK in Fast Forward Defective tap on wirewound Resistor
Shorted motor capacitor or wiring
Associated circuit parts
Both reel motors operate with high torque
in Fast Forward mode ——__—————--_ Defective CR16, CR17
Excessive pene OO ae eee Head alignment improper
Faulty K8 or associated parts
Counter Repeat operation faulty 1» Defective Counter SW-10 ro SW-11, K3, K7
Auto Reverse sensing inoperative-———________» Faulty K6, QS, Q6 or associated parts
Reverse mode inoperative ————__-————_——__» Faulty K3, K5 or associated parts
Wow-Flutter excessive
(irregular tape movement) Improper pinch roller pressure
os Oily or defective belt
Back tension too high
Pinch Roller fails to engage ick Ca Faulty solenoid
Defective Q3, Q4, K8 or associated parts

9. TROUBLE-SHOOTING-2
NOTE:
Reference
numbers
given
for
the
Amplifier
section
are
Left
channel
designations.
Refer
to
the
schematic
diagrams
Right,
for
channel
reference
numbers.
Prefix letters indicate:
C: Capacitor D: Diode
Q: Transistor CR: Spark Killer (Cap.)
K: Relay SW: Switch
ELECTRICAL
a
MALFUNCTION
POSSIBLE
SOURCE
OF
TROUBLE
|
@ Amplifier inoperative — we Defective Q]1, Q2 or associated parts
@ Playback audio intermittent or absent
a) If SOURCE Monitor function
ROU ee Play head plug loose or disconnected
Q101, Q102, Q103 or associated parts
b) If SOURCE Monitor function
inoperative
Grounding
strap
loose
or
disconnected
from
the
power
amplifier PC
Board
Faulty
Q201, Q202
or the
associated
parts
VU
Meter
inoperative
in TAPE MONITOR mode
(OUTPUT
Switch
at
SOURCE)»
Defective
monitor
switch
Q203
or
associated
parts
VU Meter inoperative
in SOURCE monitor mode
(OUTPUT
Switch
at
TAPE)
>
Defective
monitor
switch
Q309
or
associated
parts
VU Meter inoperative in both modes ————_—___—» Faulty meter or wiring
Will not record and
RECORD Indicator lamp illuminates
a) No erase action ————_______—————» Faulty Q401, Q401, Q402 or associated parts
b) VU Meter SOURCE monitor function
a NL Dirty Record head
Defective Q301 or associated parts
Will not record and RECORD Indicator lamp
does not Ty ee RS RECORD-MODE switch
Faulty K401
— = | Lmause] (RecoRD
te: 0.1nF/ 4004 |
123456789011
RC-140 REMOTE CONTROL SCHEMATIC
21