Teac A-300 User manual

Stereo
Cassette
Deck
with
Dolby
System
NOTE
If
any
of
the
adjustments
or
repairs
seem
too
compli-
cated
or
are
difficult
to
accomplish,
please
contact
the
nearest
TEAC
Factory
Service
Department
or
write
directly
to
a
TEAC
office,
the
addresses
of
which
are
printed
on
the
back
cover
of
this
manual.
When
ordering
replacement
parts,
please
refer
to
the
PARTS
LIST
which
is
printed
separately
from
this
manual
and
included
as
an
insert.
TEAC
CORPORATION
51032580

TABLE OF CONTENTS
1. Test Equipment Required ............. 2 5, Mechanical Checks and Adjustments ...... 9
5-1. Take-up & Supply Torque ...........-. 9
2. Specifications & Service Data ........... 3 5-2. Fast Forward & Rewind Torque ......... 9
5-3. Pinch Roller Pressure... 2... 2. ee eee 9
TEAC Test Tape... 0... eee ee 3 5-4, Tape Speed/Wow and Flutter ........... 10
3. Parts Location .......... 0002-00000. 5 6. Electrical Chekcs and Adjustments........ 11
6-1. Playback Performance .............04. 11
4, Itlustrated disassembly procedures ........ 6 6-2. Monitor Performance .............-5- 13
4.1, External Parts 2.2.0... .0...0c..0.00000- 6 6-3. Recording Performance .............-. 14
4.2. Cassette Damper (Damper Cord Stringing)... 6 6-4, Adjustment Location ..............0- 20
4.3, Cassette Holder Ass’y .............0.. 6
4.4, Heads and pinch rollers ............... 7 7. Block Diagram ...... in deft ae at aes Ste tagey on 21
4.5, Reel Tablesi a cescc.e onc oa tho ee aeceeacre 7
4-6. Brake Plate Ass’y ............200000. 7 8. Eevel Diagram 2.440 eck os ee obese Oakes 21
4-7. MOtobs ax 42d tiled ge 884 see Fons 8
4-8, Capstan Drive Assy .............000. 8 9. Voltage and Frequency Setting .......... 23
4-9, Lubrication vc ..cg shee eiaiee sy oP RSS 8
4-10, Ilder/Tension Pulley Ass’y ............. 8
* Noise reduction circuit made under license from Dolby
Laboratories Inc. The word “Dolby” and the Double-D
symbol are trademarks of Dolby Laboratories Inc.
1. TEST EQUIPMENT REQUIRED
1. Cassette Torque Meter: For take-up check: 0 ~ 100 g-cm (0 ~ 1.4 02-inch)
For fast forward & rewind torque checks: 0 ~ 160 g-cm (0 ~ 2.2 02-inch) |
NOTE: When ordering Cassette Torque Meter, allow for longer delivery time that is required for it.
2. Spring scale: For Pinch Roller pressure check: 0 ~ 500 g (1.1 Ibs)
3. Wow/flutter meter: MEGURO DENPA SOKKI K.K., Model MK-668A :
4, Frequency counter: Digital type, capable of 10 Hz to 100 kHz indication. fore
5. AF oscillator: 10 Hz ~ 100 kHz
6. AC Voltmeter: 0.1 mV ~ 300V
7. Attenuator: General Purpose
8. Distortion analyzer: Basic frequency 400 Hz/1 kHz
9. Oscilloscope: General Purpose
10. Band-pass filter: 1 kHz narrow band-pass type
11. Test load resistor: Non inductive type 8 ohm/1 W
12. Plastic alignment tool:
13. Head demagnetizer: TEAC E-3 or equivalent 5
14. Cleaner: TEAC TZ-261 Tape Recorder Cleaner kit or pure alcohol §
15. Oil: TEAC TZ-255 Oil kit or equivalent
Fig. 1-1 Plastic Alignment Too!

2.
SPECIFICATIONS
&
SERVICE
DATA
SPECIFICATIONS
———____—CO
TTT
Track System
3 Heads
Type of Tape
Tape Speed
Inputs
(level and impedance)
Outputs
(level and load impedance)
Equalization
Head Configuration
Motor
Bias Frequency
Operating Position
Power Requirements
Power Consumption
Weight
* Pursuant to DIN Standards
TEAC TEST TAPE
REMARKS:
0
dB
=
DIN
Reference
level
(333
Hz)
For
tape
speed
&
wow/flutter
test
MTT-111:
For
Playback
method
3,000
Hz/—10
dB
NOTE:
The
TEAC
test
tapes
require
longer
delivery
time
MTT-501:
For
record/Playback
method
(blank
tape):
than
normal
parts.
MTT-150:
For
Dolby
level
calibration
Dolby
B-type
tone
(400
Hz
tone),
200
nWb/m
MTT-316:
For
frequency
response
test
for
EQ:
CrO2
3,180 us + 70 ys
315
Hz/—4
dB,
31.5
Hz
~
14
kHz/—24
dB
MTT-216:
For
frequency
response
test
for
EQ: NORMAL
3,180 ps + 120 us
315
Hz/—4
dB,
31.5
Hz
~
14
kHz/—24
dB
4-track, 2-channel stereo
Erase, Record and Playback
Cassette
tape,
C-60
and
C-90
(Philips
type)
4.8 cm/s (1-7/8 ips)
MIC:
Specified
input
level:
—57
dB
(1.09
mV)/10
kohms
Min.
input
level:
—67
dB
(346
uV)
LINE
IN:
Specified
input
level:
—9
dB
(275
mV)/50
kohms
Min.
input
level:
—19
dB
(86.9
mV)
DIN
IN*:
Min.
input
level:
—35
dB
(13.8
mV)
OUTPUT:
Max.
output
level:
—2.5
dB
(580
mV)/SO
kohms
Specified
output
level:
—5
dB
(436
mV)
Headphones:
Specified
output
level:
—21
dB
(69
mV)/8
ohms
CrO2: 3180 us + 70 us
NORMAL: 3180 us + 120 us
1/2-track, 1-channe] Erase Head
1/4-track,
2-channel
Dual-gap
Record
and
Playback
Heads
FG Servo Controlled DC Motor
100 kHz
Horizontal
100/117/220/240
V
AC,
50/60
Hz
(General
Export
Models)
117
V
AC,
60
Hz
(U.S.A./Canada
Models)
220 V AC, 50 Hz (Europe Model)
240
V
AC,
50
Hz
(U.K./Australia
Models)
12W (U.S.A. Model)
11W (All except U.S.A. Model)
7.5 kg (16.5 Ibs) net
7.8
kg
(17.2
Ibs)
net
(General
Export
Models
for
Limited
Area)
For
playback
performance
alignment
For
record
performance
alignment
(blank
tape)
MTT-506
or
equivalent:
For
BIAS
&
EQ:
CrO2
MTT-501
or
equivalent:
For
BIAS
&
EQ:
NORMAL
Fig. 2-1 - TEAC Test Tape

SERVICE DATA
Mechanical
Tape Speed Deviation
Tape Speed Drift
Wow and Flutter
Pinch Roller Pressure
Reel Torque (Take Up)
Reel Torque (Back Tension)
Fast Winding Time
Electrical
Frequency Response
Signal to Noise Ratio
Erase Efficiency
Channel Separation
Crosstalk between Adjacent Tracks
Total Harmonic Distortion
3,000 Hz + 45 Hz
45 Hz
Playback: 0.10% (WRMS)
Record/Playback: 0.25% (RMS)
400 g + 50 g (12.3 to 15.9 0z)
Play and Rec/Play: 40 to 60 g-cm (0.6 to 0.8 oz-inch)
Fast Forward: 80 to 150 g-cm (1.1 to 2.1 oz-inch)
Rewind: 100 to 150 g-cm (1.4 to 2.1 oz-inch)
Play and Rec/Play: 3 to 8 g-cm (0.04 to 0.11 oz-inch)
90 seconds for C-60
Refer to frequency response limits charts on page 12 and 16.
Playback method: 47 dB min.
Record/Playback method: BIAS/EQ, CrO2 45 dB min.
BIAS/EQ, NORMAL 44 dB min.
With Dolby Noise Reduction used for recording and playback, S/N
ratio is improved by up to 5 dB at 1 kHz and up to 10 dB at frequencies
over 5 kHz.
65 dB min.
30 dB min. (at 1 kHz)
40 dB min. (at 125 kHz)
BIAS/EQ, CrO:2 : 2.2% (max.)
BIAS/EQ, NORMAL: 2.5% (max.)
NOTE: e Improvements may result in Specifications and Service Data changes.
e dB values in the Specifications and Service Data are based on 0 dB = 0.775 V. In case the AC Voltmeter
being used is calibrated to some other standard such as 0 dB= 1 V etc, please use the voltage values
given in parentheses as the test values.
17-1/2“(444 mm)
16-3/16'(410mm)
11-1316'(300mm)
r
i
t
t
1
t
!
1
1
1
i
4
1
1
L
FEEEEER coe ©
~1/4"(IS8mm)
bee eee eo ee
T-1038~I
* Broken line indicates General Export Models for Limited Areas.
Fig.2-2 Dimensions

3. PARTS LOCATION
VOLTAGE SELECTOR PCB Ass’y
(for
General
Export
Models)
IN/OUTPUT
PCB
Ass’y
Power
Transformer
REC AND PLAY
MECHANISM :
PCB Ass’y AMPL. PCB Ass y
Damper
Holder
Ass’y
DC
Motor
Ass’y
Fig. 3-1 Top View
Cassette Holder Ass'y Counter Ass'y
Supply Take-up
Reel
Table
Ass'y
VU
Meters
Reel Table Ass'y
Erase Head REC-PLAY Head Pinch Roller Ass'y
Fig. 3-2 Front View

4.
ILLUSTRATED
DISASSEMBLY
PROCEDURES
GENERAL NOTES
1. Disassemble in number-order.
.
Use
the
proper
tools.
Demagnetize
the
tools
before
use.
3,
When
mounting
or
removing
a
spring,
check
the
posi-
tion
(direction)
of
the
anchor
or
hook.
The
wrong
position may change the tension.
4.
When
reassembling,
don’t
forget
to
reinstall
all
hard-
ware such as springs and washers etc.
5.
To
check
the
shape
of
assembling
hardware
(screws,
etc.)
see
ASSEMBLING
HARDWARE
CODING
LIST
in the parts list.
4-1. EXTERNAL PARTS
4-M4x6
(Round Washer Head)
BM3x6
Fig. 4-1 External Parts
4-2,
CASSETTE
DAMPER
(DAMPER
CORD
STRINGING)
Preparation
Remove in number-order.
1. Fig.4-1, 2 and 3.
T1742
Fig. 4-2 Cassette Damper
4-3. CASSETTE HOLDER ASS’Y
Preparation
Remove in number-order.
1. Fig.4-1, 1 -thru-8.
2. Fig. 4-2, 1. ee a
a Se ‘
ee a
Re a
8 pT.
W4x10.25
a CE WW 24x10.5
W4x10.5,
. oo ee tiga
Pe,
Dyk mS
oe |S _
2-PSA Bae 6
M2.644 Y
Fig. 4-3 Cassette Holder Ass'y

44. HEADS AND PINCH ROLLER
Preparation
Remove in number-order.
1. Fig. 4-1, 1-thru-8.
2-Sw 2
2-8 o® Y 5
M2xi2 ; Pr ®
Ye
We
SW 42
BM2xi2
Fig.4-4 Head/Pinch Roller
ERASE HEAD REC~PLAY HEAD
unt oT iy
NO) aT
> YEL
3G OYBLU
ie ° a WHT
WHT WHT
T1744
DD
Fig. 4-5 Head Wiring Diagram
NOTE: 1. After replacing the head, always adjust the head
alignment, especially the Record/Playback
Head’s azimuth and then secure the screws and/
or the nut with a drop of locking paint.
2. Connect the wires to the head terminal pins
quickly to prevent breaking of internal wires of
the head due to overheating.
3, After replacement, always clean the driving sur-
. faces of the Pinch Roller with the TEAC TZ-
261B Rubber Cleaner or with pure alcohol,
then proceed directly to the PINCH ROLLER
PRESSURE adjustment section.
4-5. REEL TABLES
Preparation
Remove in number-order.
1. Fig.4-1, 1 -thru- 8.
2. Fig.4-2, 1.
3. Fig. 4-3, 1 -thru- 13.
4
3 £ -
5 . aa <
(\O" 7 ee B15x84x10.25
2-€ 012 EN \ Za
6.
/ x?
ST x10.5
be) SS
Fig. 4-6 Reel Tables
4-6. BRAKE PLATE ASS’Y
Preparation
Remove in number-order.
1. Fig.4-1, 1 -thru- 8.
2. Fig.4-2, 1.
3. Fig. 4-3, 1 -thru- 13.
Eeae
W $3X10.25
3
Fig.4-7 Brake Plate Ass’y

4-7, MOTOR
Preparation
Remove in number-order.
1. Fig. 4-1, 2 and 3.
Fig. 4-8 Motor
NOTE: 1. When re-assembling, clean the pulley and the
Belt with TEAC TZ-261 Cleaner kit (“A” for
the Pulley, ““B” for the Belt) or with pure
alcohol.
2. Take off or remount the Motor Ass’y taking
care not to scratch or otherwise damage the
Motor Pulley.
3. When re-attaching the Drive Belt to the Pulley
do not twist or stretch the belt.
4-8. CAPSTAN DRIVE ASS’Y
Preparation
Remove in number-order.
1. Fig. 4-1, 1-thru- 3.
2. Fig. 4-8, 1 -thru-3.
Fig. 4-9 Capstan Drive Ass’y
4-9. LUBRICATION
Refer to Fig. 4-9.
Lubrication should be generally done at about every 1,000
hours of operating time of the tape deck. Use high quality
oil for this purpose.
For efficient oiling, it is recommended that lubrication be
done after nearly 1 hour of idling of the deck and while it
is still warm.
Normally, it is necessary to lubricate only the areas de-
scribed below.
1. Apply a drop of a light machine oil of good quality
(e.g.: TEAC TZ255) with an oil applicator to the shaft
of the Flywheel and spread oil evenly over the shaft
with a flannel cloth. After installing the Flywheel, be
sure to clean the tape moving portion of shaft with
TEAC TZ-261 A Head Cleaner or with pure alcohol.
2. Apply a drop of the proper oil in the same way as
above to the innermost area of capstan shaft (next to
the Flywheel).
3. Apply a film of light grease to the well of the Flywheel
Bearing.
4-10. IDLER/TENSION PULLEY ASS’Y
Preparation
Remove in number-order.
1. Fig. 4-1, 2 and 3.
2. Fig. 4-8, 1-thru-3.
3. Fig. 4-9, 1-thru-4.
Fig. 4-10 Idler/Tension Pulley Ass’y

5.
MECHANICAL
CHECKS
AND
ADJUSTMENTS
5-1. TAKE-UP AND SUPPLY TORQUE
Specifications:
—
5-3. PINCH ROLLER PRESSURE
Take-up: 40 to 60 g-cm (0.6 to 0.8 oz-inch)
Supply: 3 to 8 g-cm (0.04 to 0.11 oz-inch)
Depress POWER Switch ON to apply AC power.
Load the cassette torque meter (for take-up and supply
torques).
Place the deck in the play mode and read the pointer
indication on the right-hand dial scale to check the
take-up torque.
While continuously playing, read the pointer indication
on the left-hand dial scale to check the supply torque.
If the reading(s) are out of the specified range, clean
the driving surfaces of the reel table ass’y and all other
driving parts relative to the take-up and supply torque
function with the TEAC TZ-261B rubber cleaner or
which pure alcohol.
If the above cleaning is ineffective for torque correc-
tion, replace the Reel Table Ass’y.
5-2.
FAST
FORWARD
&
REWIND
TORQUE
Specifications:
Fast Forward torque: 80 to 150 g-cm
(1.1 to 2.1 oz-inch)
Rewind
torque:
100
to
150
g-cm
(1.4
to
2.1
oz-inch)
Depress
POWER
Switch
ON
to
apply
AC
power.
Load
the
Cassette
Torque
Meter
(for
fast
forward
and
rewind
torque).
Place
the
deck
in
the
FF
or
REW
mode
and
read
the
pointer
indication
on
the
dial
scale.
The
Meter
should
indicate
a
torque
of
80
to
150
g-cm
(1.1
to
2.1
oz-inch)
as
Fast
Forward
Torque
and 100
to
150
g-cm
(1.4
to
2.1
oz-inch)
as
Rewind
Torque.
If
the
indication
is
out
of
specified
range,
clean
the
driving
surfaces
of
the
Reel
Table
Ass’y
and
all
other
driving
parts
relative
to
the
Fast
Forward
&
Rewind
torque
function
with
the
TEAC
TZ-261B
Rubber
Cleaner
or
with
pure
alcohol.
—
“If
the
above
cleaning
is
ineffective
for
the
torque
correction,
replace
the
driving
parts
relative
to
these
torques.
Fig. 5-1 Cassette Torque Meter
Specification: 400g + 50 g (12.3 to 15.9 02)
RWNe
Remove Front Panel, then Cassette Holder Ass’y.
Depress POWER Switch ON to apply AC power.
Place the deck in the PLAY mode with no tape loaded.
Attach the spring scale to the Pinch Roller shaft as
shown.
Gently draw the Pinch Roller away from the Capstan
shaft in a directly downward direction until the Cap-
stan
shaft
and
the
Pinch
Roller
are
completely
sepa-
rated,
Gradually
return
the
scale
back
until
the
Pinch
Roller
just
begins
to
rotate.
The
scale
should
then
be
reading
approximately
400
g
+
50
g
(12.3
to
15.9
oz).
If the reading is out of specified range, replace the
Pinch Roller Ass’y or the Pressure Spring or adjust the
Spring Arm as shown.
Bend here
to adjust
Fig.
5-2
Pinch
Roller
Pressure
Measurement

5-4. TAPE SPEED/WOW AND FLUTTER
Specifications:
Tape Speed Deviation: 3,000 Hz+ 45 Hz
Tape Speed Drift: 45 Hz
Wow and Flutter: Playback: 0.10% (WRMS)
Record/Playback:
0.25% (RMS)
NOTE: 1. Before performing this adjustment, clean all
parts in the tape path, particularly the Capstan,
the Pinch Roller and the Heads with the appro-
priate liquid from the TEAC TZ-261 Cleaner
Kit or with pure alcohol.
2. Wow and flutter should be checked in two
ways; Playback only and Record/Playback
methods. First correct tape speed and wow and
flutter using the playback only method. Then
measure wow and flutter using record and play-
back method.
3. As the measured results may vary with respect
to location on tape at which it was taken, three
points — at beginning, middle and near the end
of the tape — should be measured.
54-1. TAPE SPEED
1. Connect test equipment to the deck, except the AF
oscillator, as shown in Fig. 5-3.
2. Set the EQ switch to NORMAL position, and then load
and play a TEAC MTT-111 test tape (3,000 Hz signal
is recorded),
3. Adjust the control located at the center of the Motor
for reading of 3,000 Hz + 10 Hz on the frequency
counter,
(NOTE: This tape speed setting should be done after
approx, 30 seconds of operating time of the deck).
4. Then, verify the reading on the frequency counter as
within the specified range of 3,000 Hz + 45 Hz, and
the tape speed drift is within 45 Hz at any portion of
the tape run.
5. If the tape speed is extremely out of the specification,
check the Pinch Roller pressure and the tape driving
function for correction, and make sure the tape path
is clean.
5-4-2, WOW AND FLUTTER
After making the tape speed measurement, perform the
wow and flutter test using the Playback Method and the
Record /Playback Method successively.
PLAYBACK METHOD
1. Play the MTT-111 test tape.
2. Read the indication on the wow and flutter meter.
3. The wow and flutter value should be 0.10% WRMS,
max.
10
FREQUENCY COUNTER
wow & FLUTTER METER
DECK
under TEST ¢
+463
Fig. 5-3 Tape Speed/Wow & Flutter Measurement Setup
,
TAPE SPEED ADJ. ¥
f 3,000Hz + 10Hz
OA aude wr
T-1679
Fig. 5-4 Tape Speed Adjustment Location
4. If the wow and flutter is out of specification, check the
Pinch Roller pressure and the take-up torque, see that
the tape path is clean, and that the Capstan Belt is not
stretched or oily.
5. If the above checks are ineffective for excessive wow
and flutter correction, repair or replace the Pinch
Roller, the Capstan Belt and/or any other defective
parts.
RECORD/PLAYBACK METHOD
NOTE: When using this method, adopt the maximum wow
and flutter value obtained by repeated play and
stop modes of operation. This operation is neces-
sary to make sure wow and flutter content be-
tween record and playback will not be in phase to
create a false reading.
1. Connect test equipment to the deck as shown in Fig.
5-3.
2. Set LINE or RECORD controls on the deck to obtain
convenient input levels.
3.
Load
a
TEAC
MTT-SO1
test
tape
(blank)
and
set
the
BIAS/EQ switches in the NORMAL positions.
Apply and record a 3,000 Hz signal.
Rewind and play this recorded section.
Read the indication on the wow and flutter meter.
The wow and flutter value should be 0.25% RMS max.
If the measured value is. out of specification, repair
using the same methods as stated in steps 4 — 5 in the
Playback Method procedure.
On Nn