Teac C-3X User manual

TEAC,
SERVICE MANUAL
C-3X
Stereo Cassette Deck

3X
1
SPECIFICATIONS
AND
SERVICE
DATA
NOTES:
1.
Improvements
may
result
in
changes
in
specifications
and
service
data.
2.
04B
is
referenced
to
0.775
V
in
this
manual
unless
otherwise
specified.
3.
All
the
electrical
numeral
values
are
for
STANDARD
speed
unless otherwise specified.
SPECIFICATIONS
Track System 4-track, 2-channel stereo
Heads 3: Erase, record and playback
Type
of
Tape
Cassette
tape,
C-60
and
C-90
(Philips
type)
Tape
Speed
4.75
cm/s
(1-7/8
ips),
9.5
cm/s
(3-3/4
ips)
Input (level and impedance)
MIC:
Specified
input
level:
—57
dB
(1.09
mV)/10k
ohms
Minimum input level: —67 dB (346 nV)
LINE
IN:
Specified
input
level:
—9
dB
(275
mV)/50k
ohms
Minimum input level: -19 dB (86.9 mV)
Output (level and impedance)
OUTPUT:
Maximum
output
level:
2.5
dB
(581
mV)/S0k
ohms
Specified output level: —5 dB (436 mV)
PHONES:
Specified
output
level:
-15.8
dB
(126
mV)/8
ohms
Equalization
HIGH STANDARD
METAL
3180
us
+35
us
3180
us
+
70
ps
Co(CrO2)
3180
us
+
35
us
3180
us
+
70
us
NORMAL
|
3180
us+
50
us
3180
us
+
120
us
Head Configuration
1/2-track, 1-channel erase head
1/4-track,
2-channel
record
head
and
playback
head
in
a
single
housing
Motors 1 DC servo capstan motor
1 DC reel motor
Bias Frequency 100 kHz +5 kHz
Operation Position Horizontal
Power Requirements
100/117/220/240
V
AC,
50/60
Hz,
41
W(General
export
model)
117
V
AC,
60
Hz,
41
W(U.S.A/Canada
model)
220
V
AC,
50
Hz,
41
W(Europe
model)
240
V
AC,
50
Hz,41
W(U.K./Australia
model)
Weight 9 kg (19-3/16 Ibs.) net
Dimensions See Fig. 3-2
Noise
Reduction
System
and
Headroom
Extension
System
manufactured
under
license
from
Dolby
Laboratories
Licensing
Corporation.
“Dolby’
and
the
double-D
symbol
are
trademarks
of
Dolby
Laboratories
Licensing
Corporation.
SERVICE DATA
MECHANICAL
Tape Speed Deviation 3,000 Hz +45 Hz
Tape Speed Drift 30 Hz
Wow and Flutter
HIGH STANDARD
Playback 0.065% (WRMS) 0.08% (WRMs)
Record/playback | 0.18% (RMS) 0.25% (RMS)
Pinch
Roller
Pressure
390
g
to
490
g
(13.8
oz
to
17.3
02.)
Reel
Torque
(at
STANDARD
speed)
Take-up:
45
to
65
g-cm
(0.625
to
0.903
oz-inch)
Supply:
3
to
8
g-cm
(0.0417
to
0.111
oz-inch)
F.F.&
REW:
90
to
160
g-cm
(1.25
to
2.22
oz-inch)
Fast
Winding
Time
90
seconds
for
MTT-501
(C-60)
ELECTRICAL
Frequency Response
See Figs. 5-9 to 5-13.
Signal-to-noise Ratio
Playback
Better
than:
HIGH
STANDARD
METAL,
Co(CrO,)
55
dB
52dB
NORMAL
53
dB 48
dB
Overall
Better
than:
HIGH
STANDARD
METAL,
Co(Cr0.)
49
dB
48
dB
NORMAL
46
dB
45
dB
S/N
is
improved
by
5
dB
at
1
kHz
and
10
dB
above
5
kHz
when
Dolby
NR*
is
used.
Erase
Efficiency
65
dB
min.
at
1
kHz
(measured
with
input
10
dB
higher
than
the
specified
input
level)
Channel
Separation
35 dB
min.
at
1
kHz
Adjacent
Track
Crosstalk
40
dB
min.
at
125
Hz
Total
Harmonic
Distortion
2.0%
or
less
with
NORMAL,
Co(Cr02)
and METAL tapes
ldbx
noise
reduction
system
made
under
license
from
dbx,
Incorpo-
rated,
The
word
dbx’
and
the
Symbol
are
trademarks
of
dbx,
incorporated.
CAUTION
must
always
be
replaced
with
identical
components
-
refer
to
the
TEAC
Parts
List
and
ensure
exact
replacement.
AsParts
marked
with
this
sign
are
safety
critical
components.
They}

2 PARTS LOCATION
POWER REC/PLAY
TRANSFORMER AMPL, PCB ASSY
JOINT PCB ‘A
REEL
MOTOR
CAPSTAN
MOTOR
LEVER
SWITCH
PCB
ASSY
Fig. 2-1
SUPPLY TAKE-UP COUNTER REECMOTOR
REEL TABLE REEL TABLE
ERASE HEAD
TENSION ARM PINCH ROLLER
REC/PLAY HEAD CASSETTE HOLDER CAPSTAN MOTOR
FAST FORWARD SOLENOID
HEAD BASE SOLENOID
PINCH ROLLER SOLENOID
Fig, 2-2 Fig. 2-3

LIMITED AREA
3
REMOVAL
OF
EXTERNAL
COMPONENTS
Disassemble
in
number-order
Fig. 3-2 Dimensions
C-3X
sil
aires
Fig. 3-1

recess
4 MECHANICAL ADJUSTMENTS AND CHECKS
Note: All checks and adjustments are made with the SPEED switch
set to STANDARD, unless otherwise indicated.
4-1 REEL TORQUE 4-3 HEAD BASE PLATE POSITIONING
1. Load the cassette torque meter on the deck and read the pointer
indication on the dial scale for each tape transport operation.
The measured torque should be within the following values:
Take-up: 45 to 65 g-cm (0.62 to 0.90 oz-inch)
Supply: 3 to 8 g-cm (0.042 to 0.11 oz-inch)
F.F.and REW: 90 to 160 g-cm (1.25 to 2.22 oz-inch)
4-2 PINCH ROLLER PRESSURE
1, With the cassette holder shut and no tape loaded, put the deck in
PLAY mode.
2. Hook a spring scale on the top of the pinch roller assembly plate,
as shown in the illustration,
3. Pull the scale down until there is sufficient force to separate the
pinch roller from the capstan shaft,
4. Ease pressure until the pinch roller makes just enough contact
with the capstan shaft so that the pinch roller just begins to turn.
At this point, note the reading an the scale. It should be from
390 g to 490 g (13.8 oz. to 17.3 02.)
|. If the pressure is not within the prescribed specifications, it may
be adjusted by first removing the pinch roller spring from the
pinch roller assembly and then bending the spring as shown in
the illustration.
a
stronger
stronger
weaker
Fig. 4-1
1, Set the deck in the PLAY mode.
2. Push the head base plate by hand in the direction of the arrow
and check that the head base plate and the stopper portion of
‘the mechanism chassis make contact.
3. If there is any clearance, loosen the two screws on the head base
plate solenoid and reposition the solenoid until the clearance is
eliminated.
Head base plate
ot
Stopper portion of
There
should
be
mechanical
no
clearance
at
chassis
this
point,
Push by hand 1-1884-1
when in PLAY mode Peers
Fig. 4-2
Screws
Head Base
Solenoid
Fig. 4-3 Head base solenoid location
4-4 CAPSTAN ASSEMBLY THRUST
1, Turn the thrust adjusting screw so that thrust of the. capstan
shaft is within 0.05 mm to 0.15 mm.
Thrust play
0.05 mm to 0.15 mm
Thrust
adjusting
screw
Flywheel
Fig. 4-4

4-5 TAPE SPEED
STANDARD speed
1.
Connect
a
frequency
counter
to
the
deck
as
shown
in
Fig.
4-5.
2.
Play
a
tape
for
about
five
minutes
to
warm
up
the
deck,
then
load
a
TEAC
MTT-111
test
tape
containing
a
3000-Hz
test
tone
and
play
the
test
tape
from
the
beginning.
3.
While
the
tape
is
playing,
use
a
common
slotted
screwdriver
with
the
handle
completely
insulated
from
the
blade,
and
adjust
the
control
on
the
MOTOR
PCB
(as
far
as
possible)
for
a
reading
of
3000
Hz
(Spec.
3000
Hz
+5
Hz)
on
the
frequency
counter.
4,
Play
the
tape
at
the
beginning
and
at
the
end,
and
check
that
the
speed
deviation
is
within
the
prescribed
limits
by
observing
that
the
reading
on
the
frequency
counter
never
deviates
more
than
+45
Hz
from
3000
Hz,
nor
drifts
more
than
30
Hz
at
any
given
time.
HIGH speed
5.
Set
the
deck
to
HIGH
speed
and
follow
all
the
procedures
described
above.
Since
the
speed
is
doubled,
all
the
values
described
in
the
preceding
steps
are
also
doubled
to
be
com-
patible.
6.
If
the
tape
speed
is
not
within
the
prescribed
specifications,
check
the
pinch
roller
pressure
and
the
tape
transport
mechan-
ism
for
any
abnormality,
and
make
sure
the
tape
path
is
clean.
Frequency Counter
—
g 00
Oscillator
Wow &
Flutter Meter
DECK
(under TEST{—
TAY
LINE IN
Q0°
JURY
ouTPUT
Fig. 45
Fig. 4-6 Tape speed adjustment location
4-6 WOW AND FLUTTER
Note: These measurements should be made at the beginning, middle,
and the end of the tape.
1) PLAYBACK
STANDARD Speed
1.
Connect
a
wow-and-flutter
meter
to
the
deck
as
shown
in
Fig.
4-5.
2. Load and play a TEAC MTT-111 test tape.
3.
Check
that
the
reading
on
the
wow-and-flutter
meter
is
within
0.08%
(WRMS).
2) SIMULTANEOUS RECORD/PLAYBACK METHOD
STANDARD Speed
4.
Load
a
TEAC
MTT-501
test
tape
(blank)
and
record
a
3000-Hz
signal.
5. With the MONITOR switch in the TAPE position, note the read-
ing on the wow-and-flutter meter, it should not be more than
0.25% (RMS).
HIGH Speed
6. Repeat the above procedures with the deck set to HIGH speed.
The wow and flutter should not be more than 0.18% (RMS).
3)
NON-SIMULTANEOUS
RECORD/PLAYBACK
METHOD
STANDARD Speed
7.
Rewind
the
tape
to
the
beginning
of
the
recorded
section
pre-
viously
made
in
step
4,
and
play
it
at
STANDARD
speed.
8. The wow and flutter should not be more than 0.25% (RMS). ~
HIGH Speed
9.
Rewind
the
tape
to
the
beginning
of
the
portion
previously
recorded
in
and
play
it
at
HIGH
speed.
The
wow
and
flutter
should
not
be
more
than
0.18%
(RMS).
4-7
MICROSWITCH
(A)
ASSEMBLY
CLEARANCE
1.
Insert
a
blank
cassette
and
close
the
cassette
holder.
2. Loosen the two screws on the microswitch (A).
3.
Move
the
switch
so
that
actuator
of
the
switch
contracts
the
safety
lever.
4.
Adjust
the
switch
position
to
obtain
a
clearance
of
between
0.1
mm
to
0.3
mm.
5. Retighten the screws.

Safety lever
Blank cassette
T1856
0.1 mm to 0.3 mm clearance
Actuator
ale
Safety lever Bent tip of
switch bracket
Fig. 4.7
4-8 MICROSWITCH (B) ASSEMBLY CLEARANCE
1. Push the EJECT button to open the cassette holder.
2, Loosen the two screws on the microswitch (B),
3. Move the switch so that switch actuator contacts the bent pro-
jecting portion of the eject lever.
4. Adjust the switch position to obtain a clearance of approximate-
ly 1mm.
5, Retighten the screws,
Clearance of
‘approx. 1 mm|
Switch Housing
Fig. 4-8
4-9 LUBRICATION
Lubrication is only required when parts are replaced. For this pur-
pose, use the oil and grease specified below.
Oil: TEAC spindle oil (from TEAC TZ-255 oil kit), Mobil
D.T.E. Oil Light, or equivalent
Grease: ORE-LUBE G1/3 or equivalent
1. Apply a drop of oil with an oil applicator to a point about 1/3
the way down the shaft (from the free end) of the flywheel, then
insert the shaft into the capstan housing.
2. Apply a suitable amount of light grease to the well of the fly-
wheel bearing.
Capstan Flywheel Assy
Well of
Flywheel Bearing
Capstan Shaft
Apply a drop of oil here.
Capstan Housing
Fig. 4.9
4-10 VOLTAGE SELECTION
(FOR GENERAL EXPORT MODELS)
1. Always disconnect the power line cord before making these
adjustments.
2. Remove the top cover of the deck by removing the screws from
the sides.
3. Locate the voltage selector, shown in the illustration (in front of
the power transformer).
4. Loosen the two screws in the shorting bar and move the bar so
that it jumpers the opposing terminals marked with the required
voltage (100, 117, 220 or 240).
5. Retighten the screws and replace the top cover.
4-11 AC POWER LINE FREQUENCY
Since the C-3X uses a DC servo motor, 50 Hz or 60 Hz operation is
permitted without any change in power line frequency.
Shorting Bar
Fig. 4-10

|
oa
4
|
5
ELECTRICAL
ADJUSTMENTS
AND
CHECKS
PRECAUTIONS
1. Before beginning any checks or adjustments, clean and demag-
netize the entire tape path.
2. Make sure the deck is properly set for the voltage in your
locality.
3. In general, adjustments and checks are done in the order of L-ch
then R-ch. Double REF. NOs. and test point designations indi-
cate L-ch/R-ch.
(Example: R11/R21)
4. For this deck, 0 dB is referenced to 0.775 V. If you are using an
AC voltmeter which references 0 dB to 1V, appropriate com-
pensation should be made.
5, The AC voltmeter used in the procedures must have an input
impedance of 1M ohms or more.
6. Note the “Deck settings” at the top of each chart. These settings
must be used for all the checks in each chart unless explicitly
stated otherwise.
—70 dB or more .. . What does it mean?
In reference to some specifications, you may come across an expres-
sion like: “—70 dB or more”. This means that the lower the value
of this specification, the greater the absolute value of the specifica-
tion and the better the performance of the deck. For instance, a
noise floor of —76 dB is better than —70 dB, because this means
that the level of noise is lower. So in this case, “—70 dB or more”
means at least as good a value as —70 dB and maybe even better,
ie., -71 dB,
OSCILLOSCOPE
OSCILLATOR oistoRTION ANALYZER
amp SPKR
=r
AC Voltmeter
4kHz FILTER
ATTENUATOR si
DECK c
L
a %
errs tJ under TEST |=
LINE IN
rrr
OUTPUT
Fig. 5-1 Basic test setup
OSCILLOSCOPE
AMP SPKR
1
DECK
under TEST
L A=
}__] 0°
AC Voltmeter.
OUTPUT 1-83
Fig. 5-2 Test setup for azimuth check
REC-PLAY Head
Height/Tilt
Adjusting Screw
Azimuth
Adjusting
Nut
T-1769
Fig. 5-3 Azimuth adj, nut location

Deck settings: TEAC test tapes:
MONITOR sw.: TAPE MTT-150: For Dolby level calibration
NR SYSTEM sw.: OUT MTT-316: For playback frequency response
SPEED sw.: STANDARD check for METAL, Co(Cr0,)
5-1 PLAYBACK PERFORMANCE EQ sw.: METAL MTT-216: For playback response check for NORMAL
MEASURING
ADJUST —_|POINT:
ITEM SETTING INPUT SIGNAL, (or CHECK) REMARKS
RESULT
Conn.: Fig. 5-2 OUTPUT:
1,
REC/PLAY
head
Azimuth
nut
of
|
@
Phase:
about
0°
azimuth OUTPUT cont.: convenient MTT-316 (12.5 kHz) R-P heads ‘on ‘scope (Fig. 5-4)
output level position (Fig, 5-3) Max. output on
OUTPUT: |
Phase: 45° min.
2. Phase shift Same as above MTT-316 Check (315 Hz)
90° min.
(12.5 kHz)
- - TP1/TP2
MTT-150 R11/R21 2.5 dB (581 mV)
Spec. setting of
OUTPUT: OUTPUT cont.
3. Specified output zs MTT-180. OUTPUT cont, 1° 5 dB (436 mV) |e Spec. output
level
PEAK LEVEL meter
level
4, PEAK LEVEL meter - MTT-150 RIZ/R22 eA
EQ: METAL, Co(CrO,)
Adjust for 10 kHz to-be the output:
same level as ref. signal MTT-316 R10/R20 Fig. 5-9
(315 Hz)
5. Frequency response | ~~ - ----~~~~----4~-----------}-------- -- =
OUTPUT: At 10 kHz,
, should be 3 dB to 6 d8|
EQ: NORMAL MTT-316 Check higher than measured
in above step.
SPEED: STANDARD and __| Fully-erased tape: OUTPUT:
HIGH (Use bulk tape eraser) {82.48 min. ist0)] Ratio of spec.
6. Signal-to-noise ratio |EQ: METAL . . METAL . fe 55 dB min. (HI) output of
Co(CrO) . .MTT-5061 Check 48 dB min. (STD)| —5 dB to noise
NORMAL )IMTT-501 = 53 aB min, (Ht)
PHONES:
7. Headphone output | conn: Fig, 5-5 MTT-150 Check ~15.8 dB 43 dB 8 ohm load
(89.0 mV to 178 mV)
AC Voltmeter
f=}
0° (IN PHASE) 45° g0° 180°
Fig. 5-4 Confirming phase relationship
DECK under TEST
PHONES
one
Fig. 5-5 Test setup for headphone check

Deck setting:
REC-PAUSE mode
MONITOR sw.: SOURCE
NR SYSTEM sw.: OUT
|
INPUT
sw.:
LINE
5-2
MONITOR
PERFORMANCE
QUTPUT
cont.:
Specified
position
(item
3)
ly
MEASURING
ADJusT | POINT:
ITem
SETTING
INPUT
SIGNAL
iaonek
REMARKS
RESULT
:
Mic:
OUTPUT:
ie
Se
oe
ee
ice
400
Hz/-67
dB
Check
—5 dB
43
dB
MIG
rain:
Ineut
1
(346
uv)
(308
mV
to
615
mV)
8.
Min.
input
level
isioreeccd
irene
INPUT
sw.:
LINE
400
Hz/—19
dB
Check
—5
dB
43
dB
nee
(86.9
mv)
(308
mV
to
615
mv)|
'"P'
‘i
LINE
IN:
Specified
set-
:
RECORD
cont,
|
OUTPUT:
F
-
400
Hz/—9
dB
3
ting
of
RE-
(6
(LR)
—5
dB
(436
mV)
ee,
2,
EINE
epeeiteed.npatt
LINE
IN:
DOLBY
TP
(TP1/TP2);
=
400
Hz/-9
dB
Check
-2.5d8
£0.5dB
(275
mV)
(648
mV
t0
615
mV)
ge ECORD or OUTPUT controls,
after establishing their setting as ab
i
LINE
IN:
:
:
10.
PEAK
LEVEL
PEAK
LEVEL
meter:
i
=
400
Hz/—9
dB
Check
i
:
meter
400
He
dB
#1
dB
:
LINE
IN:
‘
a.
;
11,
“TEST
IN”
INPUT
sw.:
TEST
400
Hz/—29
4B
Check
atl
i
(27.5
mV)
L
>
U
Deck
settings:
:
MONITOR
sw.:
TAPE
}
NR
SYSTEM
sw.:
OUT
INPUT sw.: LINE
SPEED sw.: STANDARD TEAC test tapes:
ADJUST/PRE-SET
sw.:
PRE-SET
MTT-5061:
For
record
test
with
Co(Cr0.)
OUTPUT
cont.:
Specified
position
(item
3)
|
MTT-501:
For
record
test
with
NORMAL
5-3
RECORDING
PERFORMANCE
RECORD
cont.(L/R):
Specified
position
(item
9)
METAL:
For
record
test
with
METAL
MEASURING
ADJUST | POINT:
ITEM
SETTING
INPUT
SIGNAL
a
eneeK)
REMARKS.
RESULT
NEN:
BIAS
TRAP
TP
12.
BIAS
trap
Record-pause
mode
Ae
nek
L104/L.204
(TP3/TP4):
a
Min.
reading
LINE IN:
OUTPUT:
BIAS, EQ: METAL “AOOHz & 10 kHz
Tape:
METAL
alternately/—42aB
|
R18/R25
Neatly.
eciuel
eve
eienvl
at
both
frequencies
Hl LINE IN
i
:
:
ouTPuT:
:
13,
Record
bias
BIAS,
EQ:
Co(CrO9)
400
Hz
&
10
kHz
|
Tape!
MTT-5061
alternately/—42.aB
|
R14/R24
Nesrlv.caual
level
eee
at
both
frequencies
Gee
ER
ROSES
TNEINGA
ket
Woe
wc
oe
ourTPUT:
BIAS, EQ: NORMAL 400 Hz & 10 kHz i
Tape:
MTT-501
alternately/—42.dB
|
R13/R23
Nearly
cate
level
LL
(6.15
mv)
at
both
frequencies
1
J