Sony TC-42 User manual

Power Requirements:
Track System:
Tape:
Tape Speed:
Recording Time:
(with C-120 tape cassette)
Frequency Response:
c Wow and Flutter:
Power Output:
Record Bias Frequency:
Apa NAENT TN ARE!
SPECIFICATIONS
DC 6 V with four penlight batteries,
house hold current with an ac adaptor
[AC-9 (USA and Canada),
AC-456C (E and AEP)], rechargeable
battery pack (BP-23) of 12 V de with
SONY car battery cord (DCC-126)
Two-track mono
SONY tape cassette or equivalent
17g ips (4.8 cm/s)
2.0 hrs total
50 ~ 10,000 Hz
0.38 % (RMS) weighted
500 mW maximum
Approx, 41 kHz
Input:
Output:
Speaker:
Semiconductors:
Dimensions:
Weight:
= CNY
SERVICE MANUAL
E Model
USA Mode!
Canada Mode!
AEP Model
CASSETTE-CORDER
MIC input
Impedance : low impedance
Maximum sensitivity : 0.2 mV (-72dB)
MONITOR output
Impedance
Output level
: 8Q or 10 kQ load
: 0.775 V (0 dB)
with 10 k{2 load
2 3%” (70mm)
Dynamic speaker
Voice coil impedance: 8 {2
1 FET, 13 transistors and 8 diodes
2° (W) x 7/6 IH) x 45/9 "(D)
(51 x 184x111 mm)
2 |b 3 0z (0.98 kg) with four
penlight batteries
&4

Section
Title
Page
Specifications.
2.0.2
2Ga“
See
Oo
Ge
ee
A
eee
BAS
l
1.
OUTLINE
l-l.
Servo
Control
Circuit
Operation
..........2.
0-2-0504
005
3
1-2.
Auto
Shut-off
Mechanism
Operation.
.............244-4
4
{-3,
‘Block
Diagram
0
2-4
.e.%
Ge
ae
oh
ee.
5
See
a
ee
5
[4°
External’
View:
+a.
le
id
ee
Sa
e
BG
Be
a
Ra
ee
dens
6
L=5..
Intéernak
Views
20
-Sek
R
Soe
eh
a
BP
Bee
ee
oe
Bae
Fe
6
2.
DISASSEMBLY
2-1.
Case
(A)-and:(B)
Removal...
2.
6.
we
ee
ee
8
2-2.
Case(C)
Removal
.......-0
20-2
eee
ee
ee
te
ee
9
2-3.
Complete
Circuit
Board
Removal...
2.2...
eee
eee
9
3-4.
‘Motof-Removal.;
2.
oa
eh
eco
s
Se
RRO
ae
Dee
9
9:5.
.Belt/Removalis
a
ce
6
eat
hee
ee
es
ESS
Ee
a
ele
9
2-6.
Midway
Pulley
Removal
...
2...
2.
ee
eee
ee
es
10
2-7.
Rewind
Idler
Slide
Removal
.............00.-
0.250004.
10
2-8.
Fast
Forward
Plate
Removal.
.....
Sng
os
ty
8
ifisa
gel
Bel
GET
10
2-9.
Take-up
Drum
Removal
..
2...
0 0
eee
es
10
3.
ADJUSTMENTS
3-1.
Mechanical
Adjustments
....
2...
0-2
ee
ee
es
11
3-2.
Electrical
Adjustments/Measurements
.........-.--+-+2-4-
13
4.
DIAGRAMS
4-1.
Schematic
Diagram.
2
220.6
2
eles
be
ek
ae
a
OR
ee
17
4-2,
Mounting
Diagrams...
...
2.2...
2
eee
ee
ee
19
453).
‘Level
Diagrams.
2
edie
ere
Re
a
KA
2
oe
See
eS
4
21
5.
EXPLODED
VIEWS
TABLE OF CONTENTS
5-1.
Exploded
View
(1)...
60
ec
es
23
5:9 Exploded’
View
(2):
23s)
0s
tye
pee
ee ee
a
se
ds
25
5-3.
Exploded
View
(3)
2.
0.
0
ce ee
es
Dil;
S24.
‘Packing
cox.
fos
d
se
sea
pele
io es
es
alee
ehh
8
BMA.
he
Bp
ae
a
28
ELECTRICAL
PARTS
LIST
..............
2.202.000.0058.
29

1-1.
SECTION 1
OUTLINE
SERVO CONTROL CIRCUIT OPERATION
Stage/Control
Frequency
generator (FG)
Discriminator
Q101
Function
This generator is coaxially cou-
pled with dc motor.
The frequency of FG varies in
direct proportion to the motor
rotation.
Active high-pass filter consisting
of Q101, C101, C102, R103,
R104 and R108 discriminates
the output of FG.
When the input frequency in-
creases, the output of the dis-
criminator increases, or vice versa.
filter A
output (V) Ay
to)
NZ
|
I
|
440 Hz re:
frequency {Hz}
Fig. 1-1. Filter characteristics
Stage/Control
Speed control
R101
filter
output (V)
Function
This control shifts the filter char-
acteristics.
Fig. 1-2.
Voltage stabilizer
D101
Rectifier
D102, D103
Direct coupled
dc amplifier
Qi02, Q103,
Q104
frequency (Hz)
Shift of filter characteristics
This diode stabilizes B+ voltage
for Q101 and Q102.
These diodes rectify the output
of the discriminator as a voltage
doubler.
This amplifier amplifies dc com-
ponent rectified by D102 and
D103 to control the motor cur-
rent. Since the output from FG
is not available when starting the
motor, no dc component is ap-
plied to QI02 base to turn Q102
off. Since Q103 base voltage is
high as B+ voltage, Q103 and
Q104 are conductive to start the
motor.
Qing, 103, 194
Be AME
+) B
Cig C192
—
R103
Fig. 1-3.
Outline of servo control circuit

1-2. AUTO SHUT-OFF MECHANISM OPERATION
TC-42 mechanism is designed so that the unit will shut itself off automatically at tape end in record or playback mode.
Gears in gear block ass’'y and FS
gear are not in mesh as long as tape
remains on the spindle in record or
playback mode.
tape tension pick-up
FWD/STOP knob
wy
ITNT
“ HATHA
At tape end in record or playback
mode. Tape tension pick-up detects
tape tension and gears in gear block
ass'y are moved to mesh with FS
Turning force of FS gear is trans-
mitted to gear B and jut of gear B
pushes function lever ass’y as shown
by the arrow.
function lever ass’y
After automatic shut-off operation
the unit is placed in stop mode.

1 4
RPH ==
SERVO CONTROL CIRCUIT
MOTOR
oo
\
\
\
Note:
Ref Switch Mode
OL | TRCOd ay Gack | play back
S2 | pause START
MONITOR
WVYSDVIG ND018 “EL

1-4. EXTERNAL VIEW
X-3538-510-0
button ass’y, REC
X-3538-509-0
button ass’y, REW
X-3§38-508-0
button ass’y, FF/CUE
3-538-524-00
‘2g knob, FWO/STOP
—— 1-520- 198-00
meter, REC/BATT
3-528-004-00 pied bade
button, EJECT
8-814-190-10
electret condenser microphone
3-538-523-00
knob, pause
1-507-169-13
jack, mini; MONITOR
1-507-127-00
jack, external power
1-507-195-13
jack, REMOTE
1-507-169-1232
jack, mini; MIC
1-5. INTERNAL VIEW
CHASSIS — Top View —
8-829-336-00
head, record/play back
(PP 134-36}
X-3515-005-0
pinch roller ass’y
8-825-566-00
head, erase (EBF 5-028)
X-3515-015-0 3-528-084-00
spindle ass’y, take-up reel spindle, supply reel
-~6—

CHASSIS — Rear View—
1-§14-264-00
switch, slide: cue (S4)
X-3515-008-0
flywheel {A) ass‘y
X-3515-016-0
Hl is je
3-480-
135-00
pulley
ass’y,
midway
Bales
3-480-136-00
belt (8)
A-3070-006-A
complete
circuit
board,
amp/osce
1-514-346-00
X-3480-006-0
switch,
leaf:
power
(S3)
flywheel (8) ass’y

2-1. CASE (A) AND (B}) REMOVAL
Remove the four
screws (B 2 x 5).
case (A)
Remove the
battery case.
Pull off the FWD ©) Remove the upper
button. panel.
GB) Remove the screw
(P 2 x 8).
Remove the two
screws (B 2x 10).
upper panel
case (B)
Remove the two
screws (B 3 x 8).

2-2. CASE (C) REMOVAL
1) Remove the two screws (P 2 x 4).
case (C}
2-3. COMPLETE CIRCUIT BOARD REMOVAL
Servo
Control
Circuit
Board
|
Amp/Osc
Circuit
Board
@) Remove the screw (P 1.7 x 2.5).
Note: Do not touch the circuit
board to terminal strip.
Remove the three @) Remove the screw
screws (P 2 x 5). (P2x 5).
2-4.
MOTOR
REMOVAL
2-5.
BELT
REMOVAL
@) Unhook the bei/t from
motor pulley. peg |
@) Remove the screw |
(P2x 3}.
thrust retainer
Q) Remove the screw
(P2x 3).
Remove the circuit
; board support {A}.
Push out
the motor.

2-6. MIDWAY PULLEY REMOVAL 2-8. FAST FORWARD PLATE REMOVAL
: : ) Remove the two
Remove the retaining @) Unhook the tension | retaining rings (C-2).
ring (C-2). spring. @) Remove the
rewind lever.
@) Unhook the
tension spring.
&
' —— ) Remove the screw
(P 1.7 x 2.5).
midway
pulley ass’y
Remove the slide switch
operating lever.
i
Remove the retaining
rings (C-2).
Remove the ae
forward lever.
Remove the fast
forward plate ass’y.
Unhook the tension
spring.
2-7. REWIND IDLER SLIDE REMOVAL
Remove the torsion Remove the retaining ‘
spring.
a
ring
(C-2).
2-9.
TAKE-UP
DRUM
REMOVAL
Remove
the
retaining
Q)
Remove
the
retaining
3)
Unhook
the
ring
(C-2).
ring
(C-2).
tension
spring.
(4) Remove the flywheel
. (B) ass’y.
Remove the rewind
idler slide ass‘y along
with rewind idler
lever ass’y.
(4) Remove the boss.
6) Remove the screw
(P 1.7 x 2.5).
©) Remove the
take-up drum.
GQ) Set the function
button to FWO
—~10—