Sony TC-640 User manual

Power Requirements:
Track System:
Reel Size:
Tape Speed:
Recording Time:
(with 1,800 ft. tape)
Frequency Response:
we
Signal-to-Noise Ratio:
SPECIFICATIONS
AC 100 V,110V,117V,
120 V, 125 V, 220 V, 240 V
50/60 Hz, 80 W (for General Export)
AC 117 V, 60 Hz, 80 W (for USA)
Four-track stereo and mono
7” (18 cm) maximum Inputs:
7% ips and 3% ips
(19 cm/s and 9.5 cm/s)
4-track 4-track
Tape speed stereo. mono
7% ips 1.5hrs 3hrs
(19 cm/s)
3%
ips
3hrs
6
hrs
Outputs:
(9.5
cm/s)
5
30 ~ 20,000 Hz at 7% ips
(19 cm/s)
30 ~ 15,000 Hz at 3% ips
(9.5 cm/s}
{with standard tape)
20 ~ 25,000 Hz at 7% ips
(19 cm/s)
30 ~ 18,000 Hz at 3% ips
(9.5 ¢m/s)
(with SONY SLH tape)
Weight:
52 dB (with standard tape)
55 dB (with SONY SLH tape)
Flutter and Wow:
Recording Bias Frequency:
Semiconductors:
Dimensions:
8 [ISO)
Set using 1SO screws
0.07 % (WRMS) at 7% ips
(19 cm/s)
0.11 % (WRMS) at 3% ips
(9.5 cm/s)
120 kHz
Two MICROPHONE inputs
Impedance; 600
Maximum sensitivity: 0.19 mV
(—72 dB)
Two LINE INPUTs
Impedance; 100 k{2
Maximum sensitivity; 60 mV
(—22 dB)
Two LINE OUTPUTs
Impedance; 100kQ2 ,
Output level; 0.775 V (0 dB)
HEADPHONE output
Impedance; 8
Output level; 38 mV (—26 dB)
with 8 92 load
22-transistors and 8-diodes
1417/32(w)
x
159/16(H)
x
919/32"
(D)
(369
x
395
x
243.5
mm)
33 Ib 2 0z (15 kg)
SON
Ye
SERVICE
MANUAL

Section Title
Specifications
1. GENERAL DESCRIPTION
1-1.
1-2.
Block Diagram
Major Parts Locations
2. DISASSEMBLY.............
3. FREQUENCY ADAPTATION
4. MAINTENANCE
4-1. Lubrication ..........
4-2. Cleaning eerie bea Bees
4-3. Demagnetizing.........
5. ADJUSTMENT PROCEDURES
5-1,
5-2.
Mechanical Adjustments. ...
Electrical Adjustments. ...
6. DIAGRAMS
6-1. Schematic Diagram .....
6-2. Mounting Diagram
6-2-1. REC BIAS Circuit Board . .
6-2-2. PB AMP Circuit Board... .
6-2-3. System Control
Circuit Board
TABLE OF CONTENTS
Page Section Title
: ] 6-2-4. REC MODE Circuit Board
6-2-5. SOS & ECHO Circuit Board
6-2-6. Resistor Terminal ......
3 6-3. Level Diagram. .......
4~5
7. SEMICONDUCTOR ELECTRODES...
. 6
8. ELECTRICAL PARTS LIST ....
: 6
9. EXPLODED VIEWS
9-1. Cabinet - topview-— ....
7 9-2. Amp Chassis
: 7 —topview(l)-.....
‘ 7 9-3. Head Deck —top view(1) ..
; 9-4. Head Deck —top view(2) ....
9-5. Printed Circuit Board
—topview-—.......
8~11 9-6. Chassis —topview~.....
12~24 9-7. Chassis —bottom view ~—. . .
9-8. Jack Panel .........
9-9, Packing 20 5 Se ee
5~28
é 10. HARDWARES ............
29~32 Hardware Nomenclature .......
33~36
37~38

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1-2, MAJOR PARTS LOCATIONS
Cabinet — Front View —
Y¥-20410-12-6S
counter, tape index
_ X-3 1440-08
3-144-042-10
cabinet
ass‘y,
wood
panel,
reel
3-140-864-01
3-140-864-01
reel
table
reel
table
1-514-692
switch, lever; MONITOR (S302)
3-144-058
3-144-050-20
cover, head knob, lever switch; REC
X-31408-07
x-
-3
1408-04
;
roller
ass’y,
guide
:
pinch
roller
ass’y
144-128
3-144-050-30
-
oe
tton
knob,
lever
switch;
rewind
1-514-769
(S305,
S306)
;
Spa
e
ee
er
3-144-050-40
knob, lever switch; stop
3-144-050-10
knob, lever switch; forward
3-144-050-30
knob, lever switch; fast forward
3-144-079
cover, pushbutton 8B
1-514-789
switch, slide; TAPE SPEED (S301)
X-3 1440-09
knob B ass‘y, PB VOL
X-3 1440-09
knob B ass‘'y, LINE VOL
switch, lever; REC MODE
1-507-28 1 (J301, J302)
jack, MICROPHONE
1-507-282 (J303)
jack, binaural: HEADPHONE
X-3 1440-11
knob C ass'y, VOL (ECHO/SOS)
1-514-324 (S303)
switch, slide; SOS & ECHO
X-31440-09
knob B ass'y, MIC VOL
1-513-347
switch, slide; TAPE SELECT (S307)
Cabinet — Back View —
3-456-002
grille, ventilation
1-509-341 (CNJ402)
socket, AC OUTLET
171-509-064
1-507-142
(J304,
305)
socket,
voltage
jack,
phono:
LINE
INPUT
selector
(J403)
LINE INPUT,
(for General Export}
171-509-029 (J308)
owen
SUPPLY
:
\
"
‘
connector,
REC/PB
171-509-062 (CNJ401) seoune 4 ! ~ : (for General Export}
socket, POWER SUPPLY ® 5 \ i :
f 1-507-142 (J306, 307}
jack, phono; LINE OUTPUT
X-380 12-04
terminal ass‘y, GROUND
171-532-100
fuse, 2A

Chassis — Front View —
1-514-324-11 (S407)
switch, slide; 50/60 Hz
(for General Export)
X-3 1428-30
brake (R) ass’y
3-144-037
be/t, counter
X-3 1428-29
brake
(L}
ass‘y
3-144-033
pulley, motor
1-454-080 (PM401)
solenoid, pinch roller
3-140-520
belt, capstan
1-454-079 (PM402}
solenoid, brake
1-524-077
meter, VU {(ME301, 302)
Chassis — Back View —
1-117-083 (C402)
capacitor, metalized paper 1-441-680 (T401)
transformer, power
(for USA)
1-441-694 (T401)
transformer, power
(for General Export}
1-54 1-033-21 (M402)
motor, reel (CM-71)}
8-83 1-634-13 (M401)
motor, capstan (HC-634D5)
1-117-083 (C403)
capacitor, metalized paper
1-54 1-033-21 (M403)
motor, reel (CM-71)

SE
CTION 2
DISASSEMBLY
A@RK 4x25
O@RK 4x 15
Fig. 2-1.
Cabinet Removal
Panel
SECTION 3
FREQUENCY ADAPTATION
Remove the front
four screws.
panel by loosening the
Set the frequency selector for the line fre-
quency of your local area.
Remove the motor pulley by the two set screws
and reinsert the motor pulley upside down,
then tighten the screws again.
cep
Remove the cabinet by removing the seven screws
marked with A in Fig. 2-1.
Removal
Remove the panel by removing the four screws
@RK 4 x 15) marked with o in Fig. 2-1.
4. Slightly loosen the four screws which tighten
the capstan motor to the chassis. Then, slide the
motor as illustrated and tighten the screws
again.
5. Replace the rubber belt on the motor pulley so
that the belt is threaded horizontally. Try to
turn the motor pulley several times to see
whether the belt is threaded securely.
6. Replace the front panel.
6OHz 50Hz
a
@( je
cP
ee
Fig. 3-1.
Frequency adaptation
es

SECTION 4
MAINTENANCE
4-1. LUBRICATION
Use
light
machine
oil
and
lubricate
the
pinch
roller
shaft
and
capstan
drive
motor
lubricating
hole.
It
will
cause
slippage
of
the
mechanism.
If
the
oil
spills
on
the
pinch
roller
or
the
rubber
belt,
wipe
it
off
immediately
with
denatured
alcohol.
To
lubricate
them,
proceed
as
follows:
Avoid excessive lubrication.
(1)
Remove
the
head
cover
and
the
screw
securing
pinch
roller
and
then
lubricate
the
pinch
roller
shaft
with
one
drop
of
light
machine
oil.
(2)
Remove
the
reel
panel
and
lubricate
the
motor
lubricating
hole
with
several
drops
of
light
machine
oil.
Note: Use the oil which is comparatively
viscous at the pinch roller shaft.
4-2. CLEANING
Dusts and dirts which were brought by tape
may stick to the core of the record, playback or
erase head, and they may deteriorate the perform-
ance of the record and the playback heads. So wipe
off the surface of the heads, with a clean and soft
cloth dampened with denatured alcohol. To ensure
proper operation, the heads should be cleaned at
least once during each ten hours of actual operation.
CAUTION
Do not use any other ‘solvent on the head as
some will damage the material which binds
the head laminations together. Also do not
use any metallic device which will scratch the
head.
At the same time, clean capstan, rubber belt,
pinch roller, tape guide, flutter filter roller and
tension arm.
4-3. DEMAGNETIZING
The record and playback heads may occasionally
acquire a degree of permanent magnetization, which
will result in an increase of noise level, distortion of
any recorded signal, and a gradual erasure of high
frequency on any recorded tape which passed over
them. These heads may be easily demagnetized
with a SONY head demagnetizer HE-2 (optional
accessory) or equivalent.
To demagnetize the heads, proceed as follows:
Steps:
(1) Remove the head cover.
(2) Make sure that power switch on the TC-640
is in the OFF position.
(3) Connect the demagnetizer to ac power source.
(4) Bring the tips of the demagnetizer in close
proximity to, but not in contact with, the
heads so that the tips straddle the gap in the
center of the head, run the tips up and down
the heads several times, and then slowly with-
draw the demagnetizer.
CAUTION
Do not bring magnet close to heads.

5-1.
5-1-1.
SECTION 5
ADJUSTMENT PROCEDURES
MECHANICAL ADJUSTMENTS
171-117-083 (C402)
capacitor, metalized paper
171-117-083 (C403)
capacitor, metalized paper
1-541-033-21 (M403)
motor, reel (CM-71) -
1-117-040 (C401)
capacitor, metalized paper
1-441-680 (T401)
transformer, power (for USA)
1-441-694 (T4017)
transformer, power (for General Export)
1-541-033-21 (M402)
motor, reel (CM-71)
8-83 1-634-13 (M401)
motor, capstan (HC-634D5}
Adjusting parts locations
Automatic Shut-off Switch Adjustment
Remove the head deck by taking off the two
screws, and put it upside down on a soft cloth.
Make sure that the shut-off lever does not touch
the head deck when pushing it by the hand.
See Fig. 5-1-1.
If necessary, adjust the position of the actuator
bracket by loosening the screws A.
Place the head . deck
See Fig. 5-1-1.
in a normal position.
Push the shut-off lever slowly by the hand, and
check to see that the microswitch turns on when
the lever comes the one-third position of the
slot as shown in Fig. 5-1-2.
If necessary, adjust the position of the micro-
switch by loosening the screws (B) and (C).
Release the shut-off lever, and make sure that
the microswitch turns off when the actuator
comes at one-fourth position of the slot (See
Fig. 5-1-2).
Make
sure
that
the
shut-off
lever
reaches
the
top
of
the
slot
when
pushing
the
lever
by
the
hand.
9. If it is not, readjust the position of the actuator
bracket.
actuator bracket
shut-off lever
Fig. 5-1-1. Automatic shut-off Switch adjustment (1)
shut-off lever ri *]
one _ U
% ia
Fig. 5-1-2, Automatic shut-off switch adjustment (2)

5-1-2.
Pinch
Roller
Pressure
Adjustment
1.
Place
the
unit
in
the
play
mode
to
energize
the
pinch
roller
solenoid,
and
turn
on
the
automatic
shut-off
switch.
Note: Hold the shut-off lever so that the shut-off
switch is activated (a rubber band or a piece
of masking tape will hold the shut-off lever
as though tape were threaded on the unit.)
2.
Adjust
the
adjusting
nut
(A)
for
1
mm
(3/64”
)
clearance
between
the
link
shaft
and
the
adjust-
ing
nut
(A).
See
Fig.
5-1-3.
:
3.
Attach
the
spring
scale
(5
kg)
to
the
pinch
roller
shaft
with
a
piece
of
string.
See
Fig.
5-1-4.
Pull
the
scale
horizontally
in
the
direction
shown
by
the
arrow.
The
capstan
shaft,
pinch
rolier
and
the
spring
scale
should
be
in
a
line.
Check
the
reading
just
when
the
pinch
roller
separates
from
the
capstan.
4, Adjust the adjusting nut (B) for 2.2 + 0.2 kg.
(4.4 to 5.3 1b)
5. Repeat steps 2 to 4 several times.
6. After adjustment, lock the adjusting nut (B) by
the lock nut (B).
7. Adjust the adjusting nut (A) for the clearance
of 0.1 to 0.2 mm between the lock nut (A) and
the link shaft.
8, Lock the adjusting nut (A) by the lock nut (A).
9, Check for the correct value again.
link shaft areal
lock nut (A)
adjusting
nut
(B)
adjusting
nut
(A)
Fig. 5-1-3. Pinch roller pressure adjustment (1)
Pull the spring scale aA
in the direction shown
by the arrow.
capstan
TS
pinch roller
Fig. 5-1-4. Pinch roller pressure adjustment (2)
5-1-3. Microswitch Position Adjustment
1. Check to see that the microswitch (for pinch
roller solenoid) is turned on when the pinch
roller touches the capstan. See Fig. 5-1-5.
2. If it is not, adjust the position of the micro-
switch by loosening the screws A.
to be contact
capstan
pinch roller
Fig. 5-1-5. Microswitch position adjustment
5-1-4. Reel Motor Torque Adjustment
Take-up Motor Torque Adjustment
1. Place the reel with string wound several turns
clockwise on the hub (44 mm dia) onto the
take-up reel table. Tie the string to the spring
scale.
2. Hold the shut-off lever so that the shut-off
switch is activated (a rubber band or a piece of
masking tape will hold the shut-off lever as
though tape were threaded on the unit).
3. Place the unit in the play mode. Pull the spring
scale and then allow to take up the string on the
reel while approaching the scale to the reel at
the same speed of tape running. Adjust RV401
for 330 to 350 g-cm (4.58 to 4.86 oz. inch) on
the spring scale. See Fig. 5-1-6.
Note: Read the scale while moving it.

5-1-5,
Back Tension Torque Adjustment
Place the empty hub with string wound several
turns counterclockwise on the hub (44 mm dia)
onto the supply reel table. Tie the string to
the spring scale.
Hold the shut-off lever so that the shut-off
switch is activated (a rubber band or a piece of
masking tape will hold the shut-off lever as
though tape were threaded on the unit.)
Place the unit in the play mode. Pull the spring
scale at the same speed of tape running. Adjust
RV402 for 240 to 260 g-cm (3.32 to 3.60 oz.
inch) on the spring scale. See Fig. 5-1-6.
Note: Read the scale while pulling it.
Fig. 5-1-6. Reel motor torque adjustment
Brake Torque Adjustment
This adjustment should be performed for both
supply and take-up sides.
Note: The instructions in [ ) are applied to the
’ supply brake torque adjustment.
Place the unit in the STOP mode.
Bend the portion A _ of the brake lever
with a pair of pliers so that the clearance
between the brake lever and the limiter is
approx. 2 mm (5/64").
Place an empty reel with string wound several
turns counterclockwise [clockwise] on the hub
onto the reel table.
Tie the spring to a spring scale.
—~10—
4. Pull the spring scale horizontally at a constant
speed, making sure that the string does not
touch either flange of the reel. The reel table
will rotate counterclockwise [ clockwise }.
Take a reading only when the reel table is in
steady motion.
5. Make sure that the brake torque is 350 to 450
g.cm (4.86 to 6.25 oz. inch).
6. Place an empty reel with string wound several
turns clockwise [counterclockwise] on the hub
onto the reel table.
Tie the spring to a spring scale.
ti Pull the scale horizontally at constant speed,
making sure that -the string does not touch
either flange of the reel. The reel table will
rotate clockwise { counterclockwise ].
Take a reading only when the reel table is in
steady motion.
8. Make sure that the brake torque is 1,000 to
1,300 g-cm (13.9 to 18.1 oz. inch).
9. If it is not, change the hooking position of the
spring for the specified brake torque.
10. Check to see that the center pole of the
solenoid should be pulled out from the
solenoid by approx. 3 mm(1/8") in STOP mode
as shown in Fig. 5-1-9.
If it is not, adjust the position of the brake arm
bracket A marked with x.
11. Make sure that the capstan belt does not rub
against the portion marked with a of the brake
lever in the play mode.
Specification:
Brake Torque of Supply Reel
in clockwise turning .. 350 - 450 g-cm
(4.86 - 6.25 oz. inch)
in counterclockwise turning
. 1,000 - 1,300 g-cm
(13.9 - 18.1 oz. inch)
Brake Torque of Take-up Reel
1,000 - 1,300 g-cm
(13.9 - 18.1 oz. inch)
in clockwise turning ..
in counterclockwise turning
.. 350-450 g-cm
(4.86 - 6.25 oz. inch)