Sony TC-765 User manual

GENERAL
Power Requirements:
Power Consumption:
AC Outlet:
Dimensions:
Weight:
Track:
Tape Speed:
SPECIFICATIONS
Fast Forward and
120V ac, GOHz (US, Canadian model} Rewind Time:
110V, 120V, 220V, 240V ac, 50/60 Hz
(UK, AEP, PX model)
110W (US, Canadian modei)
Q9OW (UK, AEP model)
80W (PX model)
Recording Time:
300W, unswitched (US, Canadian model) Heads:
Approx. 445 (w) x 525 (h) x 235 (d) mm
17 1/2 (w) x 205/ (h) x 91/4 (d) inches Motors:
including projecting parts and controls
26.5 kg, 58 !b 7 oz (US, Canadian model) Reel:
27 kg, 58 1b 8 oz (UK, AEP, PX model)
4-track 2-channel stereo recording and playback
19 cm/s (7% ips)
9.5cm/s (3% ips)
Approx. 150 seconds with 740 m (2,400 ft) tape
With 1,100 m (3,600 ft), 27cm reel
Stereo recording
180 minutes at 19cm/s
Mono recording
720 minutes at 9.5 cm/s
Record head 1, Playback head 1
Erase head 1
AC servo-controiled capstan motor 1
Induction reel motor 2
Up to 27cm (10%-inch)
— Continued on page 2 —
SERVICE MANUAL

TC-765
Frequency Response: With Sony Ferri-Chrome tape Equalization:
30—25,000 Hz + 3dB at 19 cm/s
30—18,000 Hz + 3dB at 9.5cm/s
With
SLH
tape
Inputs:
30—25,000 Hz + 3dB at 19 cm/s
30—18,000 Hz + 3dB at 9.5cm/s
With regular tape
30—18,000 Hz + 3dB at 19 cm/s
30—15,000 Hz + 3dB at 9.5cm/s
Wow and Flutter: NAB
0.04% WRMS at 19 cm/s
0.08%
WRMS
at
9.5
cm/s
Outputs:
DIN
40.07% at 19cm/s
+0.15% at 9.5cm/s
S/N Ratio: 61dB (NAB) with Sony Ferri-Chrome
Tape
61d8 (DIN 1975 rev.) with Sony
Ferri-Chrome Tape
56 dB (DIN, old)
Total Harmonic
Distortion: 0.7% Other Jack:
Bias Frequency: 160 kHz
MODEL IDENTIFICATION
Specification label
UK, AEP model US model
TAPECORDER TC-765
110.120.220.240V ~~ 50/60Hz 90W
MADE IN JAPAN
Canadian model PX model
TAPECORDER TC-765
AC 120V 60Hz HOW
MADE IN JAPAN
3,180uS + 50uS (19 cm/s)
3,180uS + 90uS (9.5 cm/s)
MIC (two phone jacks)
Sensitivity: 0.2mV (-72dB)
Impedance: for low-impedance microphone
LINE IN (two phono jacks)
Sensitivity: 0.06V (-22 dB)
Impedance: 100 kQ
REC/PB (connector) (UK, AEP, PX model)
Input impedance: less than 10k
LINE OUT (two phono jacks)
Normal level: 0.435V (-5 dB) with PB LEVEL
contro! set to center detent position
0.775V (OdB) with PB LEVEL
control set to ‘10’
Load impedance: 100k
Suitable load impedance: more than 10kQ
HEADPHONES (binaural jack)
Load impedance: for low-impedance headphones
REC/PB (connector) (UK, AEP, PX model)
Output impedance: Jess than 10kQ
11-pin remote control connector
0dB=0.775V
SON'Y.
TAPECORDER TC-765
AC
I20V 60 Hz HOW
MADE IN JAPAN
TAPECORDER TC-765
AC I20V 80W 50/60Hz

TC-765
SECTION 1
OUTLINE
1-1. BLOCK DIAGRAM — System Control Section —
o-—
(REC EQ SWITCHING)
eo
(REC AMP SWITCHING)
EMITTER
FOLLOWER
y 0732
SCHMIDT
SWITCHING SWITCHING FLIP FLOP TRIGGER ee (Fs) RV9O!
0732
073!
9730
0729,
728
aaa
0725,
724
Nx
“N
~~
TC-765
od $602
S602"! [TAPE SPEED
19cm —> 9.5em
S60l-|__—_ S60I-2
B+
STABILIZING
SUPPLY
Q704,705
0708~713
Bt
switcHine| _ | BoGENO!D
SUPPLY
a! 8707,708
OPERATES
IN FOR-
Sour SWITCHING
714, 715 ar7i6
SOLENOID
DRIVER
Q712, 713
SOLENOID
ORIVER
Q710 ,7il
| switcuine | D719
he 9709 re
|
$605 g
SHUT OFF
pay (SUPPLY)
(PB MUTING) ° LAMP DRIVER LAMP DRIVER 0760 _| SWITCHING
0718 9720 722
EMITTER
FOLLOWER
Q733
i
24V
|
me
he
REEL
SIZE
|
oh
V2?
|
TAPE
SPEED
ADJ
b | {Rvg0! 93cm
RV902 9.5¢em
|
all
!
RV702 ‘|
INVERSE 0744~747
TENSION
TORQUE
EMITTER
FOLLOWER
: SUPPLY REEL
MOTOR DRIVER
7 a
(FUNCTION BUTTON]
ea ms > Pl
ly <Ge<ee ee oe case. fl B+
STABILIZING
POWER SUPPLY
Q70t~ 703
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24V ADJ
a «< 8 ?-
(C701 :
SYSTEM aes ,)
CONTROL \()~(@): 0U
0
ON OFF
(BIAS
OSC)
5603
(7)
b
®
(*)
D766
[TIMER]
7
Sees
Pera
(REC
MUTING)
aes
(AEP,
UK,PX
PORE
mamta
B+
werd
ae
D767
wooe)
_t
I
iS
SUPPLIED
WHEN
B+
‘
TAPE
REC
MODE
SWITCH
e@
(S103,S303)IS
ON.
L,
(LINE OUT
MUTING)
0765
SWITCHING
©
@
oT
i
748
©)
CO?’
cneoi
i
REMOTE
OFF
=
[ozes
EMITTER
ETIPEELOP:
ASTABLE
0764
O
O
$607
SWITCHING
FOLLOWER
sniteeine
Sa
MULTIVIBRATOR
O
C>/
IcontRo.
REC
a740
74!
a74a2
”
0746,
747
O
O O
MONITOR
MUTE
pa ey
D762
SONY-00527 / DRUCK 1
$602-2
Sem—> 9.5¢m
7 i/2
3 3/4
CAPSTAN
MOTOR
DRIVER
Q90I~903
D906~ 309
00009090000
PT60I

SONY-00527 / DRUCK 2

1-2. BLOCK DIAGRAM — Amplifier Section —
MIC_ATT (dB)
0
JO! Vo
rh 15
Ha pao 4
Mic AMP
Q!0!, 102
? LINE AMP
RVIO! Q103 ~ 105
| TC-765 TC-765 |
C135
REC BIAS A DJ
osc
. py] S103-4
nee
|
HRIOI
UNIT
ae
eal
7
>
PB
Qt
=
RFI40-2902
;
LI06
[REC]
REC BIAS TRAP. '
[mic]
MUTING REC -
aioe [REC MODE] !
US,CANADIAN
MODEL
REC
giog-3
HEE
MOD
$!03-!
— , =e LEVEL Lioe REC £0 ae F ees - [REC MODE]
LINE 09 = & xX EFI8-2902A2 } f$__ Bt
H si02~| Sey p avers 1 ERASE REC
aa 5 P NORMAL—> SPECIAL—>Fe ~Cr| yar H L107
f AEP, UK PX MODEL I ! | J O 9 | DUMMY VOLTAGE
RCH R-CH ? CONTROL
I 1 switcHinc] [switchinc] [switcHinc | |switchine | [SwiTcHING
L (EQ) (EQ) (EQ) (EQ) (EQ) $501
LINE
AMP
“fe
ve
Qulo
Qill
ail
Qits
aul4
dees
g
18+)
! Q126, 127 Si06 Rec/ Pe! LOW*-MED-"HIGH 9 ¥ 0 © ¥ ©
INPUT SELECT |
I
| iH) CN5O) |
| REC/PB l R-CH
SSS
SS
Se
ae
aS
Se
Se
s
TIO!
t SWITCHING | /2506_ON WHEN TAPE SPEED
HPIOI
RVIO4
p
HEADPHONE
AMP
ef}
950
0506
SWITCH
(S602)
TURNS
me se ae PB EQ AMP |PBLEVEL ADJ PB LINE AMP | sts l] iaeapeHONES 9.5m(3 3/4) MODE
QuS 17 ao Qi2t~ 123 3104 D
D103
MONITOR RVIO6 MEIO! Fy FROM
am) SOURCE METER ADJ STABILIZING | _POWER SUPPLY
GED
RVIOS
{
Osoie
Ge
OF
SYSTEM
CONTROL
f
:
[PB
LEVEL]
TAPE
CD
6
J303
z ee eee) ee > {LINE our
RY502 1@ H
MUTING 4 RY501 | Ca
gi20 : PRy503 |
|
SWITCHING SWITCHING ! I | -
9508 0507
Q507 ON: I !
Q508 ON WHEN TAPE SPEED WHEN REC MONITOR MUTE SWITCH(S607) TURNS OFF, |
SWITCH
(S602)
TURNS
OR
WHEN
REC
MONITOR
MUTE
SWITCH(S607)
TURNS
|
19cm (7 1/2) MODE ON AND MONITOR SWITCH(SI04) TURNS TAPE DIRECTION }
IN PLAYBACK MODE i Fr
!
|
———_-—-—)
Sees Ce [pS See ea ee ee ee Se 5
SWITCHING AEP, UK PX MODEL
|
9509
G
|
| |
| (Bean ON: WHEN ) |
| (MONITOR SWITCH(SI04) TURNS TAPE DIRECTION IN PLAYBACK: MODE
|
(eo ee a ed J
SONY-00527 / DRUCK 3

1-3.
NOTE ON REPAIRING
NOTE ON REPAIRING
1.
This set does not change playback level when
TAPE SELECT switches are changed.
The LINE OUT signal is cut when REC MONI-
TOR MUTE switch (S607) on the rear panel is
turned ON except when MONITOR switch is
in TAPE position in playback mode.
If TIMER switch is previously set to ON
position, it may happen to erase test tapes
because the set becomes automatically in the
auto playback (awakening) or auto record mode
determined by REC MODE switch position
when POWER switch is turned ON.
PB LEVEL controls on the front panel control
LINE OUT and HEADPHONES levels, and also
VU meters indicate the amount of PB LEVEL
controlling. When PB LEVEL is in the center-
click positions, LINE OUT levels are standard
0.44V (-5dB) and VU meters indicate ‘‘0”’.
When PB LEVEL controls are in their full-
clockwise stops, LINE OUT levels are 0.775V
(0 dB).
. Three kinds of hexagonal-socket screwdrivers
are needed for the following adjustment/
removal.
Screwdriver Adjustment/removal
Tension-arm pin
O + 1.27 Intermediate pin
ane Switch knob
Switch lever
Head azimuth
OT Ls FG-holding boss
ee Control knob
Motor pulley
SONY-00527 / DRUCK 4
| TC-765 1TC-765 |
Tape BIAS/EQ recommendations
The following list shows the recommended
settings, which have been determined through
critical listening tests and electrical character-
istic measurements on commercially available
tapes. The setting can be changed according to
the personal preference. For Sony tapes, be
sure to use the recommended settings to obtain
the optimum tape characteristics.
NORMAL SPECIAL
BASF LH, LHS SCOTCH #211,
SONY PR AGFA PE, PEM #212, #213
_|MEMOREX AMPEX 406, 407
SONY SLH SONY DUAD
SCOTCH CLASSIC |SCOTCH #206,
TDK AUDUA #207
MAXELL UD
SCOTCH #250
SCOTCH #218
SECTION 2
DISASSEMBLY
(to Mechanical Adjustment)
(to VU Meter and Variable Resistor Replacement)
(to Fuse Replacement)
(to Audio Amp Board Check)
(to Tape Speed and Forward Torque Adjustments)
(to B+ and Supply Reel Back Tension Adjustments)
(to System Control Board Checking)
Reel Panel Removal:
Amp Panel Removal:
Perforated Panel (top) Removal:
Perforated Panel (bottom) Removal:
Side Board (right) Removal:
Side Board (left) Removal:
Rear Board Removal:
>
0,90
8,0
0,9
0,0
®,®
®,®
©, ®
® ©
CS)
RK3x8
washer 12)
reel panel washer RK 3x8
reel panel
washer 0
reel sher
washer eel panel washe
reel panel washer 5)
RK3x8 f
°|
amp panel
perforated panel (top)
@ 84x10
ral
@ PS4xi0'
perforated panel
(bottom)
foot ass’y
rear board

SONY-00527 / DRUCK 5
TENSION ARM BASE REMOVAL
Microswitch Installation
Turn the tension lever and adjust
the position of the microswitch for
the specified clearance when
switches.
microswitch (S605)
tension lever
HEAD COVER REMOVAL
RK3x8
@ washer.
OPS3x6
@ tension arm
@ pinch roller -
® 83x8
@® lever caps
(Use hexagonal screwdriver.
OL 1.27 mm)
Note: When reattaching the pinch rollers,
be sure to reattach the one with
“1” mark at the right side.
@ tension roller cap
(Hold the guide roller ass’y
and remove the cap by
turning counterclockwise.)
E25
plastic washer (3mm dia.)
(4) tension roller ass‘y
@O kK2x5
@ spacer
@ tension arm
© B3x5
@Q tension arm base
@ vee! panel
RK3x8
washer }@
washer
© pinch roller screw
!
@ pinch roller cap
() plastic washer (4mm dia.}
!
pinch roller with “1” mark
'p tension arm
{E} head cover
| TC-765 TC-765 |
REEL TABLE REMOVAL
/
0 P3x8 —_¢ 49 table
MOTOR PULLEY INSTALLATION
Use a hexagonal screwdriver.
©) 1.5mm
motor pulley
brake solenoid holder
chassis
ELECTROSTATIC DISCHARGE BRUSH
INSTALLATION
0.5-0.8mm
drive belt
~ electrostatic disch arge
brush

SECTION 3
MECHANICAL ADJUSTMENT
3-1. MECHANICAL ADJUSTMENTS
Tape Path Adjustment
1. In playback mode, travel a blank tape SLH-S1,
and adjust the positions of the tension-arm
guide and intermediate pin.
adjustment screws (hexagonal socket)
tension arm
guide
guide roller intermediate pin
Tape should travel
in the center of
this width.
After the adjustment, tighten the adjustment
screws.
Travel a blank tape SLH7-740 and adjust the
position of the tape guides to eliminate tape
curls.
2.
0.025mm
tape guide
tape guide
Travel a blank tape SLH-S1 and adjust the
height of each head for the specified clearances.
To adjust the erase head height, select appro-
priate spacer.
To adjust the record and playback heads, turn
the height/zenith adjustment screws in the same
angle and direction.
height/zenith adjustment screws
After the adjustment, apply a suitable locking
compound to the adjusted screws.
SONY-00527 / DRUCK 6
Reel Table Height Adjustment
| TC-765 TC-765 |
— playback and rewind modes —
1.
Loosen the adjustment screws and adjust the
height of the reel tables for the specified height.
If the tape touches the reel in playback, fast
forward and rewind modes, recheck the tension
arms, standard reels and the tape.
Pinch Roller Lever Position Adjustment
Remove the head cover.
Reattach both the pinch rollers.
Place the set in the playback mode. Check that
the solenoid is in on condition (energized).
Loosen the adjustment screw and push the
slide adjustment plate in the arrowed direction
for the specified clearance between the pinch
roller levers A and B, and tighten the adjust-
ment screw.
After the adjustment, apply a suitable locking
compound to the adjustment screw.
Pinch roller lever B
pinch roller {right}
sliding adjustment plate
adjustment screw
Note: Adjustment screw positions for the 2T
PB and 4T PB heads are the same as the
2T REC head.
Azimuth adjustment screws are so con-
structed to react each other. Take care
in adjusting azimuth adjustment screw.
Tape should travel in the center of this width.
7" standard tape reels
height/zenith adjustment screws
5+0.5mm
(123/39)
reel tables
SC4x6
chassis
adjustment screws
(hexagonal socket}
angle adjustment
screws azimuth adjustment screws
Brake Adjustment (1) brake band shoe
adjustment screw brake band
Adjust both the supply- and take-up-side brakes.
brake solenoid brake band guide
In stop mode, 0.5—0.7mm clearance should
exist between the brake-band guide and brake
band.
In playback mode (the brake solenoid should
be in ON condition), loosen the adjustment
screw and adjust the position of the solenoid
link in the arrowed direction so that the brake
band and brake-band guide uniformely touch.
solenoid link @ In playback mode, the
brake band should
uniformely touch the
brake band guide at
brake drum here.
ge
brake band
0.5~0.7mm
(35/6q")
In playback mode, this
clearance should even.
Note: If the brake-release stroke is long, the
brake band may bend at the position
shown with *. Be sure not to bend the
brake band.
After the adjustment, apply a suitable locking
compound to the adjustment screw.
Brake Adjustment (2) and Brake Torque
Adjustment
Adjust both the supply- and take-up-side brakes.
In stop mode, loosen the adjustment screw
and adjust the position of the brake stopper for
the specified clearance between the brake
stopper and brake lever.
brake stopper
brake lever
After the adjustment, tighten the adjustment
screw and apply a suitable locking compound
to the screw. Adjust hooking
position.
Measure both the forward and backward brake
torques. Adjust spring-hook position for the
specified torques.
backward
1,800—2,500g-cm
(25-34 oz-inch)
600—700 g-cm
(8.5—9.5 oz-inch)
backward torque: adjustment screw
forward
brake arm
forward torque:
reel table

TC-765
Pinch Roller Pressure Check
— playback mode —
1. Place the dial-cord ring between the pinch
roller and pinch-roller cap.
pinch roller pinch-roller cap
t
dial cord (0.5mm dia.)
In playback mode, pull the spring scale on the
center line made by the centers of the capstan
and pinch roller.
3. Slowly return the pinch roller and read the
spring scale just when the pinch roller starts to
rotate.
i :
SF)
®
OOOO
ae = Senn eee
pinch roller
spring scale
800 g—1,200 g,
(1lb 120z—2 lb 10 0z) \
pressure difference Pull.
between the take-up
and supply sides:
within 200g (7 02)
Forward Torque Adjustment
; ; hub for measurement
Remove the side board (right).
Apply the rated ac voltage to the AC IN.
Set the TAPE SPEED switch to 19 cm/s and
REEL SIZE switch to 10%.
In playback mode, adjust RV703 for the
specified torques.
Set REEL SIZE switch to 7 and check torques.
2 Set the tension
REEL
SIZE
switch
arm
to
ON
position
using a rubber band
etc.
"
soz | 520-580g0m | 260-320 gem PRES Cees
(7.3-8.0 oz inch} | (3.6-4.4 oz inch}
380-440 g-cm 180—240 g-cm
(5.3-6.1 oz-inch} | (2.5—3.3 oz-inch}

TC-765 |
Supply Reel Back Tension Adjustment
Note: This adjustment requires a ultra-low
frequency audio signal generator. If the
signal generator is not available, do not
attempt this adjustment.
Remove the side board (left).
Apply the rated ac voltage to AC IN.
Set RV702 to the fully-counterclockwise stop.
Put a torque meter on the supply reel tape.
Unsolder the RED and WHT lead wires from
the FG at the system control board.
Set the signal generator’s frequency to 20.2 Hz
and attenuator to -20dB.
Connect the signal generator to the points from
where the two lead wires are unsoldered in
step 5.
Set REEL SIZE switch to 10% and TAPE
SPEED switch to 19 cm.
In playback mode, adjust RV702 for specified
torque.
Back tension torque
150 g:cm (2.1 oz inch)
120 g-cm (1.65 oz inch)
Change the audio signal generator’s frequency
to 7.14Hz and check the torque meter reeding.
Torque meter reeding
280-340 g-cm
(3.9—4.7 oz-inch)
220—280 g:cm
(3. 1—3.8 oz inch]
Fast Forward and Rewind Back Tesnion Check
Apply the rated ac voltage to AC IN.
Turn either the left- or right-side tension arm
on using a rubber band.
Put a torque meter on the supply reel table.
In fast forward mode, pull the torque meter in
the arrowed direction at a speed of 19—9.5 cm/s
and read the fast forward back tension on the
torque meter.
Put a torque meter on the take-up reel table.
In rewind mode, pull the torque meter and
read the rewind back tension as in step 3.
supply reel table take-up reel table
torque meter
Set the tension _
arm to ON position
using a rubber band.
e200 0000 o
REEL SIZE switch
sore
710-150 9-cm 80-120 g-:cm
(1.6-2.0 oz-inch) | (1.15-1.6 oz-inch)
70—110g-cm 50-90 9:cm
(1.0—1.5 ozinch}) | (0.7—1.2 oz inch}

3-2. SYSTEM CONTROL CHECK
System Control Check
Setting:
REEL SIZE switch: 10%
TAPE SPEED switch: 19cm
TIMER switch: OFF
MONITOR switch: TAPE
PB LEVEL control: center click
REC MONITOR MUTE switch: OFF
INPUT SELECT switch: LINE
(AEP, UK, PX model)
REC MODE switches: released positions
Put the 10%-inch blank tapes on the set.
Checking:
1.
Turn POWER switch ON. The VU meter lamps
should light up.
Depress REC MODE switches, The L-side lamp
should light up when the L-side REC MODE
switch is depressed, and the R-side lamp should
light up when the R-side REC MODE switch is
depressed. And the record button lamp should
put on and off repeatedly.
Depress the pause button. The pause button
lamp should light up.
Depress the record and forward buttons simul-
taneously. The record button lamp should
turn from flickering to ON. At the same time,
the forward button lamp should light up.
Press the pause button. The pause button lamp
should turn off and the pinch roller should
press the capstan and become in forward record
mode.
Depress the fast forward button. The set should
become in the fast forward mode. In this mode,
the record button lamp flickers, forward button
lamp turns off and the fast forward button
lamp turns on.
Depress the rewind button. The set should
become in the rewind mode. In this mode, the
fast forward button lamp should turn off and
rewind button lamp turns on.
Depress the forward button. The rewind button
lamp should turn off and forward button lamp
turns on. The tape should once completely
stop traveling, and then become in the forward
mode.
10.
11.
12.
| TC-765
The set should become in the stop mode only
when both the tension arm microswitches turn
off. The set should not become in the stop
mode when one of the tension arm micro-
switches turns off.
Turn TIMER switch ON. Turn POWER switch
OFF once, and two to three second later turn
POWER switch ON. Now the set should
become in the forward record mode auto-
matically.
With REC MODE switches released (i.e., in the
playback positions), perform the same pro-
cedure as shown in step 10. The set should
become in forward mode automatically.
Place the set in the forward record and simul-
taneous monitoring mode. Turn REC MONI-
TOR MUTE switch on the rear panel ON.
Now the signal should not come out from
LINE OUT jacks.
Rewind the recorded portion of the tape and
place the set in the forward mode. Now the
signal should come out from LINE OUT jacks.
Turn REC MONITOR MUTE switch OFF.
Depress the forward and pause buttons. Move
the recorded portion of the tape back and
forth. Sound signal should come out from
LINE OUT jacks.

TC-765 |
3-3. ELECTRICAL ADJUSTMENTS
Note: The adjustments should be performed in
the order given in this service manual.
The adjustments should be performed
for both L-CH and R-CH.
Standard Record:
Set the REC LEVEL control for the specified
output level.
MIC 0.77 mV (-60dB)
af osc
HEADPHONES 82 35mV {-27dB)
LINE OUT 100 k2. 0.44V (-5 dB)
Control and Switch Settings:
Unless otherwise specified, set the controls and
switches as follows.
input level.
The position to
produce the rated
LINE OUT level
with rated LINE
The position to
produce the rated
MIC REC VOL LINE OUT ievel
with rated MIC
LINE REC VOL
IN level.
POWER
REEL SIZE
TAPE SPEED
TIMER
ON
7
19
OFF
MIC ATT |
TAPE SELECT (BIAS) |__| MED _|
TAPE SELECT (EQ) | ~~ | SPECIAL |
REC MODE | PB | REC
INPUT SELECT LINE LINE
(AEP, UK, PX model)
aor a

| TC-765
B+ Voltage Adjustment Tape Speed Adjustment
Adjustment Location: Procedure:
— function button board — Mode: playback
are checker
FM-30
or
digital frequency
test tape counter
SPC-4
(4kHz, 0dB)
LINE OUT
Use a non-metallic screwdriver. Adjust RV901
(19 cm/s) and RV902 (9.5 cm/s) for 0% checker
or 4,000 Hz (19 cm/s) and 2,000 Hz (9.5 cm/s)
counter readings.
Specification:
3,970—4,030 Hz-(19 cm/s)
oO15 2 1,985—2,015 Hz (9.5 cm/s)
Frequency difference between beginning and
end of tape:
19cm/s: within 0.5% or 20 Hz
9.5 cm/s: within 0.5% or 10Hz
[24V ac| vend Ee iS
Adjustment Location:
left side
right side
ae)
om
C4]
RV901 (19.cm/s}
RV902 (9.5 cm/s}

TC-765 |
Playback Head Angle Adjustment
Procedure:
Mode: playback
SONY J-19-F2
(4th tone, 12.5kHz, -10dB)
LINE OUT (L & R)
Loosen the adjustment screws qd) and Q and
adjust the position of the PB head by moving
the screw @) in the arrowed direction for the
highest VTVM reading.
After the adjustment, apply a locking com-
pound to the screws.
Note: Slightly touch the supply reel and at
this time the VTVM reading deviation
should be less than 1 dB.
Adjustment Location:
— head base —
angle adjustment screw Q)
angle adjustment screw @)
Playback Head Azimuth and Phase Adjustment
Procedure:
1. Mode: playback
SONY J-19-F2
(4th tone, 12.5kHz, -100B)
LINE OUT (L & R)
Turn the adjustment screws of the PB head
for the highest VTVM reading. If the highest
peaks for L and R do not coincide, place the
adjustment screw to the point where both L
and R outputs are same and within 1 dB from
the peaks.
Note: The two adjustment screws are so con-
structed to react each other. When one
side screw is loosened, tighten another
screw in the same angle.
2. Mode: playback
SONY J-19-F2
{4th tone, 12.5kHz, -10dB)
L-channe! 100k2 oscilloscope
On the oscilloscope
Y}®D/O} ©
in-phase | 30° 90° |move than 90°
as
Note: Difference between the highest levels
of L and R and the finally adjusted level
* should be within 1 dB.
Adjustment Location:
— head base —
azimuth adjustment screws
hexagonal socket () [1.5mm]

TC-765
Playback Frequency Response Adjustment Playback Level Adjustment
Procedure: Procedure:
Mode: playback Mode: playback
PLAYBACK HEAD switch: 2 TRACK
SONY J-19-F2
(ist tone, 400 Hz, 0dB)
SONY J-19-F2
(2nd tone, 400 Hz, -10 dB)
(3rd tone, 10kHz, -10 dB)
(4th tone, 12.5 kHz, -10 dB)
LINE OUT (L & R)
LINE
OUT
(L
&
R)
[Adjust
VTVM
reading
RV104 (L-CH) 0.44V (-5 dB)
Adjust
the
pattern
connections
to
obtain
the
:
cd
RV304
(R-CH)
paler
yt
a5
specified values.
: Note: Level difference between L and R
Playback
Level
difference
from
400
Hz
channels
should
be
within
1
4B.
10 kHz Ad
12.5
kHz
within
+2
dB
Adjustment
Location:
— audio amp board —
Adjustment
Location:
AV104
(L-CH)
RV304
(R-CHI
— audio amp board —
pattern connection pattern connection
Note: After this adjustment perform the play-
back level adjustment.

TC-765 |
VU Meter Calibration
Setting:
Record Head Angle Adjustment
Setting:
MONITOR
switch:
SOURCE
MONITOR
switch:
TAPE
Procedure:
1. Mode: record
af osc
€ attenuator 6002
oO
RV106 (L-CH)
RV306 (R-CH)
Adjustment Location:
— audio amp board —
RV106 (L-CH)
Procedure:
Mode: record and simultaneous playback
PLAYBACK HEAD switch: 2T REC
SONY PLN-370B
(blank tape)
MIC LINE OUT
400
Hz,
0.77mV
(-60dB8})
0.44V
(-5aB)
MIC
(L
&
R}
15kHz, 77nV (~80 dB)
LINE OUT (L & R)
Loosen the adjustment screws qd) and @.
Correctly position the record head by moving
the adjustment screw Q) in. the arrowed direc-
tions for the highest VTVM reading.
Note: Slightly touch the supply reel and at
this time the VTVM reading deviation
should be less than 1 dB.
After the adjustment, apply a suitable locking
compound to the screws,
Adjustment Location:
-- head base —
angle adjustment screw @)
RV306 (R-CH)
angle adjustment screw @)

Record Head Height and Zenith Adjustment
Setting:
MONITOR switch: TAPE
Procedure:
Mode: ‘record and simultaneous playback
PLAYBACK HEAD switch: 2 TRACK
allel SONY SLH-S1
oe) {blank tape)
O| _ attenuator
Es
MIC (L & R)
1kHz, 0.77mV (-60dB) _
Turn the height and zenith adjustment screws
for the highest VTVM reading.
LINE OUT (L & R)
Adjustment Location:
— head base —
height/zenith adjustment screws
Record Head Azimuth and Phase Adjustments
Setting:
MONITOR switch: TAPE
Procedure:
When a simplified test is made, follow Pro-
cedure 1. When an oscilloscope is available,
employ Procedure 2.
Note: The two adjustment screws are so con-
structed to react each other. When one
side screw is loosened, tighten another
screw in the same angle.
1. Mode: record and simultaneous playback
af osc
SONY SLH-S1
(blank tape)
Mic (lL & R)
15kHz, 77nV (-800B)
LINE OUT (L & R)
Turn the adjustment screws for the highest
VTVM reading. If the highest peaks for L and
R do not coincide, place the adjustment screws
to the point where both L and R outputs are
same and within 1 dB from the peaks.
2. Mode: record and simultaneous playback
af ose
SONY SLH-S1
€) (blank tape}
) attenuator
MIC (L & R} .
15kHz, 77nV (-80d0B) _ —- —
-
-
oscilloscope
LINE OUT
On the oscilloscope
QO}®|OQ} ©
in-phase} 30° 90° {more than 90°
ee
Note: Difference between the highest levels
of L and R and the finally adjusted level
should be within 1 dB.
Adjustment Location:
— head base—
azimuth adjustment screws
(hexagonal socket) [1.5mm]
|

TC-765 |
Record Bias Adjustment
Setting:
MONITOR switch: TAPE
Procedure:
Mode: record and simultaneous playback
af osc
@) attenuator
MIC (L & R)
1 kHz, 0.77mV (-60 dB)
SONY SLH-S1
(blank tape)
_
LINE OUT (L & R)
As trimmer capacitor C135 (L-CH) or C335
(R-CH) is slowly turned clockwise, VTVM
reading will go up to a maximum and then start
falling again. Adjust the capacitor until VTVM
reads 0.5 dB below and beyond the maximum
reading.
maximum reading
0.5dB {allowance: 0—-1 dB)
appropriate point
— clockwise turn of trimmer capacitor
Adjustment Location:
~— audio amp board —
ages
Poy
PRON rs
ne
PATI
Ped
Os
A ws
Dey
a
fry sees
oo og, eeee
cfs CIEE
Tee Rel Vegans.
C135 (L-CH) C335 (R-CH)
Record Level Adjustment
Setting:
MONITOR switch: TAPE
Procedure:
Mode: record and simultaneous playback
af osc
SONY SLH-S1
(blank tape)
MIC (lL & R)
1 kHz, 0.77mV {-6008)}
LINE OUT (L & R}
0.44V (-5 dB)
RV103 (L-CH)
RV303 (R-CH)
Adjustment Location:
— audio amp board —
RV103 (L-CH)
eo avetes®
eoecess
RV303 (R-CH) :

| TC-765 TC-765 |
Dummy Coil Adjustment
Record Equalizer Adjustment Record Bias Trap Adjustment
Setting:
MONITOR switch: TAPE
Setting:
MIC REC control:
LINE REC control:
Setting:
MONITOR switch: TAPE
0
0
Procedure: Procedure:
Procedure: Mode: record and simultaneous playback
Mode: record and simultaneous playback
Mode: record
f af osc
—
SONY
SLH-S1
SONY
SLH-S1
6)
(blank
tape)
ee
a)
(blank
tape)
ee é
| _attenuator fe O| _ attenuator
oo 1 bee
ott,
tg
MIC (L & R) wer |
1.
1kHz,
25uV
(-90dB)
sae.
‘
2 25kHz, 25uV (-900B)_ —
eee
_
_
k LINE OUT (L & R)
stereo record and Record VIVM
simultaneous 5
reading.
play back
!
VOM (ac range)|
|
|
|
|
\L-CH
ot ds-- J RCH
L106 (L-CH) minimum
L306 (R-CH)
Adjustment Location:
L102 (L-CH) Same LINE OUT
and level at both
L302 (R-CH) frequencies. L channel record
and simultaneous
play back
same VTVM
reading as in
R
channel
record
step
1.
and simultaneous
playback
Level-difference allowance of 25 kHz signal
from 1kHz: OdB—-3dB
Adjustment Location:
Adjustment Location:
— audio amp board —
— audio amp board —
L102 (L-CH) L302 (R-CH) Saudia einp Bosra =
L107 L307
(adjustment for R-CH) (adjustment for L-CH)
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£106 (L-CH) L306 (R-CH)
SONY-00527 / DRUCK 7

TC-765 TC-765 |
SONY-00527 / DRUCK 8
Dummy Coil Adjustment
Setting:
MONITOR switch: TAPE
Procedure:
Mode:
record and simultaneous playback
af osc
SONY SLH-S1
a) (blank tape)
‘Oo attenuator
aan |
MIC (L & R) wo
20kHz, 25uV (-90dB) _ — —
_
_
E
LINE OUT (L & R)
stereo record and
simultaneous
play back
Record VTVM
reading.
L channel record
and simultaneous
play back
same VTVM
reading as in
step 1.
R channel record
and simultaneous
playback
Adjustment Location:
— audio amp board —
L307
L107
(adjustment for L-CH)
(adjustment for R-CH)
seen ®
sesere
r
een °
: