Sony TC-RX77 User manual

TC-RX77/RX7TTES
SERVICE MANUAL
Dolby noise reduction manufactured under license from
Dolby Laboratories Licensing Corporation.
“DOLBY” and the double-D symbol 00) are trademarks of
Dolby Laboratories Licensing Corporation.
4-track 2-channel stereo
Approx. 90 sec. (with Sony C-60
Recording system
Fast-winding time
cassette)
Bias AC bias
Heads Erasing head x 1 (ferrite head)
Playback/Recording head x 1 (LA
head)
Motors Capstan motor x 1 (DC servo motor)
Reel motor x 1 (DC motor)
ASIST (mechanical drive) motor x 1
(DC motor)
Signal-to-noise ratio (at peak level)
Type IV (Sony METAL-SLT) | 59dB | 67 4B
Type Il (Sony UX-S) 58dB | 66dB
Total harmonic distortion
1% (with Sony METAL-SLT cassette)
Frequency response (DOLBY NR OFF)
20- 20,000Hz (+ 3db,/EC)
(US, Canadian models)
25-19,000Hz (+ 3db,JEC) (AEP)
Type Il cassette 25 - 17,000 Hz (+3 dB, IEC)
(Sony UX-S)
Type | cassette 25 - 16,000 Hz (+3 dB, IEC)
(Sony HF-S)
Wow and flutter +0.09% W. Peak (IEC)
0.06% WRMS (NAB).
+0.16% W. Peak (DIN)
Type IV cassette
(Sony METAL-SLT)
Dolby NR switch OFF B-Type | C-Type
ON ON |
— US Model
Canadian Model
TC-RX77TES
AEP Model
TC-RX77
Model Name Using Similar Mechanism TC-RX70/RX70ES
Tape Transport Mechanism Type TCM - 200R6
hg s
Inputs
(phone
Outputs
Line outputs
(phono jacks)
Headphones
(stereo phone
jack)
Line inputs
(phono jacks)
Microphone inputs
77.5 mV
Input impedance | 47 k ohms
Sensitivity (For a | 0.25 mV
low-impedance |
microphone)
jacks)
Rated output level] 0.32 V ata load
impedance of 47
k ohms
Load impedance | Over 10 k ohms
Output level 0-1.25 mW ata
load impedance of
32 ohms
General
Power requirements
RX77ES : 120 V AC, 60Hz (US, Canadian models)
RX77 =: 220V AC, 50/60Hz (AEP model)
Power consumption 20W
Dimensions Approx. 430 x 123 x 300 mm (w/h/d)
(17 x 4% x 117% inches)
including projecting parts and controls
Weight Approx. 4.7 kg (10 Ibs 6 02)
Supplied accessory
Audio connecting cords (2)
Design and specifications subject to change without notice.
STEREO CASSETTE DECK
SONY.

TC-RX77/RX77ES
TABLE OF CONTENTS
Section Title Page
Specification S/S BS Sea a eee er eser ee rete: eve eens ewe Nec ene <a tenerer ole al Gee eee 1
; Model Identification wey el ole tenes te eS" SU SNS. SSUES Slee ws ere ere reset eieven ese. 2
Safety Check-Out BOBO bib SNS Ow co Le: WLS Ge Ver ONS eee cede. 8 Je~eueitior enete: ® 2
1 GENERAL 6 80s eiide ated ceiieie oe ecloew ind B9G 56 Res 3
2: DISASSEMBLY str xe kite o0es Os eee Eas eet kos 4
3 ADJUSTMENTS <6 6 teria tees his eet ely g sei alee be 7
3-1. Mechanical Adjustment ++++++++sseeresereree t
3-2. Electrical Adjustment 6 Wns ele eet eats, oC ew onal eke ere wisete 7
. DIAGRAMS
4-1. Semiconductor Lead Layout:::t+rrrrste eee 11
4-2, Circuit Boards Location -+++++rssee reste cers 11
4-3, Printed Wiring Boards -++++++++seeee reece 12
4-4, Schematic Diagram aie aiid Gute Sie vale Loiieyecene iene tobe peceneceie 17
EXPLODED VIEWS <tesesc0esxetaceatver sieht cass 16
5-1. Front Panel Section -s+ssserssee ee eeeeeeeees 23
. 5-2, Chassis Section EO RO a eR RC RT REN Re Ae 24
5-3. Mechanism Section (TCM~200R6) «++++++++> 25
5-4. Mechanism. Section (TCM-200R6) ---+-:++++- 26
_ ELECTRICAL PARTS LIST <:--:--ceececcreceeenee 27
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK A OR DOTTED
LINE WITH MARK A ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.
ATTENTION AU COMPOSANT AYANT RAPPORT
A LA SECURITE!
LES COMPOSANTS IDENTIFIES PAR UNE MARQUE /\
SUR LES DIAGRAMMES SCHEMATIQUES ET LA LISTE
DES PIECES SONT CRITIQUES POUR LA SECURITE
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR DES PIECES SONY DONT LES
NUMEROS SONT DONNES DANS CE MANUEL OU
DANS LES SUPPLEMENTS PUBLIES PAR SONY.
SAFETY CHECK-OUT
After correcting the original service problem,
perform the following safety check before releasing
the set to the customer:
Check the antenna terminals, metal trim, ‘“‘metallized”’
knobs, screws, and all other exposed metal parts for
AC leakage. Check leakage as described below.
LEAKAGE TEST
The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5mA (500 microampers). Leakage
current can be measured by any one of three
methods.
1. A commercial leakage tester, such as the
Simpson 229 or RCA WT-S40A. Follow the
manufacturers’ instructions to use these instru-
ments.
2. <A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.
3. Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The “limit” indication is 0.75 V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)
To E. xposed Metal
Parts on Set
LAs
0.15 uF voltmeter
A 628)
= Earth Ground
Using an AC voltmeter to check AC leakage.

TC-RX77/RX77ES
SECTION 1
GENERAL
This section is extracted from
instraction manual.
Identification of Front Panel Parts
*Remote control sensor
30
beste at
@
MEADE MNES
Dae We
@
For details, refer to the page number indicated in @.
Tape operation buttons
€ (leftward fast winding) button
bP (rightward fast winding) button
i (stop) button
~@ (reverse play) button
w- (forward play) button
HE PAUSE (pause) button
O REC MUTE (record muting) button @
(4] POWER switch
[9]
MPX FILTER button @®
[2] Cassette holder
&]
BALANCE control @
Counter buttons
RESET button ©
MEMORY button @ ©
al
REC (recording) LEVEL control @ ®
fs
PHONE (headphones) LEVEL control @
[4] LINEAR COUNTER ©
[5] PEAK LEVEL METER ®
les]
HEADPHONES jack (stereo phone jack) @
ra
DOLBY NR (noise reduction switch) @ @
@ REC (record) button
[8] & OPEN/CLOSE button
[6] DISPLAY MODE button @
IN
FADER button @
ARL (automatic recording level) control and
indicator @
[o0
*Remote control sensor
You can remotely control this cassette deck with:
fal
MICROPHONE jacks (phone jacks)
fa]
BIAS control ®
— Aremote commander that came with a Sony amplifier
or receiver if it has the tf mark and cassette deck
control capability.
— An optional Sony remote commander with the lf mark
and cassette deck control capability.
YorYahahivescheceye mee) MM a{=t;) am ov: 1012) Mm ons) 8 C3)
LINE IN (line input) jacks
'——' CONTROL-S input
Connect to the CONTROL-
S terminal of a Sony
amplifier or receiver for
remote control.
(US, Canadian model)
AC power cord
TIMER switch ®
20} DIRECTION mode switch @ @
Features
For higher quality recording/playback
* The Dolby HX PRO* system which improves the linearity
of the tape’s high-range response during recording.
¢ B and C type Dolby NR* systems which reduce tape
noise.
« Bias calibration to achieve the optimum bias current
setting for any tape.
For your convenience
* Quick reversing at the end of a tape to minimize
interruptions during playback and recording.
* The AMS and Memory Play functions which provide
easy access to a desired selection.
* Automatic recording level adjustment for one-touch
protection against distortion.
* Timer-activated playback and recording through the use
of an optional timer.
* Automatic switching between line and microphone
input when recording with a microphone.
¢ Display mode button which allows you to select normal
display, counter only or display off.
For easier operation
« Fade-in and Fade-out functions to start and end
recordings with a professional touch.
« Easy-to-read digital linear counter which shows the
elapsed recording or playing time.

TC-RX77/RX77ES |
Note: Follow the disassembly procedure
in the numerical order given.
Unscrew the four case attachment screws M3 x 8 and
remove the upper case.
MAIN BOARD
SECTION 2
DISASSEMBLY
@ + BVTT3 x8
MECHANISM
@
CASSETTE
LID
ASSY
® + BVIT3x6
@ + BVTT3 x 8
@ +BVIT3x6

CASSETTE HOLDER
@ Push LEVER (LIFTER) in the
direction of arrow and remove
CASSETTE HOLDER.
LEVER JOINT Q CASSETTE HOLDER
’ SHAFT (LEFT) Cael
@TENSION SPRING (CASSETTE HOLDER) @ STOPPER WASHER
ORNAMENTAL PLATE
@ Push LEVER (LIFTER) in the direction
of arrow and remove ORNAMENTAL
PLATE. ;
@ + BrP26x6
PINCH LEVER/HEAD
@ Removal of HEAD
ad ©
at, ‘Ses @ LEVER (FR)
ESN Seas / @ WASHER
Oo gk ie
Release caw!
3 (
VN.
© HEAD ‘G
: ~ NX MG
Release ie GP?
claw.
\
@ LEVER (PINCH R)
@ LEVER (PINCH F)
= hes
MOTOR PULLEY
Turn MOTOR PULLEY by a finger in the
direction of arrow @ and confirm that
HEAD has turned in the direction of arrow (5).
CAPSTAN MOTOR/ FLYWHEEL
TC-RX77/RX77ES
ie
LB Hook BELT here temporarily
B2.6 x 3 \ when reassembling.
eas @ + PTPWH2 x 25
@ FLYWHEEL
oe @ REV)
@CAPSTAN MOTOR
@ BRACKET (THRUST @+ BTP2 x 18
RETAINER
R)
35—@
+
BVTP2.6
x
8
REEL and ASSIST MOTORS
@ + BTP2x 18
Align BOSS of MODE CAM to
the point when reassembling.
0+ B2.6x6
LEAL) SD
ANZ YR SELECTION LEVER
MODE CAM | LB
\, Hook BELT here
temporarily when
reassembling.
Align the line on MODE CAM to
the tip of SELECTION LEVER.
@ ASSIST MOTOR
SPACER (MOTOR) = grackET (MOTOR R)
@ REEL MOTOR ASSY
@ REEL MOTOR BOARD
ia; eae

TC-RX77/RX77ES |
SECTION 3
ADJUSTMENTS
3-1, MECHANICAL ADJUSTMENTS
PRECAUTION
1, Clean the following parts with a denatured-
alcohol-moistened swab :
record/playback head pinch roller
erase head rubber belts
capstan idler
2, Demagnetize the record/playback head with a head
demagnetizer,
3. Do not use a magnetized screwdriver for the ad-
justments,
4, After the adjustments, apply suitable locking compound
to the parts adjusted,
TORQUE MEASUREMENT
CQ-102C [80 - 60g cm (0.42 — 0.8302 inch)
F
WD -
WD
CQ- 102C 1—5g+cm (0.014 — 0.0690z + inch)
Back tention
REV =
TREV.——sT«Ss CQ 102RC_—« [30 - 60g +cm (0.42 — 0.830z* inch)
REV
. CQ~ 102RC
Back tention
FF, REW CQ~-201B 65 —90*cm (0.9 — 1.2502 « inch)
1—5gecm (0.014 — 0,0690z + inch)
3-2, ELECTRICAL ADJUSTMENT
Note: The adjustment should be performed in the order given
in the service manual. As a rule, adjustments about
playback should be performed before those about recording.
The adjustments should be performed for both L-
CH and R-CH,
* Switches and controls should be set as follows unless
otherwise specified,
DOLBY NR switch : OFF
DIRECTION switch oe
¢ Standard Record:
Deliver the standard input signal level to the input jack
and set the REC LEVEL control to obtain the standard
output signal level,
—Record Mode—
AF OSC
VTVM
me) 10k Q
O Attenuator
e—_—
oO O
I] ooo |
ee |
LINE. IN LINE OUT
Standard Input Level
input terminal LINE IN
Standard Output Level
Test Tape
P-4-A100 10kHz, —10dB Azimuth Adjustment
P-4-L300 315Hz, 0dB PB Level Adjustment
3kHz, 0dB Tape Speed Adjustment
Test Mode
1, Put the set into the test mode by shorting test point TP801
(TEST) of the main bord during the set is turned off.
2. Remove the short after the Electrical Adjustment is completed.
Record Playback Head Azimuth Adjustment
Procedure :
1, Mode: FWD playback
Test tape
P-4-A100
(LOkHz, —10dB) VTVM
LINE OUT
2. Turn the adjustment screw for the maximum output
levels, If these levels do not match, turn the adjustment
screw until both of output levels match together within
1dB. ,
L-CH
k
a within
1dB
R-CH
peak
Screw
position

3.
Phase
Check
Adjustment
Location
:
Mode
:
playback
motor
rear
side
test tape variable resister
P-4-A100
(10kHz, — 10dB) oscilloscope
LCH ATK Q
LINE OUT
Screen pattern
in phase 45° 90° 135° 180°
——_-—————”
good wrong
4, Set in the REV mode and repeat the step 1-8,
5, After the adjustment, lock the screws with locking
Playback Level Adjustment
compound,
Procedure :
Adjustment Location : Record/Playback head Mode : playback
test tape
P-4-L300
(315kHz, 0dB)
VTVM
FWD REV
Sd
Adjustment
screw
LINE
OUT
Adjust RV101 (L-ch) and RV201 (R~ch) so that the reading on
Tape Speed Adjustment VTVM meets the adjustment limits below.
Setting :
test pin TP801 : short Adjustment Limits :
LINE OUT level: —7.7dBs(m) + 0.5dB(0.3~0.34V)
Procedure :
Level difference between channels: less than 0.5dB
Check that the LINE OUT level does not change even if Playback
and Stop operation is repeated several times.
Mode : playback
test tape Adjustment Location: Main board
WS-48B
(3kHz, OdB)
jo
frequency counter
1. Set to FWD playback mode.
2. Adjust motor rear side (variable resistor) so that the frequency
counter reading becomes 3,000 + 15Hz.

Bias Current Adjustment
Procedure :
LINE IN
(no signal)
CS-413 blank tape
digital voltmeter
47k
L-CH
oO
x
Ana ces |
TP301
B+ (+7.5V)
1. Set RV103 and RV203 to mechanical center and turn the set
recording mode.
2. Connect digital voltmeter as shown by the following table.
38. Adjust the following transformers for the minimum readings
on the digital voltmeter.
Adjustment Part
@ and @, TP301 T101 not more than
.® and ©, TP301 T201 130mV
Adjustment Location: Main board
Record Bias Adjustment
Setting :
REC LEVEL control: Standard Record (See page 7.)
test pin TP801: short
Procedure :
1, Mode: record
sine
CS-123
10k
Q
blank
tape
ae)
attenuator
Of
ny
o—o
I]
ooo
|
|
eee
|
LINE
IN
1)
315Hz
2)
10kHz
24.5mV(—
30dBs(m))
2. Mode: playback
recorded
portion
po
Playback the signal recorded in step 1.
Confirm that the 10kHz playback output is 0+0.5dB relative to
the 315Hz output. If necessary, adjust RV103 (L-ch) and RV203
(R-ch) for repeat the steps given above.
VTVM
LINE OUT
Adjustment Location: Main board
Record Level Adjustment
Setting:
REC LEVEL control: Standard Record (See page 7.)
test pin TP801: short
Procedure :
1, Mode: record
AF OSC
€) attenuator
(oe)
VTVM
LINE OUT
LINE IN
315Hz, 32.2mV(— 27.7dBs(m))
2. Mode: playback
recorded
portion
LINE OUT
3. Playback the signal recorded in stepl.
Confirm that the signal level is within the adjustment limits
below. If necessary, adjust RV102 (L-ch) and RV202 (R-ch)
repeat the stepl-2.
Adjustment Limits: —27.7dBs(m) + 0.5dB(80.4~34.2mV)
Adjustment Location: Main board
Quick Reverse Sensitivity Adjustment
Conditions :
DIRECTION MODE switch : y=
digital voltmeter
Adjustment procedure:
Quick reverse
adjustment tape
(Leader of the ‘ nee
black cassette
tape) TP802
Connect the digital voltmeter to test point TP802.
2. Load quick reverse adjustment tape and play back the leading
portion in FWD mode.
3. Adjust the RV801 for 4.5+0.5V reading on the digital
voltmeter.
Play back quick reverse adjustment tape in FWD mode again.
Confirm that the reading on the digital voltmeter is “L” level
at the magnetic portion of the tape.
6. Confirm that the tape stop around the tape end (boder of
the leading and the magnetic portions).
Adjustment Location: Main board
220i:

Adjustment Parts Location
—Main board -
RV102 (L-ch)
RV202 (R-ch) Record Level
TP801
Test
Mode
point
RV101
(L-ch)
RV201
(R-ch)
Playback
Level
TP802
Quick Reverse Test point
T101 (L-ch)
7201 ee Bias Current
RV801 Quick Reverse
TP301
Bias Current Test point
RV203 (R-ch)
RV103 ah Record Bias
240 =

SECTION 4
DIAGRAMS
4-1. SEMICONDUCTOR LEAD LAYOUTS
DTA114ES RBA402 SEL2210S-C
DTA144ES
DTC114ES
DTC143TS
2SA1175-HFE tong short
2SB1116A-L
2SC2603~- EF node — cathode
28C945-P
28D1020-HFE aad
peseall GP2S22B
HZS7AIL
UZL~-7H1
UZL-12M1 eneaaha
| CaTuocE
emitter 4 Y
ANOCE
2SB1370~-EF
28D1312-K
10E2N
21DQ05
4-2. CIRCUIT BOARDS LOCATION
POWER BOARD
REEL MOTOR BOARD
MD BOARD
SW BOARD
MAIN BOARD
HEAD TRANSLATION
BOARD
DISPLAY
BOARD
REC
LEVEL
BOARD
DOLBY “BAL BOARD HEADPHONES BOARD
MIC BOARD
a
4-3. PRINTED WIRING BOARDS
4-3-1.
FORMER
TYPE
(Main
Board
US
model
and
Main
Board
No.
1-638-124-12
only.)
TC-RX77/RX77ES
posto eo oe Bie = = a5
are se tN sk [out PLNe |
| yy 4a ow yp 0 6 Gee
KMAIN BOARD} DFO, OF©,, _ a6 38 28 1 Jensoe
SERENE, ag eneaee ape Montane oN TIE
Sey CE ARE ASOD BESS ET EO
i
‘
conten:
cron AR AR RA NE, SEES
<oy
|- 638-124 )
ney oem