Sony XR-4759RDS User manual

MICROFILM
UK Model
SERVICE MANUAL
FM/MW/LW CASSETTE CAR STEREO
SPECIFICATIONS
Model Name Using Similar Mechanism XR-3740
Tape Transport Mechanism Type MG-52A-135
XR-4758RDS/4759RDS
Photo: XR-4759RDS

– 2 –
TABLE OF CONTENTS
1. GENERAL
Location of Controls........................................................ 3
2. DISASSEMBLY ......................................................... 4
3. ASSEMBLY OF MECHANISM DECK ........... 6
4. MECHANICAL ADJUSTMENTS ....................... 12
5. ELECTRICAL ADJUSTMENTS
Test Mode ........................................................................ 12
Tape Deck Section ........................................................... 13
Tuner Section................................................................... 13
6. DIAGRAMS
6-1. IC Pin Function Description............................................ 16
6-2. Printed Wiring Boards – MAIN Section – ..................... 18
6-3. Schematic Diagram – MAIN Section –........................... 21
6-4. Printed Wiring Board – KEY Section – ......................... 27
6-5. Schematic Diagram – KEY Section – ............................ 29
7. EXPLODED VIEWS ................................................ 34
8. ELECTRICAL PARTS LIST................................ 38
SERVICING NOTES
Flexible Circuit Board Repairing
•Keep the temperature of the soldering iron around 270 ˚C dur-
ing repairing.
•Do not touch the soldering iron on the same conductor of the
circuit board (within 3 times).
•Be careful not to apply force on the conductor when soldering
or unsoldering .
Notes on chip component replacement
•Never reuse a disconnected chip component.
•Notice that the minus side of a tantalum capacitor may be dam-
aged by heat.

– 3 –
SECTION 1
GENERAL This section is extracted
from instruction manual.

– 4 –
Note: Follow the disassembly procedure in the numerical order given.
FRONT PANEL ASS’Y
SECTION 2
DISASSEMBLY
1 Push the button
(release).
A
2 Remove the front panel ass’y
to the direction of the arrow A .
COVER ASS’Y
2
1
3 cover ass’y
1
2

– 5 –
MAIN BOARD, HEAT SINK
1 three screws
(PTT2.6 × 6)
5 screw
(PTT2.6 × 6)
6 mechanism deck
(MG-52A-135)
4 flexible flat cable
(CN351)
1 three screws
(PTT2.6 × 6)
2 sub panel
3 connector
(CN352)
1 screw
(PTT2.6 × 6)
3 main board
1 two screws
(PTT2.6 × 6)
2 two ground point
screws
4 six screws
(PTT2.6 × 8)
SUB PANEL, MECHANISM DECK (MG-52A-135)

– 6 –
SECTION 3
ASSEMBLY OF MECHANISM DECK
Note: Follow the assembly procedure in the numerical order given.
ALIGNMENT OF FRONT SWITCH
GEAR (LDGE)
2 Install the gear (LDG-E).
1 Align hole as shown in the figure.
1 Align ¢ mark on the rotary switch
the position shown in the figure.
chassis (S) ass’y
2 Align hole in the gear (LDG-D) with the
position shown in the figure.
hole

– 7 –
CHASSIS (S) ASS’Y
1. Align ¢ mark on the rotary switch with
hole in the lever (mode).
2. Fit on positions A , B and C and install
the lever (mode).
LEVER (MODE)
hole in lever (mode)
¢ mark on rotary switch
lever (mode)
rotary switch
A
B
C
2 screw (PS2 × 4)
1 chassis (S) ass’y
2 screw (PS2 × 4)

– 8 –
5 step screw (HP)
5 step screw (HP)
2 Fit shaft in groove.
ATS lever
1 Fit in groove.
3 Press the ATS lever.
4 Position the head plate sub
ass’y as shown in the figure.
groove
LEVER (PINCH SELECTION)
HEAD PLATE ASS’Y
1 Align.
2 lever (pich selection)

– 9 –
LEVER (PINCH) ASS’Y
1 Fit shaft of the lever (Pinch) ass’y
in hole on the chassis (M) ass’y and
install the lever (pinch) ass’y.
2 two polyethylene washers
shaft
shaft
B
C
C
B
shaft A
3 Install the spring (pinch press) to shaft A .
Set the ends of spring to B and C .
HOUSING
2 Install the hanger on to
two claws of the housing.
1 Install the catch to the hanger.
7 Holder the hanger by bending the claw.
A part
B part
C part
D part
8 Holder the hanger by
bending the claw.
3 Put the housing
under A part.
4 Fit claw on B part.
6 Fit projections on D part.
5 Fit projections on C part.
hanger

– 10 –
ARM (SUCTION)
1 Fit the lever (LDG-A)
on shaft A – C and install it.
shaft A
shaft B
shaft C
3 two type-E stop ring 2.0
2 Fit the lever (LDG-B)
on shafts A and B and
install.
shaft A
shaft B
LEVER (LDG-A) / (LDG-B)
2 Move the arm (suction) in the arrow
direction and fit on projection.
1 Fit the arm (suction) on the shaft.
projection

– 11 –
GEAR (LDG-FT)
4 Align hole in the gear (LDG-D) with
¢ mark on the lever (LDG-A).
gear (LDG-FB)
hole
gear (LDG-D)
gear (LDG-A)
3 Move the lever (LDG-B)
in the arrow direction.
1 gear (LDG-A)
2 tension spring (lever LDG)
5 gear (LDG-FT)
6 polyethylene washer
GUIDE (C)
2 guide (C)
1 three claws

– 12 –
Mode Torqu Meter Meter Reading
Forward CQ-102C 35–65 g•cm
(0.49–0.90 oz•inch)
Forward CQ-102C 0.5–5.0 g•cm
Back Tension (0.01–0.07 oz•inch)
Reverse CQ-102RC 35–65 g•cm
(0.49–0.90 oz•inch)
Reverse CQ-102RC 0.5–5.0 g•cm
Back Tension (0.01–0.07 oz•inch)
FF, REW CQ-201B 60–200 g•cm
(0.83–2.78 oz•inch)
SECTION 4
MECHANICAL ADJUSTMENTS SECTION 5 ELECTRICAL ADJUSTMENTS
1. Clean the following parts with a denatured-alcohol-moistened
swab: playback head pinch roller
rubber belt capstan
idler
2. Demagnetize the playback head with a head demagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. The adjustments should be performed with the power supply
voltage (14.4 V) unless otherwise noted.
•Torque Measurement
Mode Torqu Meter Meter Reading
Forward CQ-403A more than 60 g
Reverse CQ-403R (more than 2.12 oz)
•Tape Tension Measurement
TEST MODE
This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level and MW Auto Scan/Stop Level adjustments can
be performed easier than it in ordinary procedure.
<Set the Test Mode>
1. Set the “OFF” mode.
2. Push the preset 4 button.
3. Push the preset 5 button.
4. Press the preset 1 button for more than two seconds.
5. Then the display indicates all lights, the test mode is set.
<Release the Test mode>
1. Push the “OFF” button.

– 13 –
FM Stereo Level meter Level meter
signal generator connection reading (dB)
output channel
L-CH L-CH A
B
R-CH L-CH Adjust RV4 on TU1
for minimum reading.
R-CH R-CH C
D
L-CH R-CH Adjust RV4 on TU1
for minimum reading.
set +–
speed checker
or
frequency counte
r
test tape
WS-48A
(3 kHz, 0 dB)
See the adjustment location from on page 15 for the
adjustment.
0 dB=0.775 VTAPE DECK SECTION
Tape Speed Adjustment
Procedure:
1. Put the set into the FWD PB mode.
Speed checker Frequency counter
–1.5 to +2.5% 2,955 to 3,075 Hz
Specification: Constant speed
Adjustment Location: See page 15.
SPEAKER OUT
set
FM RF signal
generator
antenna jack (J1)
0.01 µF
Carrier frequency : 98.0 MHz
Output level : 22 dB (12.6 µV)
Mode : mono
Modulation : 1 kHz, 22.5 kHz deviation (30%)
TUNER SECTION 0 dB=1 µV
Cautions during repair
When the tuner unit is defective, replace it by a new one be-
cause its internal block is difficult to repair.
FM Auto Scan/Stop Level Adjustment
Setting:
SOURCE button: FM
Procedure:
1. Set to the test mode. (See page 12.)
2. Push the SOURCE button and set to FM.
Display
3. Push the preset 3 button.
Display
FM INTRO
REG
INTRO
REG
FM
4 Ω
4. Adjust with the volume RV2 on TU1 so that the “FM” indica-
tion turns to “FM0” indication on the display window.
But, in case of already indicated “FM0”, turn the RV2 so that
put out light “0” indication and adjustment.
Display
Adjustment Location: See page 15.
Carrier frequency : 98.0 MHz
Output level : 70 dB (3.2 mV)
Mode : stereo
Modulation : main: 1 kHz, 20 kHz deviation (26.7%)
sub: 1 kHz, 20 kHz deviation (26.7%)
19 kHz pilot: 7.5 kHz deviation (10%)
INTRO
REG
FM Stereo Separation Adjustment
Setting:
SOURCE button: FM
antenna jack (J1)
4 Ω
SPEAKER OUT
FM RF signal
generator
set +
–
level mete
r
Procedure:
L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.
Specification: Separation more than 26 dB
Adjustment Location: See page 15.

– 14 –
AM RF signal
generator
set
30 Ω
15 pF
65 pF
AM dummy antenna
(50 Ω )
antenna jack (J1)
Carrier frequency : 999 kHz
30% amplitude
modukation by
1 kHz signal
Output level : 33 dB (44.7 µV)
MW Auto Scan/Stop Level Adjustment
Setting:
SOURCE and MODE button: MW
Procedure:
1. Set to the test mode. (See page 12.)
2. Push the SOURCE button and set to FM.
3. Push the MODE button and set to MW.
Display
5. Adjust with the volume RV1 on TU1 so that the “MW” indi-
cation turns to “MW0” indication on the display window.
But, in case of already indicated “MW0”, turn the RV1 so that
put out light “0” indication and adjustment.
Display
4. Push the preset 3 button.
Display
Adjustment Location: See page 15.
FM Signal Meter Adjustment
Setting:
SOURCE button: FM
FM RF signal
generator
Carrier frequency : 98.00 MHz
Output level : 35 dB (56.2
µ V)
Mode : mono
Modulation : no modulation
0.01 µ F
set
antenna jack (J1)
Procedure:
1. Set to the test mode. (See page 12.)
2. Push the SOURCE button and set to FM.
Display
FM INTRO
REG
3. Push the 6 button.
4. Adjust RV1 so that the display indication is “160”.
Display
INTRO
FM
Specification: Display indication: 158 to 162
Adjustment Location: See page 15.
999 @
MW INTRO
3 999
MW INTRO
3 999
INTRO

– 15 –
Adjustment Location:
– SET UPPER VIEW –
TU1
RV1 MW Auto Scan/Stop Level Adjustment
RV2 FM Auto Scan/Stop Level Adjustment
RV4 FM Stereo Separation Adjustment
Tape Speed Adjustment
RV1 FM Signal Meter Adjustment

– 16 –
1 TUNMUT O Tuner muting control pin At muting: “H”
2 AMPON O Power amp power supply control pin
Illumination power supply control pin
3 ILLON O At PW SEL on: ACC on: “H”
At PW SEL off: Power on: “H”
4 PW ON O System power supply control pin
5 AMPMUT O Power amp muting control pin At muting: “L”
6 RC IN1 I Rotary remote commander input pin (A/D input)
7 VDD – Power supply
8 X IN I Main system clock input pin (8 MHz)
9 X OUT O Main system clock output pin (8 MHz)
10 GND – GND
11 XT IN I Sub system clock input pin (32.768 kHz)
12 XT OUT O Sub system clock output pin (32.768 kHz)
13 EX2 – Connected to GND
14 RESET I Reset input pin
15 RDSCKI I RDS clock input pin
16 BU IN I Back up power supply detection pin
17 KEYACK O Key acknowledge signal input pin
18 VOLSO O Data output pin to electrical volume
19 VOLCKO O Clock output pin to electrical volume
20 VOLCE O Chip enable output pin to electrical volume
21 TAPEMUT O Tape muting control pin At muting: “H”
22 LMLOD O Loading motor control pin (loadig direction)
23 LMEJ O Loading motor control pin (eject direction)
24 AMSON O At AMS: “L”
25 N ROUT O Forward/reverse control pin
26 AMSIN I Tape music with/without detection pin “L”: with music
27 PLLSO O PLL data output pin
28 PLLCKO O PLL clock output pin
29 PLLCE O PLL chip enable output pin
30 RDSSI I RDS data input pin
31 AD ON O Power supply control pin for A/D conversion
DOLBY control input/output pin (Fixed at “H” in this set)
32 DOLON I/O At initial mode: valid/invalid selection input of DOLBY function
At normal mode: DOLBY on/off output
METAL control input/output pin
33 MTLON I/O At initial mode: valid/invalid selection input of METAL function
At normal mode: METAL on/off output “H”: on
34 CMON O Capstan motor control pin
35 TAPON O Tape power supply control pin
36 ACCON I Accessory voltage detection pin
37 PLLSI I PLL data input pin
6-1. IC PIN FUNCTION DESCRIPTION
•MAIN BOARD IC501 MN1884820S4G (SYSTEM CONTROLLER)
Pin No. Pin Name I/O Function
SECTION 6
DIAGRAMS

– 17 –
Pin No. Pin Name I/O Function
38 BEEP O Beep sound output pin
39 LCDCKO O LCD clock output pin
40 LCDSO O LCD data output pin
41 LCDINH O LCD brank indication control pin
42 LCDCE O LCD chip enable output pin
43 UNICKO O Clock output pin (for SONY BUS)
44 UNICI I Clock input pin (for SONY BUS)
45 UNISI I Data input pin (for SONY BUS)
46 UNISO O Data output pin (for SONY BUS)
47 VDD – Power supply
48 AVDD – Power supply
49 AVREF+ – A/D reference voltage input pin
50, 51 KEYIN1,KEYIN0 I Key input pin (A/D input)
52 D-BASS I D-BASS switch input pin (A/D input)
53 KEYSEL I Key function setting pin (A/D input)
54 DSTSEL I Destination setting pin (A/D input)
55 RCIN0 I Rotary remote commander input pin (A/D input)
56 VSM1 I FM/AM multi-pass detection pin
57 VSM0 I FM/AM signal meter voltage detection pin (A/D input)
58 AVREF– – A/D reference voltage input pin
59 AVSS – GND
60 GND – GND
61 BUSON O BUS ON control signai output pin (for SONY BUS)
62 SYSRST O System reset signal output pin
63 SEKOUT O SEEK control signal output pin
64 TUNON O Tuner power supply control pin
65 FM ON O FM power supply control pin
66 MUT O System muting control pin At muting: “H”
67 AF SEK O AF seek control signal output pin (Not used)
68 COLOR I Illumination color setting pin “L”: amber, “H”: green (Not used)
69 NOSESW I Front panel removal or attaching detection pin
70 ST IN I/O Stereo detection signal input and forced monaural signal output pin
71 SD IN I Station detection signal input pin
72 REL T I Reel table rotation detection pin
73-76 POS3-POS0 I Tape position detection pin
77 PW SEL I Power select switch input pin
78 TELMUTE I Telephone muting detection pin “L”: 20 dB audio muting
79 TEST I Test mode setting pin
80 ILLIN I ILLIN signal detection pin