Sony XR-4750RDS User manual

Model Name Using Similar Mechanism NEW
Tape Transport Mechanism Type MG-25B-136
AEP Model
UK Model
SERVICE MANUAL
XR-4750RDS/C450RDS
SPECIFICATIONS
For RM-X2S (Remote Commander),
please refer to RM-X2S/X3S Service
Manual (9-960-039-S) previously issued.
FM/MW/LW CASSETTE CAR STEREO
Photo: XR-C450RDS
9-925-542-12 Sony Corporation
2001F0500-1 e Vehicle Company
C2001.6 ShinagawaTec Service Manual Production Group
Ver 1.1 2001.06

– 2 –
TABLE OF CONTENTS
1. GENERAL
Location of Controls .......................................................... 3
Setting the Clock ............................................................... 4
Using the Rotary Remote .................................................. 4
Adjusting the Sound Characteristics ................................. 5
Muting the Sound .............................................................. 5
Changing the Sound and Beep Tone.................................. 5
Installation ......................................................................... 6
Connections ....................................................................... 7
2. DISASSEMBLY............................................................ 10
3. ASSEMBLY OF MECHANISM DECK ............. 12
4. MECHANICAL ADJUSTMENTS ......................... 15
5. ELECTRICAL ADJUSTMENTS
Test Mode .......................................................................... 15
Tape Deck Section ............................................................. 15
Tuner Section..................................................................... 16
6. DIAGRAMS
6-1. Printed Wiring Boards – Main Section –.......................... 22
6-2. Schematic Diagram – Main Section – ............................... 25
6-3. Printed Wiring Board – Display Section – ....................... 30
6-4. Schematic Diagram – Display Section – .......................... 32
6-5. IC Pin Function Description .............................................. 35
7. EXPLODED VIEWS .................................................. 37
8. ELECTRICAL PARTS LIST.................................. 40
SERVICING NOTES
Flexible Circuit Board Repairing
•Keep the temperature of the soldering iron around 270 ˚C during
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 –

– 5 –

– 6 –

– 7 –

– 8 –

– 9 –

– 10 –
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

– 11 –
MAIN BOARD, HEAT SINK
1 three screws
(PTT2.6 × 8)
5 screw
(PTT2.6 × 6)
6 mechanism deck
(MG-25B-136)
4 flexible flat cable
(CN301)
1 three screws
(PTT2.6 × 8)
2 sub panel
3 connector
(CN302)
SUB PANEL, MECHANISM DECK (MG-25B-136)
1 screw
(PTT2.6 × 8)
5 heat sink
3 main board
1 two screws
(PTT2.6 × 8)
2 two ground point
screws
4 eight screws
(PTT2.6 × 8)

– 12 –
Note: Follow the assembly procedure in the numerical order given.
2 Install the hanger onto
two claws of the housing.
1 Install the catch to the hanger.
7 Hold the hanger by bending the claw.
A part
B part
C part
D part
8 Hold the hanger by
bending the claw.
3 Put the housing
under A part.
4 Fit claw on B part.
6 Fit projection on D part.
5 Fit projection on C part.
hanger
HOUSING
2 Move the arm (suction) in the arrow
direction and fit on projection.
1 Fit the arm (suction) on the shaft.
projection
ARM (SUCTION)
SECTION 3
ASSEMBLY OF MECHANISM DECK
housing

– 13 –
1 Fit the lever (LDG-A) on
shafts A – C and install it.
shaft A
shaft C
4 type-E stop ring 2.0
shaft A
shaft C
LEVER (LDG-A) / (LDG-B)
GEAR (LDG-FT)
3 Align hole in the gear (LDG-D)
with hole in the lever (LDG-A).
gear (LDG-FB)
hole
gear (LDG-D)
lever (LDG-A)
2 Move the lever (LDG-B)
in the arrow direction.
1 tension spring (lever LDG)
4 gear (LDG-FT)
5 polyethylene washer
hole
shaft B
3 Fit the lever (LDG-B) on
shafts A and C and
install it.
2 Pull the lever in the
arrow direction.

– 14 –
GUIDE (C)
2 guide (C)
1 three claws

– 15 –
TEST MODE
This set have the test mode function. In the test mode, FM Auto
Scan/Stop Level andAM (MW) Auto Scan/Stop Level adjustments
can be performed easier than it in ordinary procedure.
<Set the Test Mode>
1. Set the “power select” switch (S801) is “A” position.
2. Turn ON the regulated power supply. (All LEDs on the set lights
up, and the clock is displayed.)
Note: Press the OFF button, if the clock is not displayed.
3. Push the preset 4 button.
4. Push the preset 5 button.
5. Press the preset 1 button for more than two seconds.
6. Then the display indicates all lights, the test mode is set.
<Release the Test mode>
1. Push the OFF button.
2. Set the power select switch (S801) is “B” position.
•TapeTension Measurement
PRECAUTION
1. Clean the following parts with a denatured-alcohol-moistened
swab: playback head pinch roller
rubber belt capstan
idlers
2. Demagnetize the playback head with a head damagnetizer.
3. Do not use a magnetized screwdriver for the adjustments.
4. After the adjustments, apply suitable locking compound to the
parts adjusted.
5. The adjustments should be performed with the rated power sup-
ply voltage unless otherwise noted.
•Torque Measurement
SECTION 5
ELECTRICAL ADJUSTMENTS
SECTION 4
MECHANICAL ADJUSTMENTS
Mode Torqu Meter Meter Reading
Foward CQ-102C 30 – 65 g•cm
(0.42 – 0.90 oz•inch)
Forward CQ-102C 0.5 – 4.5 g•cm
Back Tension (0.01 – 0.06 oz•inch)
Reverse CQ-102RC 30 – 65 g•cm
(0.42 – 0.90 oz•inch)
Reverse CQ-102RC 0.5 – 4.5 g•cm
Back Tension (0.01 – 0.06 oz•inch)
FF, REW CQ-201B 60 – 200 g•cm
(0.83 – 2.78 oz•inch)
Mode Tension Meter Meter Reading
Forward CQ-403A more than 90 g
(more than 3.18 oz)
Reverse CQ-403R more than 90 g
(more than 3.18 oz)
See the adjustment location from on page 18 for the ad-
justment.
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 18.
set +–
test tape
WS-48A
(3 kHz, 0 dB)
speaker out terminal
4 Ω
speed checker
or
frequency counte
r

– 16 –
TUNER SECTION 0dB=1µV
Cautions during repair
When the tuner unit is defective, replace it by a new one because
its internal block is difficult to repair.
[Note]
Adjust the tuner section in the sequence shown below.
1. FM Auto Scan/Stop Level Adjustment
2. FM Stereo Separation Adjustment
3. FM Noise FocusAdjustment
4. FM Signal Meter Adjustment
5. AM (MW) Auto Scan/Stop Level Adjustment
FM Auto Scan/Stop Level Adjustment
Setting:
SOURCE button: FM
Procedure:
1. Set to the test mode. (See page 15).
2. Push the SOURCE button and set to FM.
Display
FM INTRO
REG
3. Push the preset 3 button.
Display
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
INTRO
REG
FM
INTRO
REG
Adjustment Location: See page 18.
FM Stereo Separation Adjustment
Setting:
SOURCE button: FM
FM RF signal
generator
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%)
0.01 µ F
set
antenna jack (J1)
+
–
speaker out terminal
level meter
4
Ω
Procedure:
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.
L-CH Stereo separation: A-B
R-CH Stereo separation: C-D
The separations of both channels should be equal.
Specification: Separation more than 30 dB
Adjustment Location: See page 18.
FM RF signal
generator
Carrier frequency : 98.0 MHz
Output level : 22 dB (12.6
µ V)
Mode : mono
Modulation : 1 kHz, 22.5 kHz deviation (30%)
0.01 µ F
set
antenna jack (J1)
FM Noise Focus Adjustment
Setting:
SOURCE button: FM
Procedure:
1. Tuner the 98.00 MHz.
2. The then output level is supposing that (A) dB.
3. Adjust with the volume RV3 on TU1 so that the output level is
(A) –32 ± 2 dB then signal generator input set to –20 dB.
Adjustment Location: See page 18.
FM RF signal
generator
Carrier frequency : 98.00 MHz
Output level : 60 dB (1 mV)
Mode : stereo
Modulation : 1 kHz, 75 kHz deviation (100%)
0.01 µ F
set
antenna jack (J1)
+
–
speaker out terminal
level meter
4
Ω

– 17 –
AM (MW) Auto Scan/Stop Level Adjustment
Make this adjustment after “FMAuto Scan/Stop LevelAdjustment”.
Setting:
SOURCE button: MW
AM RF signal
generator
Carrier frequency : 999 kHz
30% amplitude
modulation by
1 kHz signal
Output level : 33 dB
(
44.7
µ
V
)
(50 Ω )set
AM dummy antenna
30 Ω
15 pF
65 pF
antenna jack (J1)
Procedure:
1. Set to the test mode. (See page 15.)
2. Push the SOURCE button and set to MW.
Display
3. Push the preset 3 button.
Display
3 999
MW INTRO
4. Adjust with the volume RV1 on TU1 so that the “MW” indica-
tion 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
Adjustment Location: See page 18.
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 15.)
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
999 @
MW INTRO
3 999
INTRO
INTRO
FM
Specification: Display indication: 158 to 162
Adjustment Location: See page 18.

– 18 –
Adjustment Location:
– SET UPPER VIEW –
Tape Speed
Adjustment
TU1
RV1 AM (MW) Auto Scan/Stop Level Adjustment
RV2 FM Auto Scan/Stop Level Adjustment
RV3 FM Noise Focus Adjustment
RV4 FM Stereo Separation Adjustment
RV1
FM Signal
Meter Adjustment

– 19 –
SECTION 6
DIAGRAMS
• IC Block Diagrams –MAIN Section –
IC1 TB2114F (EL)
VDD
SEEK/RECP
1234567 8 9 10
24 23 22 21 20 19 18 17 16 15
11 12
14 13
BUFFER
XTOUT
O
SC OUT
CE
DIN
CK
DOUT
SR
I/O-1 I/O-2
OUT-1 OUT-2
OUT-3
AM/FM IF VDD FM IN AM IN D-GND
FM CP OUT VT AM CP OUT
VCC RF A-GND XTIN
BUS INTERFACE I/O PORTS OUT PORTS
OSC IN
OR
X'TAL OSC
ON/OFF
REFERENCE
COUNTER
PHASE
COMPARATOR
20BIT
IF COUNTER
2
MODULAS
PRESCALER
12BIT
PROGRAMABLE
COUNTER
AMPAMPAMP
+
–
RIPPLE
FILTER
18BIT
18BIT
22BIT
40BIT
SHIFT
RESISTER
REF
VCC +
–
SIG
SEEK/RECP
4BIT
SWALLOW
COUNTER
PSC
N
DATA
IC3 TDA7330BD-013TR
COSTAS
LOOP
PLL
57kHz
PHASE
DECODER
DIFF
DECODER
CLOCK
RECOVERY
PLL
1.4675kHz
ON/OFF
OSCILLATOR
fx DIVIDER
TEST LOGIC
8th ORDER
SC-BANDPASS
FILTER
2nd ORDER
ANTIALIAS
FILTER
+
–
20 19 18 17 16 15 14 13 12 11
10
986 73 45
12
POR TM FSEL T7 VCC ARI OUAL RODA ROCL T57
MPXIN
VREF
CMP
FILOUT
GND
T1 T3 T4
OSCOUT
OSCIN
VCC

– 20 –
IC151 LC75373ED
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
DECODER LATCH SHIFT
REGISTER CONTROL
–
+
+
–
12 3 45 6 7 8 9 10
20
19
18
17
16
15
14
13
12
11
21
22
2324252627282930313233
34
35
36
37
38
39
40
41
42
43
44
LSELO
L4
L3
L2
L1
VDD
R1
R2
R3
R4
RSELO
RVRIN
RCOM
RT1 RT2 RT3
RTOUT
RSIN
RS1 RS2 RS3
RSOUT
RFIN
RFOUT
RROUT
VSS
CL
DI
CE
VREF
LROUT
LFOUT
LFIN
LSOUT
LS3 LS2 LS1 LSIN LTOUT LT3 LT2 LT1 LCOM LVRIN
IC351 CXA2509AQ-T4
+
–
+
–
+–
+
–
+–
12345 6 7 8 9 10
20
19
18
17
16
15
14
13
12
11
2122232627282930
31
32
33
34
37
38
39
40
2425
PBFB1
PBRIN1
PBREF1
PBFIN1
35
36
PBGND
VCT
PBFIN2
PBREF2
PBRIN2
PBFB2
PBEQ1
PBOUT1
VCC
TAPEIN1
AUXIN1
MSLPF
LINEOUT1
NC NC
G2FB
G1FB
MSTC
DGND
MSOUT
NC
NC
INSW
TAPESW
MSMODE
DRSW
MSSW NC NC LINEOUT2 DIREF AUXIN2 TAPEIN2 PBEQ2 PBOUT2 GND
F2
120µ/70µ
X1
X1
VCT
+
F1
120µ/70µ24dB
F3
LPF
VCC
DETECT
MS ON/
OFF
FWD/RVS
TAPE EQ
TAPE/AUX
NR BIAS
24dB
MS
MODE
T2
T1
1
2
3
4
5
6
7
8OUT2
VS
OUT1
GND
IN1
VCC
IN2
GND
CONTROL CIRCUIT
IC360 MM1322XFBE