Sony XR-1750 User manual

XR-1750
US Model
E Model
Australian Model
SERVICE MANUAL
FM/AM CASSETTE CAR STEREO
SPECIFICATIONS
Model Name Using Similar Mechanism NEW
Tape Transport Mechanism Type MG-52A-135
AUDIO POWER SPECIFICATIONS (US model)
POWER OUTPUT AND TOTAL HARMONIC DISTORTION
13 watts per channel minimum continuous average power into 4 ohms, 4 channels driven from
20 Hz to 20 kHz with no more then 1% total harmonic distortion.
Cassette player section
Tape track 4-track 2-channel stereo
Wow and flutter 0.08% (WRMS)
Frequency response 30 – 20,000 Hz
Signal-to-noise ratio 58 dB
Tuner section
FM
Tuning range US model:
87.5 – 107.9 MHz
E, Australian model:
50 kHz/200 kHz switchable
87.5 – 108.0 MHz (at 50 kHz step)
87.5 – 107.9 MHz (at 200 kHz step)
Antenna terminal External antenna connector
Intermediate frequency 10.7 MHz
Usable sensitivity 8 dBf
Selectivity 75 dB at 400 kHz
Signal-to-noise ratio 65 dB (stereo), 68 dB (mono)
Harmonic distortion at 1 kHz
0.5% (stereo), 0.3% (mono)
Separation 35 dB at 1 kHz
Frequency response 30 – 15,000 Hz
Capture ratio 2 dB
AM
Tuning range US model:
530 – 1,710 kHz
E, Australian model:
9 kHz/10 kHz switchable
531 – 1,602 kHz (at 9 kHz step)
530 – 1,710 kHz (at 10 kHz step)
Antenna terminal External antenna connector
Intermediate frequency 10.71 MHz/450 kHz
Sensitivity 30 µV
Power amplifier section
Outputs Speaker outputs (sure seal connectors)
Speaker impedance 4 – 8 ohms
Maximum power output 35 W ×4 (at 4 ohms)
General
Outputs Power antenna control lead
Power amplifier control lead
Rear line out (1)
Tone controls Bass ±8 dB at 100 Hz
Treble ±8 dB at 10 kHz
Power requirements 12 V DC car battery (negative ground)
Dimensions Approx. 188 ×58 ×182 mm
(71/2 ×23/8 ×71/4in.) (w/h/d)
Mounting dimensions Approx. 182 ×53 ×161 mm
(71/4 ×21/8 ×63/8in.) (w/h/d)
Mass Approx. 1.2 kg (2 lb. 10 oz.)
Supplied accessories Parts for installation and connections (1 set)
Design and specifications are subject to change without notice.
Ver 1.1 2001.04
9-925-564-12 Sony Corporation
2001D0500-1 e Vehicle Company
C2001.4 ShinagawaTec Service Manual Production Group

– 2 –
TABLE OF CONTENTS
1. GENERAL
Location of Controls ........................................................ 3
Installation (US Model) ................................................... 4
Installation (E, Australian Model) ................................... 5
Connection....................................................................... 6
2. DISASSEMBLY.......................................................... 8
3. ASSEMBLY OF MECHANISM DECK ........... 10
4. MECHANICAL ADJUSTMENTS ....................... 16
5. ELECTRICAL ADJUSTMENTS
Tape Deck Section ........................................................... 16
Tuner Section................................................................... 16
6. DIAGRAMS
6-1. IC Pin Function Description ............................................ 18
6-2. Printed Wiring Boards –MAIN Section– ........................ 20
6-3. Schematic Diagram –MAIN Section–............................ 23
6-4. Printed Wiring Board –CONTROL Section– ................. 27
6-5. Schematic Diagram –CONTROL Section–.................... 29
7. EXPLODED VIEWS ................................................ 33
8. ELECTRICAL PARTS LIST................................ 37
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 –

–5 –

–6 –

–7 –

– 8 –
1
Note: Follow the disassembly procedure in the numerical order given.
COVER
SECTION 2
DISASSEMBLY
FRONT PANEL ASS’Y
2
A
2
1
3 Remove the cover
to direction of the arrow A .
1 two claws
1 two claws
1 two claws
2 front panel ass’y

–9 –
MECHANISM DECK
MAIN BOARD, HEAT SINK
5 mechanism deck
3 two screws
(PTT2.6 × 6)
2 flexible flat cable
(CN1)
5 seven screws
(PTT2.6 × 10)
6 heat sink
2 two ground point
screws
3 main board
4 insulator
1 connector
(CN351)
3 three screws
(PTT2.6 × 6)
4 front chassis
1 three screws
(PTT2.6 × 10)

–10 –
SECTION 3
ASSEMBLY OF MECHANISM DECK
Note: Follow the assembly procedure in the numerical order given.
ALIGNMENT OF FRONT SWITCH
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
2 Install the gear (LDG-E).
1 Align hole as shown in the figure.
GEAR (LDGE)

–11 –
CHASSIS (S) ASS’Y
2 screw (PS2 × 4)
1 chassis (S) ass’y
2 screw (PS2 × 4)
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
C
B

–12 –
LEVER (PINCH SELECTION)
1 Align.
2 lever (pich selection)
HEAD PLATE ASS’Y
3 step screw (HP)
3 step screw (HP)
2 Fit shaft in groove.
1 Fit in groove.
groove

–13 –
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
3 Install the spring
(pinch press) to shaft A .
Set the ends of spring to
B and C .
shaft
shaft
B
C
C
B
shaft A
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

–14 –
ARM (SUCTION) 2
Move the arm (suction) in the arrow
direction and fit on projection.
1 Fit the arm (suction) on the shaft.
projection
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)

–15 –
GEAR (LDG-FT)
2 guide (C)
1 three claws
GUIDE (C)
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

– 16 –
FM RF signal
generator
set
digital voltmete
r
SECTION 5
ELECTRICAL ADJUSTMENTS
SECTION 4
MECHANICAL 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
See the adjustment location from on page 17 for the
adjustment.
0 dB=0.775VTAPE DECK SECTION
Speed checker Frequency counter
–1.5 to +2.5% 2,955 to 3,075 Hz
Specification: Constant speed
Adjustment Location: See page 17.
set +–
speed checker
or
frequency counte
r
test tape
WS-48A
(3 kHz, 0 dB) 10 k
Ω
LINE OUT
Tape Speed Adjustment
Procedure:
1. Put the set into the FWD PB mode.
0 dB=0.775VTAPE DECK SECTION
Tape Speed Adjustment
Procedure:
1. Put the set into the FWD PB mode.
TUNER SECTION
FM S Meter Adjustment
Setting:
SOURCE button : FM
FREQUENCY SELECT switch : 9 k (E, Australian model)
0 dB=1 µV
antenna jack (J1)
0.01 µF
TU1 pin !•
Carrier frequency : 97.9 MHz (US model)
: 98.0 MHz (E, Australian model)
Output level : 30 dB (31.6 µV)
Mode : mono
Modulation : 1 kHz, 75 kHz deviation
Procedure:
1. Tune the 97.9 MHz (US model) or 98.0 MHz (E, Australian
model).
2. Adjust RV1 on TU1 so that the digital voltmeter reading is
3.1 V.
Adjustment Location: See page 17.
Mode Torqu Meter Meter Reading
Forward CQ-403A more than 60 g
Reverse CQ-403R (more than 2.12 oz)
•Tape Tension Measurement
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)

– 17 –
Adjustment Location:
–SET UPPER VIEW –
Tape Speed Adjustment
TU1
RV1 FM S Meter Adjustment
22 15 14 1
TU1
Pin !•
–SET SIDE VIEW –

–18 –
6-1. IC PIN FUNCTION DESCRIPTION
•MAIN BOARD IC501 µPD17707GC-522-3B9 (SYSTEM CONTROL)
SECTION 6
DIAGRAMS
1 NIL – Not used (Fixed at “L”)
2, 3 POS3, POS2 I Tape position detection pin
4, 5 POS0, POS1 I Tape position detection pin
6 TAPEON O Tape power supply control pin
7 CM_ON O Capstan motor control pin
8 LM_LOD O Loading motor control pin (loadig direction)
9 LM_EJ O Loading motor control pin (eject direction)
10 TUNON O Tuner power supply control pin
11 FM_ON O FM power supply control pin
12 PW_ON O System power supply control pin
13 MUTE O System muting control pin At muting: “H”
14 VOLCE O Chip enable output pin to electrical volume
15 VOLCKO O Clock output pin to electrical volume
16 VOLSO O Data output pin to electrical volume
17 AMPON O Power amp power supply control pin
18 AMPMUT O Power amp muting control pin At muting: “L”
19 DX_LO O DX/local selection control pin
20 NC1 – Not used
21 GND – GND
22 DSTSEL I Destination setting pin (A/D input)
23 D_BASS I D-BASS switch input pin (A/D input)
24,25 KEYIN1,KEYIN0 I Key input pin (A/D input)
26 RC_IN0 I Rotary remote commander input pin (A/D input)
27 VSM I FM/AM signal meter voltage detection pin (A/D input)
28 AMIFIN I AM(MW,SW) IF input pin
29 FMIFIN I FM IF input pin
30 VDD – Power supply
31 FM_OSC I FM OSC signal input pin
32 AM_OSC I AM OSC signal input pin
33 GND – GND
34 NC2 – Not used
35 EO1 O Main charge-pump output pin
36 TEST0 I Test pin
37 NC3 – Not used
38 SEKOUT O SEEK control signal output pin
39 MW_SW O MW/SW power supply select pin (Not used)
40 BEEP O Beep sound output pin
41 KEYACK O Key acknowledge signal input pin
42 BU_IN I Back up power supply detection pin
METAL control input/output pin
43 MTLSEL I/O At initial mode: auto/manual selection input of METAL function “L”: manual
At manual mode: METAL on/off output “H”: on
At auto mode: input at %ª MTLIN
DOLBY control input/output pin
44 DOLON I/O At initial mode: valid/invalid selection input of DOLBY function
At normal mode: DOLBY on/off output
45 AMSIN I Tape music with/without detection pin “L”: with music
46 ST I/O Stereo detection signal input and forced monaural signal output pin
Pin No. Pin Name I/O Function

–19 –
Pin No. Pin Name I/O Function
47 AMSON O At AMS: “L”
48 N_ROUT O Forward/reverse control pin
49 TAPMUT O Tape muting control pin At muting: “H”
Illumination power supply control pin
50 ILLON O At PW SEL on: ACC on: “H”
At PW SEL off: Power on: “H”
51 SD_IN I Station detection signal input pin
52 NOSESW I Front panel removal or attaching detection pin
53 TELMUT I Telephone muting detection pin “L”: 20dB audio muting
54 REL I Reel table rotation detection pin
55 ACCIN I Accessory voltage detection pin
56 TESTIN I Test mode setting pin
57 RC_IN1 I Rotary remote commander input pin (A/D input)
58 PW_SEL I Power select switch input pin
59 MTLIN I AUTO METAL detection pin “L”: METAL
60 AD_ON O Power supply control pin for A/D conversion
61 KEYSEL I Key function setting pin
62 SEKOUTSEL I Active select pin for #• SEKOUT
63 PULL-OUT I Not used
64 LCDCE O LCD chip enable output pin
65 LCDCKO O LCD clock output pin
66 LCDSO O LCD data output pin
67 LCDINH O LCD brank indication control pin
68 NC6 –Not used (Fixed at “L”)
69 NC7 –Not used
70 NC8 –Not used (Fixed at “L”)
71 NC9 –Not used
72 NC10 –Not used
73 NC11 –Not used
74 VREG O CPU regurator output pin
75 GND –GND
76 X_OUT O System clock output pin (4.5 MHz)
77 X_IN I System clock input pin (4.5 MHz)
78 CE I Fixed at “H”
79 VDD –Power supply
80 RESET I Reset input pin