Sony XR-1780 E Model User manual

MICROFILM
SERVICE MANUAL
FM/MW/SW CASSETTE CAR STEREO
E Model
SPECIFICATIONS
XR-1780
Model Name Using Similar Mechanism XR-1790
Tape Transport Mechanism Type MG-36SZ9-32

– 2 –
TABLE OF CONTENTS
1. GENERAL
Location of Controls ....................................................... 3
Setting the Clock ............................................................. 3
Installation....................................................................... 4
Connections ..................................................................... 6
2. DISASSEMBLY ......................................................... 8
3. MECHANICAL ADJUSTMENTS....................... 12
4. ELECTRICAL ADJUSTMENTS
Tape Deck Section .......................................................... 12
Tuner Section .................................................................. 13
5. DIAGRAMS
5-1. Notes for Printed Wiring Board and
Schematic Diagram ......................................................... 16
5-2. Printed Wiring Board – MAIN Board – ........................ 17
5-3. Schematic Diagram – MAIN Board (1/2) – ................... 19
5-4. Schematic Diagram – MAIN Board (2/2) – ................... 21
5-5. Printed Wiring Board – CONTROL Board – ................ 23
5-6. Schematic Diagram – CONTROL Board – ................... 23
5-7. IC Pin Function Description ........................................... 26
6. EXPLODED VIEWS................................................ 28
7. ELECTRICAL PARTS LIST ............................... 34
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 –
FRONT PANEL ASS’Y
MECHANISM DECK SECTION (MG-36SZ9-32)
Note: Follow the disassembly procedure in the numerical order given.
SECTION 2
DISASSEMBLY
3 top cover
2
1
2
1
4 three claws
5 front panel ass’y
4 two claws
2 two screws
(PTT2.6
× 6)
1 connector
(CN901)
2 two screws
(PTT2.6
× 6)
3 mechanism deck section
(MG-36SZ9-32)

– 9 –
MAIN BOARD, HEAT SINK
BRACKET (MD)
4 five screws
(PTT2.6 × 8)
1 two screws
(PTT2.6 × 6)
5 heat sink
2 two screws
(ground point)
3 MAIN board
1 two screws
(P2.6 × 4)
1 two screws
(P2.6 × 4)
2 bracket (MD
)

– 10 –
MOTOR ASS’Y (CAPSTAN/REEL) (M901)
CASSETTE HANGER (X)
1 two screws
(P2
× 3)
4 motor ass’y (CAPSTAN/REEL
)
(M901)
3 main belt
2 sub belt
1 Remove the claw toward
direction.
2 Remove the return link
toward direction.
5 cassette hanger (x)
3 boss
3 boss
4 two claws
1 Remove the claw toward
direction.

– 11 –
CASSETTE HOLDER (X)
A
1 Push an arrow A part.
2 Removal the cassette holder (x
)
to direction of the arrow.

– 12 –
SECTION 3
MECHANICAL ADJUSTMENTS
Mode Tension Meter Meter Reading
Forward CQ-403A more than 60 g
Reverse CQ-403R (more than 2.12 oz)
•TapeTension Measurement
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 Torque Meter Meter Reading
Forward CQ-102C 25 – 55 g•cm
(0.35 – 0.76 oz•inch)
Forward CQ-102C 1.5 – 4 g•cm
Back Tension (0.02 – 0.06 oz•inch)
Reverse CQ-102RC 25 – 55 g•cm
(0.35 – 0.76 oz•inch)
Reverse CQ-102RC 1.5 – 4 g•cm
Back Tension (0.02 – 0.06 oz•inch)
FF, REW CQ-201B 50 – 150 g•cm
(0.69 – 2.08 oz•inch)
SECTION 4
ELECTRICAL ADJUSTMENTS
TAPE DECK SECTION 0 dB= 0.775 V
1. The adjustments should be performed in the order given in
this service manual.
2. The adjustments should be performed for both L-CH and
R-CH.
TestTape
PB Head Azimuth Adjustment
Procedure:
1. Put the set into the FWD PB mode.
2. Turn the screw and check the output peak value. Adjust the
screw so that the peak value in channels L and R coincides
within 2 dB.
3. Check the phase in the FWD PB mode.
Type Signal Used for
P-4-A063 6.3 kHz, –10 dB head azimuth adjustment
WS-48A 3 kHz, 0 dB tape speed adjustment
screw
position
L-CH
peak
within
2 dB
output
level
L-CH
peak R-CH
peak
within
2 dB
angl
e
R-CH
peak
test tape
P-4-A063
(6.3 kHz, –10 dB)
L-CH
R-CH speaker out terminal
oscilloscope
VH
++
––
Screen pattern
in phase good wrong
45
°
90 °
135 ° 180 °
4 Ω
4 Ω
set
level
meter
test tape
P-4-A063
(6.3 kHz, –10 dB)
set
speaker out termina
l
4 Ω
+
–

– 13 –
4. Repeat the above adjustment for the REV PB mode.
5. Check that output level difference between FWD PB mode
and REV PB mode is within 4 dB.
Adjustment Location: PB head
Tape Speed Adjustment
Setting:
Procedure:
1. Put the set into the FWD PB mode.
2. Adjust adjustment resistor for inside capstan motor so that the
reading on the speed checker or frequency counter becomes in
specification.
Specification: Constant speed
Adjustment Location: See page 15.
See the adjustment location from on page 15 for the
adjustment.
Speed checker Frequency counter
–2 to +3% 2,940 to 3,090 Hz
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.
Note: Adjust the tuner section in the sequence shown below.
1. FM Auto Scan/Stop LevelAdjustment
2. FM Noise Focus Adjustment
3. FM Stereo Separation Adjustment
4. MW Auto Scan/Stop Level Adjustment
FM Auto Scan/Stop Level Adjustment
Setting:
[TUNER] button: FM 1
FREQUENCY SELECT switch: FM50 k
Procedure:
1. Tune the set to 98.0 MHz.
2. Connect the digital voltmeter to TP2 (SD) on MAIN board.
3. Adjust RV2 on TU100 so that the reading on the digital volt-
meter changes point from low to high.
Adjustment Location: See page 15.
FWD
REV





adjustment
screws
+–
speed checker
or
frequency counter
test tape
WS-48A
(3 kHz, 0 dB)
speaker out terminal
set
4
Ω
FM RF signal
generator dummy
antenna
Carrier frequency : 98.0 MHz
Output level : 28 dB (25.1
µ V)
Mode : mono
Modulation : 1 kHz, 22.5 kHz deviation (30%
)
antenna
jack (CN900
)
set
50
Ω
50 Ω
0.1pF
+
–
TP2 (SD)
MAIN board
  
digital
voltmeter

– 14 –
MW Auto Scan/Stop Level Adjustment
Setting:
[TUNER] button: MW
FREQUENCY SELECT switch: MW 9 k
Procedure:
1. Tune the set to 999 kHz
2. Connect the digital voltmeter to TP2 (SD) on MAIN board.
3. Adjust RV1 on TU100 so that the reading on the digital volt-
meter changes point from low to high.
Adjustment Location: See page 15.
FM Noise Focus Adjustment
Setting:
[TUNER] button: FM1
FREQUENCY SELECT switch: FM 50 k
Procedure:
1. Tune the 98.0 MHz.
2. The then output level is supposing that (A) dB.
3. Adjust with the volume RV3 on TU100 so that the output level
is (A) –32 dB then signal generator input set to –20 dB.
Adjustment Location: See page 15.
FM Stereo Separation Adjustment
Setting:
[TUNER] button: FM1
FREQUENCY SELECT switch: FM 50 k
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.
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 TU100
for minimum reading.
R-CH R-CH C
D
L-CH R-CH Adjust RV4 on TU100
for minimum reading.
FM RF signal
generator
Carrier frequency : 98.0 MHz
Output level : 60 dB (1 mV)
Mode : mono
Modulation : 1 kHz, 75 kHz deviation (100%)
0.01 µ F
set
antenna jack (CN900)
+
–
speaker out terminal
level meter
4
Ω
FM RF signal
generator
Carrier frequency : 98.0 MHz
Output level : 76 dB (6.3 mV)
Mode : stereo
Modulation : main: 1 kHz, 33.75 kHz deviation (45%)
sub: 1 kHz, 33.75 kHz deviation (45%)
19 kHz pilot: 7.5 kHz deviation (10%)
0.01 µ F
set
antenna jack (CN900)
+
–
speaker out terminal
level meter
4
Ω
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 (CN900)
+
–
TP2 (SD)
MAIN board
  
digital
voltmeter

– 15 –
Adjustment Location:
Tape Speed Adjustment
RV1 MW Auto Scan/Stop Level Adjustment
TU100
RV2 FM Auto Scan/Stop Level Adjustment
RV3 FM Noise Focus Adjustment
RV4 FM Stereo Separation Adjustment CN901
S1
FREQUENCY
SELECT
SWITCH
10 k (MW)
200 k (FM)
9 k (MW)
50 k (FM)
↔
TP2 (SD)
– SET BOTTOM VIEW –
– SET UPPER VIEW –

– 16 –
SECTION 5
DIAGRAMS
5-1. NOTES FOR PRINTED WIRING BOARD AND SCHEMATIC DIAGRAM
Note on PrintedWiring Board:
•X: parts extracted from the component side.
•Y: parts extracted from the conductor side.
•¢: internal component.
•b:Pattern from the side which enables seeing.
2 Vp-p
222 ns
• Waveform
– MAIN Board –
1IC1 1(XIN)
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics and
tantalums.
• All resistors are in Ωand 1/4W or less unless otherwise specified.
•¢: internal component.
•2: nonflammable resistor.
•C: panel designation.
•U: B+ Line.
• Power voltage is dc 14.4V and fed with regulated dc power supply
from ACC and BATT cords.
• Voltages and waveforms are dc with respect to ground under no-
signal (detuned) conditions.
no mark : FM
( ) : MW/SW
[ ] :TAPE PLAYBACK
• Voltages are taken with aVOM (Input impedance 10 MΩ).
Voltage variations may be noted due to normal production toler-
ances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production toler-
ances.
• Circled numbers refer to waveforms.
• Signal path.
F: FM
f: MW/SW
E:TAPE PLAYBACK

XR-1780
– 17 – – 18 –
5-2. PRINTED WIRING BOARD – MAIN Board –
• Semiconductor
Location
Ref. No. Location
D1 I-4
D2 G-5
D3 F-5
D12 H-2
D100 F-9
D350 H-7
D351 F-9
D503 C-7
D506 D-5
D551 C-6
D600 D-5
D601 D-1
D602 E-1
D603 D-2
D605 D-4
D606 B-4
D607 E-5
D608 D-6
D609 D-2
D610 E-5
D611 D-3
D620 B-5
D621 D-5
D640 C-2
IC1 G-4
IC350 H-8
IC450 G-7
IC500 B-7
Q10 E-2
Q30 H-6
Q31 H-6
Q32 H-6
Q60 E-3
Q100 E-9
Q101 E-9
Q102 E-9
Q103 F-9
Q104 F-8
Q105 F-8
Q106 F-3
Q350 I-7
Q351 I-7
Q553 B-9
Q554 B-9
Q600 E-2
Q601 D-2
Q602 D-2
Q604 E-3
Q605 E-4
Q606 E-4
Q608 E-4
Q610 E-5
Q611 E-5
Q612 E-3
(Page 23)

XR-1780
– 19 – – 20 –
5-3. SCHEMATIC DIAGRAM – MAIN Board (1/2) – • See page 16 for Waveform.

XR-1780
– 21 – – 22 –
5-4. SCHEMATIC DIAGRAM – MAIN Board (2/2) – • See page 25 for IC Block Diagram.
(Page 24)

XR-1780
– 23 – – 24 –
5-5. PRINTED WIRING BOARD – CONTROL Board –
5-6. SCHEMATIC DIAGRAM – CONTROL Board –
• Semiconductor
Location
Ref. No. Location
D4 B-9
D900 C-10
D901 C-7
D902 C-6
D903 C-8
IC900 B-9
• Waveform
2IC900 #™ (OSC)
2.2 Vp-p
15
µ s
(Page 17)
(Page 22)