Sony XR-1790 User manual

MICROFILM
SERVICE MANUAL
FM/AM CASSETTE CAR STEREO
US Model
Canadian Model
E Model
Model Name Using Similar Mechanism NEW
Tape Transport Mechanism Type MG-36SZ9-32
SPECIFICATIONS
XR-1790
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XR-1790
5-3. SCHEMATIC DIAGRAM – MAIN Section (1/2) – • See page 16 forWaveform.
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XR-1790
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5-4. SCHEMATIC DIAGRAM – MAIN Section (2/2) – • See page 25 for IC Block Diagram.
(Page 24)

XR-1790
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5-5. PRINTED WIRING BOARD – PANEL Section –
• Semiconductor
Location
Ref. No. Location
D4 B-9
D900 C-10
D901 C-7
D902 C-6
D903 C-8
IC900 B-9
5-6. SCHEMATIC DIAGRAM – PANEL Section –
• Waveform
2IC900 #™ (OSC)
2.2 Vp-p
15
µ s
(Page 22)
(Page 17)

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• IC Block Diagram – MAIN Board –
IC450 LC75372E
2
14
36
58
710
9
12
11
14
13
16
15
43
44
41
42
39
40
37
38
35
36
33
34
23
2425
26
19
20
21
22
29
30
31
32 27
28
17
18
DECODER
LATCH CONTROL
SHIFT
REGISTER
ROUT
RFIN
RFOUT
RROUT
RVREF
VREF
LVREF
LROUT
LFOUT
LFIN
LOUT
R2
R1
TEST
VSS
NC
CL
DI
CE
L2
VDD
L1
LT3
LT2
L10dBOUT
LT1
LIN
LCT2
LCT1
L10dBIN
LSELO
L3
NC
RT3
RT2
RT1
RIN R10dBOUT
RCT2 RCT1
R10dBIN
RSELO
NC
R3
+
–
+
–
+
–
+
–
LVREF
LVREF RVREF
LVREF
LVREF
LVREF LVREF
LVREF
LVREF
+
–
+
–
+
–
+
–
+
–
+
–
RVREF
RVREF
RVREF
RVREF RVREF
RVREF
RVREF
+
–
+
–
+
–
+
–

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5-7. IC PIN FUNCTION DESCRIPTION
•MAIN BOARD IC1 LC72322N-9400 (SYSTEM CONTROLLER)
Pin No. Pin Name I/O Function
1 XIN I System clock input terminal (4.5 MHz)
2 TEST2 I Connected to ground
3 NC I Not used (fixed at “H”)
4 AM-SD I AM signal meter voltage detection input from the FM/AM tuner unit (TU100) “H” active
5 FM-SD I FM signal meter voltage detection input from the FM/AM tuner unit (TU100) “H” active
6 STEREO I Stereo detection signal input from the FM/AM tuner unit (TU100) (Commonly used for stereo
display input) FM stereo detection at input of “L”
7 MOTOR O Capstan/reel motor (M901) drive signal output “H”: motor on
8 AMP-MUTE2 O Muting control signal output to the power amplifier (IC500) “L”: muting on
9 MW/SW O MW/SW selection signal output terminal “H”: MW, “L”: SW Not used (fixed at “H”)
10 — O Not used (open)
11 BEEP O Beep sound signal output terminal “H” active
12 POWER-ON O Power on/off control signal output “H”: power on
13 ILL-ON O Power on/off control signal output for the liquid crystal display driver (IC900), illumination lamp
and back light lamp “H”: power on
14 N/R I Tape direction switch (S901) input terminal “H”: forward side, “L”: reverse side
15 TAPE-IN I Tape in detection switch (S903) input terminal “L”: tape in
16 FF-REW I FF/REW detection switch (S902) input terminal “L”: FF/REW mode
17 K1 I Key matrix return signal input terminal Not used (fixed at “L”)
18 K0 I Key matrix return signal input for the frequency select switch (S1)
Used for the E model only
19 AMP-ON O Standby on/off signal output to the power amplifier (IC500) “L”: standby, “H”: amp on
20 SEEK O Seek control signal output to the FM/AM tuner unit (TU100) “H” active
Used for the E model only
21 SEEK O Seek control signal output to the FM/AM tuner unit (TU100) “L” active
Used for the US and Canadian models only
22 LOCAL/DX O Local/DX selection signal output to the FM/AM tuner unit (TU100) “L”: DX, “H”: local
23, 24 — O Not used (open)
25 T2 O Key matrix scan signal output for the frequency select switch (S1)
Used for the E model only
26 T1 O
27 T0 O
28 VOL-CE O Chip enable signal output to the electrical volume (IC450) “H” active
29 VOL-DI O Serial data output to the electrical volume (IC450) “H” active
30 VOL-CL O Serial data transfer clock signal output to the electrical volume (IC450)
31 VDD — Power supply terminal (+5V)
32 MUTE-REQ I Muting request signal input terminal (“H” active) “L”: accessory on, “H”: accessory off
33 BAND-KEY I TUNER switch (S900) input terminal “L” is input when pressing the switch
34 PANEL-IN I Detects the removal of the attaching and removing type front panel block “L”: attaching
Not used (open)
35 NC I Not used (fixed at “L”)
36 to 40 — O Not used (open)
41 MUTE O Audio muting on/off control signal output terminal “H”: muting on Not used (open)
42 — O Not used (open)
43 AMP-MUTE O Amp muting on/off control signal output terminal “L”: muting on Not used (open)
44 ANT-REM O Control signal output for the external power antenna and external amplifier “H” active
Key matrix scan signal output terminal Not used (open)

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Pin No. Pin Name I/O Function
45 to 48 — O Not used (open)
49 KS2 O
50 KS1 O Key matrix scan signal output terminal
51 KS0 O
52 — O Not used (open)
53 LCD-CLK O Serial data transfer clock signal output to the liquid crystal display driver (IC900)
54 LCD-CE O Chip enable signal output to the liquid crystal display driver (IC900) “H” active
55 LCD-DATA O Serial data output to the liquid crystal display driver (IC900) “H” active
56 AM-ON O AM system power supply on/off control signal output terminal “H”: AM on
57 MONO O Not used (open)
58 to 60 — O Not used (open)
61 FM-ON O FM system power supply on/off control signal output terminal “H”: FM on
62 TUNER-ON O Tuner system power supply on/off control signal output terminal “H”: tuner on
Not used (open)
63 MW/LW O MW/LW selection signal output terminal “L”: MW, “H”: LW Not used (open)
64, 65 — O Not used (open)
66 NC I Not used (fixed at “L”)
67 CE I Accessory switch on/off detection signal input terminal
“H”: accessory on, “L”: accessory off (hold mode)
68 RESET I System reset signal input terminal “L”: reset
69 KEY-IN I Key matrix return signal input terminal (A/D input)
70 IFIN I FM and AM intermediate frequency detection signal input from the FM/AM tuner unit (TU100)
71 NC I Not used (fixed at “L”)
72 BU-CHECK I Battery detect signal input terminal
73 VDD — Power supply terminal (+5V)
74 FMIN I FM local oscillator input from the FM/AM tuner unit (TU100)
75 AMIN I AM local oscillator input from the FM/AM tuner unit (TU100)
76 VSS — Ground terminal
77 EO O Main charge-pump control signal output terminal
78 — O Not used (open)
79 TEST1 I Connected to ground
80 XOUT O System clock output terminal (4.5 MHz)