Sony XR-4890 Service Manual ▷ View online
– 25 –
– 26 –
XR-4890
6-4. PRINTED WIRING BOARD — PANEL SECTION —
Note:
• X
: parts extracted from the component side.
•
¢
: internal component.
• b
: Pattern from the side which enables seeing.
• Abbreviation
CND : Canadian model.
(Page 19)
Ref. No.
Location
• Semiconductor
Location
IC901
A-8
Ref. No.
Location
• Semiconductor
Location
D902
B-12
D903
B-12
D904
B-11
D951
C-9
Q941
B-1
Q942
C-1
Q943
C-1
Q944
C-1
Q945
C-2
– 27 –
– 28 –
6-5. SCHEMATIC DIAGRAM — PANEL SECTION —
Note on Schematic Diagram:
• All capacitors are in µF unless otherwise noted. pF: µµF
• All capacitors are in µF unless otherwise noted. pF: µµF
50 WV or less are not indicated except for electrolytics
and tantalums.
and tantalums.
• All resistors are in
Ω
and
1
/
4
W or less unless otherwise
specified.
•
¢
: internal component.
•
C
: panel designation.
•
U
: B+ Line.
XR-4890
(Page 23)
• Power voltage is dc 14.4V and fed with regulated dc power
supply from ACC and BATT cords.
• Voltage and waveforms are dc with respect to ground
under no-signal conditions.
no mark : FM
<
no mark : FM
<
> : TAPE PLAYBACK
∗
: Impossible to measure
• Voltages are taken with a VOM (Input impedance 10 M
Ω
).
Voltage variations may be noted due to normal production tol-
erances.
erances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production tol-
erances.
erances.
• Circled numbers refer to waveforms.
• Signal path.
• Signal path.
F
: FM
f
: AM (MW)
E
: TAPE PLAYBACK
• Abbreviation
CND : Canadian model.
– 29 –
6-6. IC PIN FUNCTION DESCRIPTION
• IC501 MASTER U-COM (MN101C12GTC1)
Pin No.
1
VREF-
–
Basic voltage (- side) of AD conversion input
2
VSM
I
FM/AM common signal meter A/D conversion input terminal
3
KEYIN1
I
4
KEYIN0
I
5
DBASS IN
I
Position detecting AD input terminal of D-BASS
6
DSTSEL
I
Terminal for setting to select the value of destination
7
FUNC-SEL
I
Function selecting (AD conversion) input
8
–
O
Not used
9
RC-IN0
I
Rotary commander (AD conversion) input
10
VREF+
I
Basic voltage (+side) of AD conversion input
11
VDD
–
Power supply
12
OSC2
–
13
OSC1
–
14
VSS
–
Ground
15
XI
–
16
XO
–
17
MMOD GND
–
Ground
18
RC-IN1
I
Rotary commander shift input
19
SYSRST
O
SYSTEM RESET control output
20
BUSON
O
BUS ON control output
21
UNISO
O
Serial data output
22
UNISI
I
Serial data input
23
UNICKO
O
Serial clock output
24
UNICKI
I
Serial clock input
25
–
O
Not used
26
KEYACK
I
Key input acknowledge
27
NOSESW
I
Removing/attaching front panel detection input
28
BU-IN
I
BACK-UP detection input terminal
29
SIRCS
I
Remote control input
30
TELMUT
I
TELEPHONE MUTE detection input
31
TEST-IN
I
Test mode setting input terminal
32
RAMBU
I
Reset detection input of RAM
33
RESET
Reset input terminal
34
VOL-MUT
O
Electrical volume mute control output
35
BEEP
O
Control output for buzzer
36
AMPMUT
O
Power amplifier mute control output terminal
37
AMPON
O
Power amplifier STANDBY control terminal
38
PLL-CKD
O
PLL CLK output terminal
39
PLL-CE
O
PLL CE output terminal
40
PLL-SO
O
PLL DATA output terminal
41
PLL-SI
I
PLL DATA input terminal
42
LCD-SO
O
LCD serial data output
43
LCD-CE
O
LCD chip enable output terminal
44
LCD-CKO
O
LCD serial clock output
45
VOL-SIO
O
Electrical volume serial data output
46
–
O
Not used
47
VOL-CKD
O
Electrical volume serial data output
48
ACC-IN
I
Accessory power supply detection input
49
MUT
O
System MUTE control output
Pin Name
I/O
Function
KEY (AD conversion) input
Radiator (18.432 MHz) connecting terminal
Sub clock (for clock) radiator (32 kHz) connecting terminal
– 30 –
Pin No.
Pin Name
I/O
Function
50
NCO
O
Not used
51
AMSON
O
“L” is output in AMS mode
52
N/R-OUT
O
FOR/REV control output
53
MTLON
I/O
Metal control input/output
54
TAPMUT
O
Tape mute control output
55
DOLON
I/O
Dolby control input/output
56
AMSIN
I
Input to detect existence of song during AMS mode
57 to 75
NCO
O
Not used
76
ST
I/O
Combination stereo input and monaural output
77
SD-IN
I
SIGNAL DETECTOR input terminal
78
REIN 1
I
79
REIN 0
I
80
AD ON
O
Power supply control output of AD conversion
81
PW SEL
I
Power selection initialise
82
ILLON
O
Illumination power supply control output
83
REL
I
Input to detect rotation of reel table
84
POS3
I
85
POS2
I
86
POS0
I
87
POS1
I
88
LM LOD
O
Loading motor control output (to a direction of loading)
89
LM EJ
O
Loading motor control output (to a direction of ejection)
TAPE power supply control output
When ‘on’ is output, “H” is output, otherwise when ‘off’ is output, “L” is output.
91
CM ON
O
Capstan motor control signal output terminal of TAPE
92
PW ON
O
System power supply control output
93
FM ON
O
FM power supply control output terminal
94
TUNON
O
TUNER power supply control output terminal
95
DAVSS
Ground
96 to 99
NCO
O
Not used
100
DAVDD
Not used (Power supply for DA converter)
Tape position signal detection input
Rotary encoder input terminal
90
TAPON
O
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