Sony XR-4890 User manual

MICROFILM
SERVICE MANUAL US Model
Canadian Model
Model Name Using Similar Mechanism XR-C5100
Tape Transport Mechanism Type MG-25F-136
SPECIFICATIONS
XR-4890
Photo: XR-4890
FM/AM CASSETTE CAR STEREO
– Continued on next page –

– 15 – – 16 –
IC331 TDA7462D
SE3L
SE3R
MUTE
SDA
SCL
PAUSE
OUT FL
OUT FR
OUT RL
OUT RR
SUBOUT+
SUBOUT–
VDD
GND
CREF
SE1L
SE1R
MD+
MD–
CDL+
CDL–
CDR–
CDR+
PDR
PDGND
PDL
SE2L
SE2R
INPUT
GAIN &
AUTO
ZERO
PAUSE
DETECT
INPUT MULTIPLEXER &
MIXING STAGE
REAR SIDE
SELECTOR
FRONT SIDE
SELECTOR
LOUDNESS
CONTROL
CIRCUIT
INPUT
GAIN
BEEP
LOUDNESS
CONTROL
CIRCUIT
SOFT
MUTE
VOLUME
CONTROL
CIRCUIT
COMPANDER
TREBLE/
BASS
CONTROL
CIRCUIT
SUBWOOFER
OUT
FADER
SUBWOOFER
LP
IIC
BUS
DIGITAL CONTROL CIRCUIT
POWER
SUPPLY
FRONT
FADER
FRONT
FADER
REAR
FADER
REAR
FADER
VOICE BANDPASS
HP LP
SDA
SCL
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
+
–
+
–
+
–
+
–
OVER VOLTAGE
PROTECT
REGULATOR
12 3 45 6 7 8 9 10 1211
NC
MODE2 MODE1
STB
VDD
AMP
VCC
ANT
COM
AM
FM
GND
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
TAB
PW-GND
OUT2–
ST-BY
OUT2+
Vcc1
OUT1–
PW-GND1
OUT1+
SVR
IN1 IN2
S-GND
IN4 IN3
AC-GND
OUT3+
PW-GND3
OUT3–
Vcc2
OUT4+
MUTE
OUT4–
PW-GND4
DIAGNOSTICS OUT
IC661 BA3918-V2
IC751 TDA7385
• IC Block Diagrams – MAIN Board –
IC21 TB2118F (EL)
SECTION 6
DIAGRAMS
IC301 CXA2509AQ-T4
VDD
AMP
AMP
AMP
VDD2
12 3 45 6 7 8 9 10
24 23 22 21 20 19 18 17 16 15
11 12
14 13
XO
OSC
CE
DIN
CK
DOUT
SR
I/O-1
I/O-2
OUT-1 OUT-2
VDD2 IFC
VDD FM IN AM IN D-GND FM CP OUT VT AM CP OUT VCC REG
A-GND
XI
SERIAL
INTERFACE
I/O
PORT
OSCILLATOR
ON/OFF
BUFFER
REFERENCE
DIVIDER
PHASE
COMPARATOR
20BIT
IF COUNTER
PRESCALLER
12BIT
PROGRAMMABLE
COUNTER
+
–
REGULATOR
18BIT
18BIT 22BIT
40BIT SHIFT
REGISTER
REF
VCC
SEEK/RECP SEEK/RECP
+
–
SIG
4BIT SWALLOW
COUNTER
OUTPUT
PORT
+
+
+
–
+
–
+–
+
–
+–
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
56
7
8
9
10
VCC
IN2
S-GND
IN1
NC
NC
OUT2
NC
P-GND
OUT1
CONTROL
CIRCUIT
MOTOR
DRIVE
CIRCUIT
BUFFER
BUFFER
IC351 LB1930M-TLM

6-2. SCHEMATIC DIAGRAM — MAIN (1/2) SECTION — • Refer to page 15 for IC Block Diagrams.
– 19 – – 20 –
XR-4890/4900
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.
•C: panel designation.
•U: B+ Line.
• Powervoltageisdc14.4Vandfedwithregulateddcpower
supply from ACC and BATT cords.
• Voltage and waveforms are dc with respect to ground
under no-signal conditions.
no mark : FM
< > :TAPE PLAYBACK
∗: Impossible to measure
• VoltagesaretakenwithaVOM(Inputimpedance10 MΩ).
Voltage variations may be noted due to normal production
tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production
tolerances.
• Circled numbers refer to waveforms.
• Signal path.
F: FM
f: AM (MW)
E:TAPE PLAYBACK
•Waveforms
1
2
IC501 !§ XO
IC501 !™ OSC2
2.8Vp-p
18.432MHz
5.0Vp-p
32.768MHz
(Page 21, 22)

– 21 – – 22 –
XR-4890/4900 6-3. SCHEMATIC DIAGRAM — MAIN (2/2) SECTION —
• Refer to page 15 for IC Block Diagrams.
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.
•C: panel designation.
•U: B+ Line.
• Powervoltageisdc14.4Vandfedwithregulateddcpower
supply from ACC and BATT cords.
• Voltage and waveforms are dc with respect to ground
under no-signal conditions.
no mark : FM
< > :TAPE PLAYBACK
∗: Impossible to measure
• VoltagesaretakenwithaVOM(Inputimpedance10 MΩ).
Voltage variations may be noted due to normal production
tolerances.
• Waveforms are taken with a oscilloscope.
Voltage variations may be noted due to normal production
tolerances.
• Circled numbers refer to waveforms.
• Signal path.
F: FM
f: AM (MW)
E:TAPE PLAYBACK
• Abbreviation
CND : Canadian model.
(Page 19, 20)
(Page 25)

– 25 – – 26 –
6-4. SCHEMATIC DIAGRAM — PANEL SECTION —
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.
•C: panel designation.
•U: B+ Line.
• Powervoltageisdc14.4Vandfedwithregulateddcpower
supply from ACC and BATT cords.
• Voltage and waveforms are dc with respect to ground
under no-signal conditions.
no mark : FM
< > :TAPE PLAYBACK
∗: Impossible to measure
(Page 22)
• VoltagesaretakenwithaVOM(Inputimpedance 10 MΩ).
Voltage variations maybe noteddue to normalproduction tol-
erances.
• Waveforms are taken with a oscilloscope.
Voltage variations maybe noteddue to normalproduction tol-
erances.
• Circled numbers refer to waveforms.
• Signal path.
F: FM
f: AM (MW)
E:TAPE PLAYBACK

– 27 –
6-6. IC PIN FUNCTION DESCRIPTION
• IC501 MASTER U-COM (MN101C12GTA1/MN101C12GTB)
Pin No.
1 AVREF- – Basic voltage (- side) ofAD conversion input
2 VSM I FM/AM common signal meter A/D conversion input terminal
3 KEYIN1 I
4 KEYIN0 I
5 DBAS 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 NCO O Not used
9 RCIN0 I Rotary commander (AD conversion) input
10 AVREF+ I Basic voltage (+side) ofAD conversion input
11 VDD – Power supply
12 OSC OUT –
13 OSC IN –
14 GND – Ground
15 XT IN –
16 XT OUT –
17 GND – Ground
18 RCIN1 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 NCO 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 TESTIN I Test mode setting input terminal
32 RAMBU I Reset detection input of RAM
33 RESET I Reset input terminal
34 VOLMUT O Not used
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 PLLCKD O PLL CLK output terminal
39 PLLCE O PLL CE output terminal
40 PLLSO O PLL DATA output terminal
41 PLLSI I PLL DATA input terminal
42 LCDSD O LCD serial data output
43 LCDCE O LCD chip enable output terminal
44 LCDCKD O LCD serial clock output
45 VOLSO O Electrical volume serial data output
46 NCO O Not used
47 VOLCKO O Electrical volume serial data output
48 ACCIN 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

– 28 –
Pin No. Pin Name I/O Function
50 NCO O Not used
51 AMSON O “L” is output in AMS mode
52 NROUT 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