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– 38 –

37

AM STIN

I

AM stereo detection signal input terminal    Not used (fixed at “L”)

38

SEKOUT

O

Seek control signal output to the FM/AM tuner unit (TU1)

39

MW SW

O

MW selection signal output terminal    Not used (open)

40

BEEP

O

Beep sound output terminal

41

KEYACK

I

Input of acknowledge signal for the key entry    Acknowledge signal is input to accept function
and eject keys in the power off status    On at input of “L”

42

BU IN

I

Battery detect signal input terminal    “H”: battery on

43

MTLSEL

I/O

44

DOLON

I/O

45

AMSIN

I

Whether a music is present or not from CXA2509AQ (IC301) is detected at auto music sensor
“L”: music is present, “H”: music is not present

46

ST

I/O

47

AMS ON

O

Tape auto music sensor control signal output to the CXA2509AQ (IC301)
“L” is output to lower the gain for audio level at FF/REW

48

N/R OUT

O

Forward/reverse direction control signal output to the CXA2509AQ (IC301)
“L: forward direction, “H”: reverse direction

49

TAPMUT

O

Tape muting on/off control signal output to the CXA2509AQ (IC301)    “H”: tape muting on

50

ILLON

O

51

SD IN

I

Station detector detect input from the FM/AM tuner unit (TU1)
Stop level for SEEK, BTM, etc. is determined    SD is present at input of “H”

52

NOSESW

I

Detects the removal of the attaching and removing type front panel block    “L”: attaching

53

TELMUT

I

Telephone muting signal input terminal
At input of “L”, the signal is attenuated by –20 dB    Not used (fixed at “H”)

54

REL T

I

Reel table rotation detect signal input from the take-up and supply reel sensor

55

ACCIN

I

Accessory detect signal input terminal    “L”: accessory on

56

TESTIN

I

Setting terminal for the test mode    “L”: test mode (normally fixed at “H”)

57

RC IN1

I

Rotary remote commander shift key A/D input terminal

58

PW SEL

I

Power select switch (S801) input terminal
“L”: position A (halt mode), “H”: position B (operation mode)

59

MTLIN

I

Input terminal to set whether the auto metal function is present or not
“L”: auto metal function is present (fixed at “H”)

60

KEYACT

O

Power supply on/off control signal output for the A/D conversion

61

KEYSEL

I

Setting terminal for the key (fixed at “H”)

62

SEKOUTSEL

I

Active selection terminal for the SEKOUT (pin #•)

63

COLORSEL

I

Setting terminal for the illumination color    “L”: amber, “H”: green    Not used (fixed at “L”)

64

LCDCE

O

Chip enable output to the liquid crystal display driver (IC901)

Input of FM stereo detection signal from FM/AM tuner unit (TU1), and output of forced
monaural control signal to FM/AM tuner unit (TU1)  (Commonly used for stereo display input
and forced monaural output)
FM stereo detection at input of “L”, forced monaural at output of “L”

Dolby control in/out terminal
At initial mode: valid/invalid selection input of dolby function (“L” input: valid)
At normal mode: dolby on/off control signal output    “H”: dolby on
Not used this function in this set (fixed at “H”)

METAL control in/out terminal
At initial mode: auto/manual mode selection input of METAL function    “L”: manual mode
At manual mode: METAL on/off control signal output    “H”: METAL on
At auto mode: input at MTLIN (pin %ª)
XR-4790: Not used this function in this set (fixed at “H”)
XR-4800: Used for the this function

Power supply on/off control signal output terminal at the illumination and liquid crystal display
driver (IC901)    “H”: power on
At power select switch (S801) on mode: “H” output at the accessory on
At power select switch (S801) off mode: “H” output at the power on

– 39 –

65

LCDCKO

O

Serial data transfer clock signal output to the liquid crystal display driver (IC901)

66

LCDSO

O

Serial data output to the liquid crystal display driver (IC901)

67

LCDINH

O

Blank indicate control signal output to the liquid crystal display driver (IC901)
“L”: no display

68

UNICKI

I

Serial data reading clock signal input terminal for the unilink    Not used (open)

69

UNISO

O

Serial data output terminal for the unilink    Not used (open)

70

UNISI

I

Serial data input terminal for the unilink    Not used (fixed at “L”)

71

UNICKO

O

Serial data transfer clock signal output terminal for the unilink    Not used (open)

72

BUSON

O

Bus on/off control signal output terminal    Not used (pull down)

73

SYSRST

O

Reset signal output terminal    “L”: reset    Not used (pull down)

74

VREG

O

CPU regulator output terminal    Connected to capacitor

75

GND

—

Ground terminal

76

X OUT

O

Main system clock output terminal (4.5 MHz)

77

X IN

I

Main system clock input terminal (4.5 MHz)

78

CE

I

CPU chip enable signal input (fixed at “H”)

79

VDD1

—

Power supply terminal (+5V)

80

RESET

I

System reset signal input from the reset signal generator (IC502) and reset switch (S503)
“L” is input for several 100 msec after power on, then it changes to “H”

*1  loading/tape operation motor control

                           MODE

 TERMINAL

LM LOD (pin 8)

“L”

“H”

“L”

“H”

LM EJ (pin 9)

“L”

“L”

“H”

“H”

STOP

LOADING/

FORWARD

EJECT/

REVERSE

BRAKE

– 40 –

• Items marked “*” are not stocked since they

are seldom required for routine service. Some
delay should be anticipated when ordering
these items.

• The mechanical parts with no reference num-

ber in the exploded views are not supplied.

• Hardware (# mark) list and accessories and

packing materials are given in the last of the
electrical parts list.

NOTE:

• -XX and -X mean standardized parts, so they

may have some difference from the original
one.

• Color Indication of Appearance Parts

Example:
KNOB, BALANCE (WHITE) . . . (RED)

↑

↑

Parts Color Cabinet's Color

Ref. No.

Part No.

Description

Remark

Ref. No.

Part No.

Description

Remark

1

3-009-294-01 PANEL, SUB

2

3-935-003-01 SPRING, TORSION

3

3-932-205-21 DOOR, CASSETTE

4

X-3367-636-1 LOCK ASSY

5

3-016-595-01 INSULATOR

* 6

A-3313-351-A MAIN BOARD, COMPLETE (XR-4800)

* 6

A-3313-360-A MAIN BOARD, COMPLETE (XR-4790)

* 7

3-009-816-01 BRACKET (IC) (ISO)

* 8

A-3309-913-A CONNECTOR BOARD, COMPLETE

* 9

3-010-471-01 HEAT SINK

10

3-935-014-01 CUSHION (U)

11

3-915-923-01 SCREW, GROUND POINT

12

3-012-859-01 CAP (25), RUBBER

13

3-937-650-01 PLATE (C), GROUND

* 14

X-3373-269-1 COVER ASSY (ISO)

15

1-782-093-11 CORD (WITH CONNECTOR) (ISO-S)

(SPEAKER)

16

1-782-092-11 CORD (WITH CONNECTOR) (ISO-P) (POWER)

* 17

3-009-813-01 CHASSIS

F801

1-532-877-11 FUSE (BLADE TYPE) (AUTO FUSE) (10A)

#2

#2

#2

#3

F801

MG-25G-136

#2

#2

#2

#1

Front panel ass'y

– 41 –

51

3-018-930-01 KNOB (D-BASS)

* 52

3-014-857-01 SHEET (LCD) (T)

53

3-010-398-01 BUTTON (RELEASE)

54

3-010-395-01 SPRING (RELEASE)

55

X-3374-696-1 PANEL SUB ASSY

56

3-010-383-01 BUTTON (SOURCE)

57

3-010-384-01 BUTTON (M. O. S)

(

r. OFF. – =0. SEEK AMS. + )+)

58

3-010-386-11 BUTTON (B. M. +/–) (–. SEL. +. ATT. BTM)

59

3-010-387-01 BUTTON (PRESET)

(

6. 1. 2. 3. 4. 5. 6. DSPL)

60

3-010-392-01 BUTTON (L. P) (LCL. –. PRST. +)

* 61

3-010-375-01 SHEET (REFLECTOR)

* 62

3-018-385-01 PLATE (LCD), LIGHT GUIDE

* 63

3-018-386-01 HOLDER (LCD)

64

3-010-382-01 PANEL, FRONT BACK

65

3-015-036-01 CUSHION (BACK PANEL)

LCD901 1-801-966-11 DISPLAY PANEL, LIQUID CRYSTAL

Ref. No.

Part No.

Description

Remark

Ref. No.

Part No.

Description

Remark

LCD901

not supplied
(KEY board)

#5

#5