XR-4790, XR-4800, XR-7850 (serv.man2) - Sony Car Audio Service Manual (repair manual). Page 21

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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