Sony TC-TX77 / TC-TX770 Service Manual ▷ View online
– 9 –
Record BIAS Adjustment
Setting:
REC LEVEL control: Standard record position (See page 7)
Set to the TEST mode (REC MEMORY mode). (See page 7)
REC LEVEL control: Standard record position (See page 7)
Set to the TEST mode (REC MEMORY mode). (See page 7)
Procedure:
1. Mode: Record
1. Mode: Record
Record Level Adjustment
Setting:
REC LEVEL control: Standard record position (See page 7)
Set to the TEST mode (REC MEMORY mode). (See page 7)
REC LEVEL control: Standard record position (See page 7)
Set to the TEST mode (REC MEMORY mode). (See page 7)
Procedure:
1. Mode : Record
1. Mode : Record
set
AF OSC
attenuator
600
Ω
10 k
Ω
blank tape
CS-123
CS-123
LINE IN
1) 315 Hz
2) 10 kHz
1) 315 Hz
2) 10 kHz
50 mV (– 23.8 dB)
set
AF OSC
attenuator
600
Ω
10 k
Ω
blank tape
CS-123
CS-123
LINE IN
315 Hz, 50 mV (– 23.8 dB)
315 Hz, 50 mV (– 23.8 dB)
2. Mode: Playback
+
–
–
set
LINE OUT
47 k
Ω
recorded portion
level meter
3. Confirm playback the signal recorded in step 1 become ad-
justment level as follows.
4. If these levels do not adjustment level, adjust the RV152 (L-
CH) and RV252 (R-CH) to repeat step 1 and 2.
Adjustment Level:
Playback output of 10 kHz to playback
output of 315 Hz: ± 0.5 dB.
Adjustment Location: AUDIO board (See page 10)
2. Mode: Playback
+
–
–
set
LINE OUT
47 k
Ω
recorded portion
level meter
3. Confirm playback the signal recorded in step 1 become ad-
justment level as follows.
4. If these levels do not adjustment level, adjust RV153 (L-CH)
and RV253 (R-CH) to repeat step 1 and 2.
Adjustment Level:
– 23.8 ± 0.5 dB (47 to 53 mV)
Adjustment Location: AUDIO board (See page 10)
– 10 –
• Adjustment Parts Location
[AUDIO BOARD] (Component Side)
[SYSTEM CONTROL BOARD] (Component Side)
CN714
CN711
IC304
CN351
RV151
Playback Level (L-CH)
Playback Level (L-CH)
RV251
Playback Level (R-CH)
Playback Level (R-CH)
RV252
Record Bias (R-CH)
Record Bias (R-CH)
RV152
Record Bias (L-CH)
Record Bias (L-CH)
RV153
Record Level (L-CH)
Record Level (L-CH)
IC301
RV253
Record Level (R-CH)
Record Level (R-CH)
CN803
IC803
CN801
TEST Mode
TEST Mode
RV801
Tape Speed
Tape Speed
– 11 –
1
METER-R
I
Digital peak level meter signal input (R-ch)
2
METER-L
I
Digital peak level meter signal input (L-ch)
3
KEY-Y
I
Key input (A/D convert input) *1
4
KEY-X
I
5
FWD-TAB
I
Record proof detection input from S902 (FWD side)
“H”: Not nail
6
CHROM SW
I
Tape type detection input from S903
“L”: Type I
7
RVS-TAB
I
Record proof detection input from S904 (REV side)
“H”: Not nail
8
METAL SW
I
Metal cassette detection input from S906
9
PLAY SW
I
Playback and stop detection input from S907
“L”: Playback
10
TEST MODE
I
Test mode terminal
Normal: “H”
Test mode: “L”
11
POWER OUT
O
Audio and mechanism power on/off output
“L”: Off
12
POWER DET
I
Primary power on/off input
“H”: On
13
CLOSE
O
Loading motor (M901) drive output *2
14
OPEN
O
15
—
—
16
—
—
17
—
—
Not used (Fixed at “L”)
18
—
—
19
—
—
20
—
—
21
CLOCK
O
Clock signal output to back-up memory (IC803)
22
DATA
I/O
Data signal input/output to back-up memory (IC803)
23
RELAY
O
Relay drive output
“L”: On
24
BIAS
O
Control output to recording bias switch (Q352)
“L”: On
25
AU BUS-OUT
O
Audio bus output
26
AU BUS-IN
I
Audio bus input
27
RESET
I
Reset input
28
X CIN
I
Not used (Fixed at “L”)
29
X COUT
O
Not used (Open)
30
X IN
I
Main system clock input (4 MHz)
31
XOUT
O
Main system clock output (4 MHz)
32
Vss
—
Ground
33
REC MUTE
O
Recording mute on/off control output
“L”: Mute on
34
LINE MUTE
O
Line mute on/off control output
“L”: Mute on
35
—
—
Not used (Fixed at “L”)
36
PB MUTE
O
Playback mute on/off control output
“L”: Mute on
37
REC/PB
O
Mode control output to DOLBY NR amplifier (IC301)
When recording: “L”
38
DOLBY B/C
O
DOLBY B/C select signal output
“L”: DOLBY C, “H”: DOLBY B
39
DOLBY ON/OFF
O
DOLBY on/off select signal output
“L”: DOLBY On, “H”: DOLBY Off
40
—
—
Not used (Open)
41
—
—
Not used (Open)
42
—
—
Not used (Open)
43
CD SYNC
O
Control output to CD SYNC LED (D851)
44
P17
O
45
P16
O
Segment signal output to fluorescent indicator tube (FLT851)
46
P15
O
5-1.
IC PIN FUNCTION DESCRIPTION
SYSTEM CONTROL BOARD IC801 M38172M4-150FP (SYSTEM CONTROL)
Pin No.
Pin Name
I/O
Function
SECTION 5
DIAGRAMS
– 12 –
Pin No.
Pin Name
I/O
Function
47
P14
O
48
P13
O
49
P12
O
50
P11
O
51
P10
O
52
P9
O
53
P7
O
Segment signal output to fluorescent indicator tube (FLT851)
54
P6
O
55
P5
O
56
P4
O
57
P3
O
58
P2
O
59
P1
O
60
G5
O
61
G4
O
62
G3
O
Grid Signal output to fluorescent indicator tube (FLT851)
63
G2
O
64
G1
O
65
TYPE 1
O
Tape type output
“H”: Normal position
66
TYPE 2
O
Tape type output
“H”: High position
67
TYPE 4
O
Tape type output
“H”: Metal position
68
—
—
69
—
—
Not used (Fixed at “L”)
70
—
—
71
SOLENOID
O
Plunger (PM901) drive output
“H”: On
72
CAPSTAN
O
Capstan/reel motor (M902) drive output
“H”: On
73
Vcc
—
Power supply (+5 V)
74
Vee
—
Ground
75
AVss
—
Ground for A/D converter
76
Vref
I
Reference voltage (+5 V) for A/D converter
77
HALF
I
Cassette half detection input from S905
78
AMS IN
I
AMS input
79
LIMIT SW
I
Loading detection input from S901
Open: “L”, Close: “M”, COM: “H”
80
PULSE
I
Rotary detection input from PH901
Voltage
Input port
0 V
0.45 V
1.19 V
2.19 V
3.2 V
3.98 V
4.48 V
5.0 V
Pin 4, KEY-X
Open/Close
STOP
PAUSE
FWD
REV
CD
—
Not key input
§
p
P
·
ª
SYNC
Pin 3, KEY-Y
POWER
REW
FF
REC
RESET
DIRECTION DOLBY NR Not key input
ON/OFF
0
)
r
*
1 Key Input
*
2 Loading Motor (M901)
IN
OUT
BRAKE
CLOSE !£
H
L
H
OPEN !¢
L
H
H
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