Osc.
Display
Control
A-D Converter
Auto-Tuning
Control
Det
IC300
Chroma
Circuit
IC700
VR600
Volume
Control
8 Q800~Q802, Q804~Q806
Display
Voltage
Generator
4 IC600Speaker
Audio
Amp.
Common
Driver
LCD
Segment
Driver
1 — Color Tuner: TU200 TEPU5-02
Selects a desired radio wave and changes it to the video IF signal.
2 — Video IF Amp.: Q200 2SC4238
Amplifies the video IF signal output from the tuner TU by 10 times (20 dB).
3 — Video Det./Sound Det./FM Det./AFT/AGC: IC200 M51348FP
Eliminates the carrier wave in the video IF signal, and picks up the video signal and the sound IF signal.
Also, the sound signal is picked up from the sound IF signal by FM detection.
4 — Audio Amp.: IC600 NJM2070M
Sound amplification.
5 — Chroma Circuit: IC300 M52042FP
Generates the tricolor (red, green, and blue) from the video signal.
Converts the color signal into a digital signal.
Also, generates the clock pulse for the display and controls the display.
7 — Tuning Voltage Generator: IC500 MSC1169MS-K
Generates the tuning voltage with the tuning pulse (TU) output from 6.
8 — Display Voltage Generator: Q800~Q802, Q804~Q806, 2SD601A-R x 4, 2SB709A-R, 2SD1149-S
Generates the display voltages V0 ~ V4 with VEE1 and VCC7 outputs from the power supply.
— 2 —
CIRCUIT DESCRIPTION
TUNING VOLTAGE GENERATOR
BT
BS
16
15
BS
Vcc
VCC6
IC500 MSC1169MS-K
14
BT
13
IN
12
OUT
11
TU
10
H/L
TU
H/L
BU
9
U/V
VREFU1U2
1
2
VL1
VL2
VH1
VH2
GND
3
4
5
6
7
8
VREF
R500R501R502
GND
Figure 1
This circuit generates the DC tuning voltage BT for selecting a channel with a TU pulse being output from
IC700.
IC500 has 3 circuits for converting pulses to voltages; it selects one of VHF-L, VHF-H, or UHF, and
causes the tuning voltage to be output from the OUT terminal (pin 12). Figure 2 and Table 1 show the
conditions for selection.
IC500
TU
11
VHF
-L
VHF
-H
UHF
910
U/V H/L
Figure 2
12
OUT(BT)
— 3 —
Inputs
U/V
L
L
H
H
H/L
L
VHF-L receiving
H
VHF-H receiving
L
UHF receiving
H
UHF receiving
Table 1
Function
POWER SUPPLY
Vref
VCC1-1
C100
D100
C105
CP100
VR100
R101
C135
Q100
Q101
R111
R102
C140
Q111
R115
C145
R117
Figure 3
1
9
CP104
T100
GND
VCC2-2
L102
D155
32
4
5
D152
6
7
D150
D152
C112
L101
C110
C113
VCC2-3
R133
VCC7
CP108
VCC6
CP107
VCC2
CP109
VEE1
CP110
C115
C114
The power supply consists of a DC-DC converter and causes the voltages to be output as shown in Table 2.
NameVoltageFunction
VCC23.95 ± 0.02 VMain voltage
VCC630.5 ~ 39.0 VTuning voltage
VCC753.5 ~ 72.5 VTuning voltage/Display voltage
VEE1–6.3 ~ –7.9 VDisplay voltage
Table 2
— 4 —
ADJUSTMENT
LINEAR PCB
Items To Be Adjusted
ItemMeasuring Instrument
VCC2 voltage settingVoltmeter
Video detection coil adjustmentTV signal generator, pattern generator, oscilloscope,
low-pass filter
AFT coil adjustmentSweep generator, oscilloscope, voltmeter
Contrast adjustmentTV signal generator, pattern generator, oscilloscope
AGC adjustmentTV signal generator, pattern generator, IF levelmeter
Adjustment And Test Point Locations
T201
T200
Top View
— 5 —
TP7
VR100
TP5
VR300
TP2
TP1
PadIF
VR200
TP3
Bottom View
Equipment Connection / Adjustment Procedure
VCC2 Voltage Setting
TV-600
Set
TP4
Voltmeter
Output
TP1
InputInputInputOutputOutput
Connection PointSignalConnectionPoint
AdjustResult
VR100
Voltmeter
— 6 —
TP1
Adjust for 3.95 ± 0.02 V
reading on voltmeter.
* Desolder the IF pad to open.
Pattern
generator
Signal
generator
Video Detection Coil Adjustment
TV-600
Set
InputOutput
TP2
TP3
Oscilloscope
Low-pass
filter
InputInputInputOutputOutput
Connection PointSignalConnectionPoint
AdjustResult
Pattern
generator
Signal
generator
TP2T200TP3
Color bar
45.75 MHz
40 ± 3 dBµ
Low-pass filter
Oscilloscope
AFT Coil Adjustment
* Desolder the IF pad to open.
Sweep
generator
Input
TP2
TV-600
Set
OscilloscopeVoltmeter
Output
TP4
45.75±5 MHz
Sweep
generator
(Sweep) Marker:
TP2T201TP4
45.75 MHz
Voltmeter
Oscilloscope
70 ± 3 dBµ
Adjust for DC level at mini-
Adjust for 2.0 ± 0.2 V reading
on voltmeter.
Confirm that the marker is at
the middle of S-curve on oscilloscope.
* Desolder the IF pad to open.
Pattern
generator
Pattern
generator
Signal
TP2VR300TP5
Color bar
45.75 MHz
70 ± 3 dBµ
generator
Contrast Adjustment
Signal
generator
InputOutput
Oscilloscope
— 7 —
TP2
TV-600
SetOscilloscope
TP5
Adjust step form wave to read
0.8 ± 0.05 Vp-p.
* Short the IF pads.
AGC Adjustment
Pattern
generator
Signal
generator
TV-600
Set
InputOutput
TP7
TP2
InputInputInputOutputOutput
Connection PointSignalConnectionPoint
AdjustResult
Pattern
generator
TV signal
TP7VR200 IF levelmeterTP2
Color bar
65 ± 5 dBµ
generator
IF levelmeter
Adjust for 84 ± 2 dBµ
reading on the IF levelmeter
— 8 —
A/D PCB
Item to Be Adjusted
ItemMeasuring Instrument
Clock adjustmentVoltmeter
Adjustment And Test Point Locations
TOP VIEW
TP6
VR700
Equipment Connection / Procedure
Clock Adjustment
TV-600
Set
Output
TP6
InputInputInputOutputOutput
Connection PointSignalConnectionPointAdjustResult
VR700
Voltmeter
Voltmeter
TP6
Adjust for 2.05 ± 0.05 V reading on voltmeter.
— 9 —
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