Sony XT-991V, Руководство по обслуживанию

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12
MONITOR SECTION
Equipment Used
The measuring equipment below are used for these electrical
adjustments:
• Oscilloscope
• NTSC pattern generator
• PAL pattern generator
• Regulated DC power supply
• Digital voltmeter
Connection of Equipment
Unless otherwise specified, the measuring equipment should be
connected as shown below:
Setup at Adjustment
1. Press the
[SEL]
button of the wireless remote commander, set
the image quality of the set to “VISUAL STD”.
2. The adjustment signal is a 5-step gray scale signal from a NTSC
pattern generator.
Input the gray scale signal into the tuner unit and connect an
oscilloscope to TP415 on the G board. Check that the width
between the black and white levels of the gray scale signal is
0.74 Vp-w.
Bright Adjustment
Adjustment Procedure:
1. Display the gray scale on the monitor screen.
2. Connect a digital voltmeter to TP (BRIGHT) on the G board.
3. Adjust RV405 so that the reading on the digital voltmeter is
2 V.
Adjustment Location: See page 13.
ACC cord
TV tuner unit
XT-991V
NTSC pattern
generator
MONITOR
OUT jack
INPUT (1)
(VIDEO)
jack
TV monitor
XVM-75V
regulated DC
power supply
(DC 14.4 V)
ACC cord
Connection
cord
parking brake terminal
(Connected to ground)
VIDEO OUT
(75
Ω
)
+
–
white
black
0.74 Vp-p
V COM Amplitude/Bias Adjustment
Adjustment Procedure:
1. Display the gray scale on the monitor screen.
2. Connect an oscilloscope to TP (COM) on the G board.
3. V COM Amplitude Adjustment
Adjust RV401 so that the amplitude of the output waveform is
6.0 V.
4. V COM Bias Adjustment
Adjust RV409 so that the level A of the output waveform is at
4.3 V DC.
Adjustment Location: See page 13.
RGB Amplitude Adjustment
Adjustment Procedure:
1. Display the gray scale on the monitor screen.
2. Connect a oscilloscope to TP (G) on the G board.
3. Adjust RV406 so that the white and the next step of pedestal
are on the same level.
Adjustment Location: See page 13.
γ
0 Adjustment
Adjustment Procedure:
1. Display the gray scale on the monitor screen.
2. Connect an oscilloscope to TP (G) on the G board.
3. Adjust RV407 so that the third step from the bottom becomes
1.2 V.
Adjustment Location: See page 13.
6.0 Vp-p
0 V
A
pedestal
pedestal
white
white
1.2 V
GND