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1
Check 12 : Video circuit OK?
The composite signal and the component from DVD-LSI(IC1501) is output from the HOST I/F(CN1901) via the video
buffer circuit.
A
IC1501
DVD_LSI
Video
COMP
DAC part
B
<Check>
Reproduce DVD-REF-A1 Title 2 Chapters5 (White 1000 IRE)
Monitor the output with the oscilloscope, by setting the COMPO signal to a GNDV1 reference.
Set the Trigger mode to the TV trigger, and the Trigger line to line-150.
Verification location 1
No.
1
C
If the result is not satisfactory, check to see if there are any problems with resin flux cored solder and other
defects in the applicable line, vicinity of major parts stated in the above diagram and peripheral components.
COMPO signal
D
Pedestal Level
< Method of Readjusting Video Levels >
If the video composite output is not within the range of rated value, the video level is readjusted in the following
method.
Turn the video level adjustment volume (VR1671) to adjust its level to 1.0
E
IC1501
LSI
Video
DAC part
F
202
1
2
Q1803 peripheral
Video buffer circuit
Fig.12.1 : Video circuit(Composite)
Rated value
(Sensing pin)
1 000 mVpp
COMPO
Color brust
Horizontal periodic signal
Fig.12.2 : Composite signal white 100 % output waveform
Y
Q1801
Video buffer circuit
Cb
Q1802
Video buffer circuit
Q1804
Cr
Video buffer circuit
Fig.12.3 : Video circuit(Component)
AVH-P7800DVD/UC
2
3
AVCC5
Reference waveform
5 %
Waveform 6
Peak
Rated value
Bottom
0.05 Vpp.
AVCC5
peripheral
peripheral
peripheral
3
4
CN1901
HOST I/F
COMPO
When the result is not satisfactory,
adjust the level to 1.0
0.05 Vpp.
Y
Cb
Cr
4
CN1901
HOST I/F
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