Pioneer AVH-P7800DVD/UC, Service Manual

Page: 202 / 280

AVH-P7800DVD/UC
202
1 2 3 4
1 2 3 4
C
D
F
A
B
E
CN1901
HOST I/F
AVCC5
COMP COMPO
Fig.12.1 : Video circuit(Composite)
Peak
COMPO signal
Bottom
CN1901
AVCC5 HOST I/F
Y Y
Cb
Cb
Cr Cr
Q1803 peripheral
Video buffer circuit
IC1501
DVD_LSI
Q1801
peripheral
Video buffer circuit
IC1501
LSI
Video
DAC part
Q1802
peripheral
Video buffer circuit
Q1804
peripheral
Video buffer circuit
Video
DAC part
Check 12 : Video circuit OK?
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.
<Check>
Fig.12.2 : Composite signal white 100 % output waveform
Fig.12.3 : Video circuit(Component)
< 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 0.05 Vpp.
Pedestal Level
Rated value
Color brust
Horizontal periodic signal
When the result is not satisfactory,
adjust the level to 1.0 0.05 Vpp.
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.
No.
1
Verification location 1
(Sensing pin)
COMPO
Reference waveform
Waveform 6
Rated value
1 000 mVpp 5 %
The composite signal and the component from DVD-LSI(IC1501) is output from the HOST I/F(CN1901) via the video
buffer circuit.