Pioneer PRO-141FD Service Manual page 59

5
[6] VIDEO SYSTEM
Flowchart of Failure Analysis for The Video System
=> CVBS (INPUT 1)
A composite input signal is not
displayed.
Yes
Is INPUT 1 selected with the
Input Selector?
Yes
Is a signal input to Pin 7 of IC4701
(RGB SW)? (pin 7)
1
Yes
Has the signal arrived at IC4801?
(VDEC) (pin 22 or TP4801)
2
Yes
Is a signal output from IC4801?
(VDEC) (pins 93 to 97, 99 to 104,
107 to 109)
3
Yes
Replace the MAIN Assy.
Waveforms
Input signal: NTSC Color-bar (RCA termial)
IC4701 - pin 7 (Y)
1 2
V: 500 mV/div H: 10 μsec/div
5
6
• Check if the unit is in Energy Save mode.
• Check if the unit is in Video OFF mode.
No
Select INPUT 1.
No
Failure in parts located between the JA4601 input terminal and Pin 7 of IC4701,
breakage in the signal lines, or poor connection of JA4601
No
Failure in IC4701 or C4805,
or breakage in the signal lines
No
Failure in IC4801
IC4801 - pin 22 or TP4801 (CVBS) IC4801 - pins 93,etc. (OUT)
3
V: 500 mV/div H: 10 μsec/div V: 1 V/div H: 2 μsec/div
PRO-141FD
6
7
Yes
7
8
A
B
C
D
E
F
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