Pioneer PDP-4270XA Service Manual page 84

1
A
Flowchart of Failure Analysis for The Video System
⇒ ATV
Image for the Terrestrial analog signal
is not displasyed.
Yes
Is the selected input signal a
Terrestrial analog signal?
Yes
B
Has the signal arrived at
IC4701? (pin 57)
Yes
Has the signal arrived at
IC8401? (pin 160)
Yes
Which signal is not output,
main or sub signal?
Main
Is a signal output from
IC4701? (pin 45)
C
Yes
Has the signal arrived at IC5101
(MAIN VDEC)? (pin 148)
Yes
Are the data output from IC5101
(MAIN VDEC)? (pins 86, 87, 94 to
97, 99 to 101, 105 to 107, 110)
Yes
D
Is the communication between
each IC (VDEC, ASIC) on the
MAIN Assy and the microcomputer
normal?
Yes
Replace the MAIN Assy.
Waveforms
Input signal: PAL Color-bar (Analog tuner)
IC4701 - pin 57
1
V: 500 mV/div H: 10 µS/div
E
IC5101 - pin 86, etc.
5
V: 1 V/div H: 2 µS/div
F
84
1
2
No
Select a Terrestrial analog signal?
No
Has the signal arrived at emitter
1
of Q4506?
No
Has the signal arrived at pin 6
2
of Q4508?
Sub
Check around IC4701 and check the
No
communications between IC4701
3
and microcomuputer. If there was
no ploblem, replace the MAIN Assy.
No
Check the circuit between IC4701 and
IC5101 and replace broken parts.
4
Check around IC5101 and check the
No
communications between IC5101
and microcomuputer. If there was
no ploblem, replace the MAIN Assy.
5
Check around the IC that is found to
No
have failure in communication and
the microcomputer. If there was no
ploblem, replace the MAIN Assy.
IC8401 - pin 160
2 3
V: 1 V/div H: 10 µS/div
IC7001 - pin 49
6 7
V: 500 mV/div H: 10 µS/div
2
3
No
Has the signal arrived at C4533?
No
Has the signal arrived at R4508?
No
Is a signal output from
IC4701? (pin 49)
Yes
Has the signal arrived at
IC5103? (pin 1)
Yes
IC4701 - pin 45 IC5101 - pin 148
4
V: 500 mV/div H: 10 µS/div V: 500 mV/div H: 10 µS/div
IC5103 - pin 1
V: 500 mV/div H: 10 µS/div
PDP-427XD
3
4
No
Replace the U4501.
No
Replace the U4501.
6
No
Check the circuit between IC4701 and
7
IC5103 and replace broken parts.
4