Pioneer PDP-4271HD Service Manual page 87

5
Flowchart of Failure Analysis for The Video System
No video from composite or S-VIDEO
⇒ COMP/S1
Image for the composite or s-video
signal is not displayed.
Yes
Is the function correspondeing to
selected signal input selected?
Yes
Is the compornent cable is
connect to jack? (Input2, Input4)
Yes
Has the signal arrived at IC4701?
(pin 85, 91, 60)
1
Yes
Which signal is not output,
main or sub signal?
MAIN
Is a signal output from IC4701?
(pin 47, 49)
3 4
Yes
Has the signal arrived at IC5101?
(pin 148, 158)
7 8
Yes
Is the communication between
each IC on the MAIN Assy and the
microcomputer normal?
Yes
Has the symptom been settled
when the MAIN Assy is replaced?
Yes
Replace the MAIN Assy.
Waveforms
Input signal: Color-bar
IC4701 - pin 85, 91, 60
1 2
V: 500 mV/div H: 20 µsec/div
IC4701 - pin 45 (composite)
5 6
V: 500 mV/div H: 20 µsec/div
5
6
No
Select the corresponding signal
with the Input selector.
No
Disconnect component and
confirm again.
No
Check the flexible cable between
CN8802 and CN4004.
Check the flexible cable between
CN8803 and CN4005.
SUB
No
Check around IC4701 and check the
communications between IC4701
and microcomuputer. If there was
no ploblem replace MAIN Assy.
No
Check the circuit between IC4701 and
IC5101 and replace broken parts.
No
Check around the IC that is found to
have failure in communication and
the microcomputer. If there was no
ploblem replace MAIN Assy
No
The panel is defective.
IC4701 - pin 57 IC4701 - pin 47 (s-video)
3
V: 500 mV/div H: 20 µsec/div V: 500 mV/div H: 20 µsec/div
IC7001 - pin 3 (composite) IC5101 - pin 148 (composite)
7
V: 500 mV/div H: 20 µsec/div V: 500 mV/div H: 20 µsec/div
6
7
NG
Replace the TANSHI Assy.
NG
Replace or reconnect flexible cable.
No
Is a signal output from IC4701?
Yes
Has the signal arrived at IC7001?
(pin 3)
IC4701 - pin 49 (composite)
4
V: 500 mV/div H: 20 µsec/div
IC5101 - pin 148 (s-video)
7
V: 500 mV/div H: 20 µsec/div
PDP-4271HD
7
8
5
No
Check the circuit between IC4701 and
IC7001 and replace broken parts.
6
IC4701 - pin 49 (s-video)
4
V: 500 mV/div H: 20 µsec/div
IC5101 - pin 158 (s-video)
8
V: 500 mV/div H: 20 µsec/div
8
A
B
C
D
E
F
87