Pioneer PDP-4270XA Service Manual page 91

5
B
Has the sound been emitted from
the Headphones?
Waveforms
Input signal: L/R 1 kHz
IC4701 - pin 35 IC4701 - pin 36
42 43
V: 1 V/div H: 400 µS/div V: 1 V/div H: 400 µS/div
IC4701 - pin 31 IC4701 - pin 32
46 47
V: 1 V/div H: 400 µS/div V: 1 V/div H: 400 µS/div
5
6
No
Is sound muting set?
Yes
Is the volume set to 0?
Yes
Is a signal output from IC4701?
(pins 31, 32)
46 47
Yes
Check the FFC between CN8802
and CN4004 or between CN9003
and CN4005.
OK
Is a signal output from IC9001?
(pins 1, 7)
48 49
Yes
Check the cables between CN9001
and CN9202 or between CN9002
and CN9205, or check around the
Headphones jack.
IC4701 - pin 25
44
V: 1 V/div H: 400 µS/div
IC9001 - pin 1
48
V: 1 V/div H: 400 µS/div
6
7
No
Cancel muting, then check again.
No
Raise the volume, then check again.
Check the communications around the IC4701 and between the IC4701
No
and the microcomputer. If there was no ploblem replace the MAIN Assy.
NG
Replace the FFC.
No
Check around the IC9001 and repair the failure points.
NG
Replace the cables.
IC4701 - pin 26
45
V: 1 V/div H: 400 µS/div
IC9001 - pin 7
49
V: 1 V/div H: 400 µS/div
PDP-427XD
7
8
A
B
C
D
E
F
91
8