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