PDP-4271HD
90
1
2
3
4
1
2
3
4
C
D
F
A
B
E
Is the function corresponding to
selected signal input selected?
Select the corresponding signal
with the input selector.
No
Replace flexible cable.
No
Check the communication between
the CN9003 and CN4013 and
around IC4901.
No
Check the circuit between IC4901 and
IC5301 and replace broken parts.
No
The panel is defective.
No
Check around IC4901 and check the
communications between IC4901
and the microcomputer. If there was
no ploblem replace MAIN Assy.
No
Check around the IC that is found to
have a failure in communication and
the microcomputer. If there was no
ploblem replace MAIN Assy.
No
Replace the MAIN Assy.
Yes
Yes
Image for the PC signal is not
displayed.
⇒
COMP/PC2
Has the signal arrived at IC4901?
(pin 8, 10, 12)
Yes
Is a signal output from IC4901?
(pin 41, 43, 45)
Has the signal arrived at IC5301?
(pin 43, 48, 54)
Yes
Has the symptom been settled
when the MAIN Assy is replaced?
Yes
Yes
Is the communication between
each IC on the MAIN Assy and
the microcomputer nomal?
Yes
15
18
14
13
12
11
10
17
16
13
IC4901 - pin 41 (component_PR)
V: 500 mV/div H: 10
µ
sec/div
13
IC4901 - pin 41 (PC_R)
V: 500 mV/div H: 10
µ
sec/div
15
IC4901 - pin 45 (component_Y)
V: 500 mV/div H: 10
µ
sec/div
15
IC4901 - pin 45 (PC_G)
V: 500 mV/div H: 10
µ
sec/div
17
IC5301 - pin 48 (component)
V: 500 mV/div H: 10
µ
sec/div
17
IC5301 - pin 48 (PC)
V: 500 mV/div H: 20
µ
sec/div
14
IC4901 - pin 43 (component_PB)
V: 500 mV/div H: 10
µ
sec/div
14
IC4901 - pin 43 (PC_B)
V: 500 mV/div H: 10
µ
sec/div
16
IC4901 - pin 43 (component)
V: 500 mV/div H: 10
µ
sec/div
16
IC4901 - pin 43 (PC)
V: 500 mV/div H: 10
µ
sec/div
18
IC5301 - pin 54 (component)
V: 500 mV/div H: 20
µ
sec/div
18
IC5301 - pin 54 (PC)
V: 500 mV/div H: 20
µ
sec/div
11
IC4901 - pin 10 (PC_B)
V: 500 mV/div H: 20
µ
sec/div
12
IC4901 - pin 12 (PC_R)
V: 500 mV/div H: 20
µ
sec/div
Waveforms
Input signal: Color-bar
10
IC4901 - pin 8 (PC_G)
V: 500 mV/div H: 20
µ
sec/div
No video from PC
Flowchart of Failure Analysis for The Video System