Pioneer PDP-4280HD Service Manual page 58

1
A
=> PC
Image for the PC signal is not
displayed.
Yes
Is the function corresponding to
selected signal input selected?
Yes
B
Has the signal arrived at IC4701?
(pins 30, 32, 34)
10 11
Yes
Is a signal output from IC4701?
(pin 41, 43, 45)
13 14
Yes
Has the signal arrived at IC5001?
(pin 43, 48, 54)
16 17
Yes
C
Is the communication between
each IC on the MAIN Assy and
the microcomputer nomal?
Yes
Has the symptom been settled
when the MAIN Assy is replaced?
Yes
Replace the MAIN Assy.
D
Waveforms
Input signal: Color-bar
IC4701 - pin 64 (PC_G)
10
V: 500 mV/div H: 20 μsec/div
IC4701 - pin 66 (PC_B)
11
V: 500 mV/div H: 20 μsec/div
E
IC4701 - pin 68 (PC_R)
12
V: 500 mV/div H: 20 μsec/div
F
58
1
2
No
Select the corresponding signal
with the input selector.
No
Check the communication between
the CN4701 and around IC4901.
12
No
Check around IC4701 and check the
communications between IC4701
15
and the microcomputer. If there was
no ploblem replace IC4701.
No
Check the circuit between IC4701 and
IC5001 and replace broken parts.
18
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
The panel is defective.
IC4701 - pin 30 (component_PR)
13 13
V: 500 mV/div H: 10 μsec/div
IC4701 - pin 34 (component_Y)
15 15
V: 500 mV/div H: 10 μsec/div
IC5001 - pin 48 (component)
17 17
V: 500 mV/div H: 10 μsec/div
2
3
IC4701 - pin 30 (PC_R) IC4701 - pin 32 (component_Pb)
14
V: 500 mV/div H: 10 μsec/div V: 500 mV/div H: 10 μsec/div
IC4701 - pin 34 (PC_G) IC5001 - pin 43 (component)
16
V: 500 mV/div H: 10 μsec/div V: 500 mV/div H: 10 μsec/div
IC5001 - pin 48 (PC) IC5001 - pin 54 (component)
18
V: 500 mV/div H: 20 μsec/div V: 500 mV/div H: 20 μsec/div
PDP-4280HD
3
4
IC4701 - pin 32 (PC_B)
14
V: 500 mV/div H: 10 μsec/div
IC5001 - pin 43 (PC)
16
V: 500 mV/div H: 10 μsec/div
IC5001 - pin 54 (PC)
18
V: 500 mV/div H: 20 μsec/div
4