Trouble Shooting - Hitachi C47-WD8000 Service Manual

TROUBLE SHOOTING

(1) TROUBLE SHOOTING for POWER CIRCUIT
No raster and no power (How to check LED's Diagnosis)
No
Raster
(Signal Power PWB)
Is Voltage
at D949(K) 5V?
YES
(Signal Power PWB)
Is click sound
of Relay heard?
YES
(Signal Power PWB)
Is Voltage at
of D993（K）
5.8V
YES
(Pow Def PWB)
Has Fuse FP01
blown?
YES
Check
IP01,TP01,
DP05,DP02
etc.
Replace FP01
NO
(Signal Power PWB)
Is Voltage
at pin(6) of PPT3
NO
(R947) 2.5V?
YES
Check
F903,I902,
NO
I941 etc
1.Turn OFF
the power SW.
2.Wait for 3 seconds.
3.Turn ON again after
NO
several seconds, and
observe green LEDs
carefully.
Check
Q980,Q981,
Q901 etc
Check
PDT2 pin(9)
-H out,
PDT3 pin(3)
-DEF 10.5V
etc.
Check
T702, R748,
R730，etc
.
Check
I901,I904,
F902 etc
Check
uCOM
NO
Power control
Check
Q944，
S903
(Pow Def PWB)
(Pow Def PWB)
Are 2 Green LEDs
turned OFF at the
same time?
YES
(Signal Power PWB
Does raster
appear with (7) and (17)
NO
of PPT3 shorted?
YES
(Pow Def PWB)
Is base Voltage
NO
of Q709 normal?
YES
Are Voltages
At both ends of T702
NO
(primary side)
normal?
YES
Check
Q777, QH01,
T701, TH01
etc.
16
NO
)
Find LED(s) that is
Turned dark or OFF
Earlier than the other.
Check
(Pow Def PWB)
DP59
DP48
SW+28/-28V line
SW+115V line
EP40, EP41,
EP45, DP46,
DP40, DP42,etc.
Q777,QH01,
Q701,TH01,
T701 etc.