Hitachi 57F59A - Page 84

83
DP65
BACK TO ADJUSTMENTS
2.23 TROUBLE SHOOTING
2
.
23
-01 TROUBLE SHOOTING for POWER CIRCUIT
No raster and no power (How to check LED’s Diagnosis)
Is click sound
of Relay heard?
Is Green LED
turned OFF after
several seconds?
,F901 I901, I904,
F902 D901.T901
Chec
k
Check
No
Raster
Has Fuse F903
blown?
E947, Q777,
QH01, Q701
I907 .I908
YES
NO
YES YES
NO
Is base Voltage
Of Q709 normal?
Does raster
Appear with (8) and (11)
Of PDT2 shorted?
Are Voltages
At both ends of T702
(primary side)
normal?
PDT2 pin(6)
-H out,
PDT2 pin(10)
SW+10.5V
etc.
T702, R748,
R730
etc.
Q777, QH01,
T701, TH01
etc.
NO
NO
YES
YES
Is Voltage
at pin(6) of PDS2
3V or more?
Check
Check
Check
Check
I902.T902
I906.etc
Check
Q944, S903
R907
Check
Ucom
（
I002
）
etc
YES
Check
Check
Is Voltage
at D949(K) 5V?
E941.E943.E944
D954.D943.D941
Q980, Q981,
etc.
NO
NO
NO
YES
NO
NO
YES
1.Turn OFF
the power SW.
2.Wait for 3 seconds.
3.Turn ON again after
several seconds,and
observe green LED
carefully.
YES
Is +B Voltage
at D945(K) is
about 115V?
(Pow Def PWB)