Troubleshooting - Hitachi 50gx49b Service Manual

TROUBLESHOOTING
1, No Raster and No Power (REPAIR METHOD)
Red LED "ON"?
NO
I
Yes
PROTECT line
D964 (A12V)
Should always
be on A12V)
Check
A12V line
I91 0, Q926,
1001, 1102,
IYOI, IYO2,
I-IMOI etc.
I
PROTECTION
No
Yes
How to check DIAGNOSIS LED's.
I. Turn OFF power SW.
2. Turn ON again after several seconds, and carefully observe 7 green and 1
red LED.
I
D940(+B)
(Change
Brightness, al-
I
Find which LED's is going to dark or OFF.
(Other LED's are going to OFF little bit later same time.)
+ ways on)
Check
+B 120V line
E994, Q777,
+
D939 (TV5V)
(Only 2 turned
on by power)
Check
TV5V line
1913, Q905
D938, L97 1
L114, D116
etc.
+
D946 (TVSV)
(Only 2 turned
on by power)
Check
TVSV line
1912, Q905
D928, L909
L922 etc.
* *
D966 (e27V) D966 (e27V)
Check Check
+27V line +27V line
E995, Q902 E995, Q902
IK04, IK05 IK04, IK05
etc. etc.
D967 (-23V)
D947 (27V)
Check
Check
-23V line
Audio 27V
E996, 1909
line
lK04, IK05
E992, E997
etc.
1401 etc.
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