A while ago I was given a dead Samsung 930B and made an attempt at fixing it by replacing the obviously damaged electrolytic caps. On my first attempt i replaced:
cap# orig uf/v ---> new uf/v
-------------------------------------------------
301 820/25 820/25 nichicon pw
111 820/25 820/25 nichicon pw
112 820/25 820/25 nichicon pw
109 1000/10 1000/25 nichicon pw
110 1000/10 1000/25 nichicon pw
When I pressed the power button the green LED stayed on followed by a high pitched screeching noise coming from everywhere on the board. I replaced the rest of the electrolytics inluding the large one. Here's the rest of the list showing what I replaced:
cap# orig uf/v ---> new uf/v
-------------------------------------------------
113 330/10 330/16 nichicon pw
123 10/50 10/50 nichicon pw
107 47/50 47/50 nichicon pw
105 100/450 100/450 chemicon kxg
345 33/25 33/35 nichicon pw
Now the screeching is gone, it's all nice and quiet. When pressing the power button the LED is green and steady. It appears fine but there's no backlight whatsoever. I can faintly see a 'no input' message moving around the screen when I shine a light at it.
Attached are some pics of the board. After reading other threads in here I've checked my work again and i can't find anything wrong. I've checked the high voltage transformers both primaries read 0K ohm (my $cheap meter only has a R * 1K setting so i can't tell something like 10 ohms from a true short) and the secondaries read 1.3K ohms. There is no continuity between the primaries and secondaries.
I am unable to find any fuses (mentionned in another thread for a 930b) apart from F101 which is good. U202 and U203 look rather suspicious though. I can't read all the numbers on them and am not sure how to test them. Anyone?
cap# orig uf/v ---> new uf/v
-------------------------------------------------
301 820/25 820/25 nichicon pw
111 820/25 820/25 nichicon pw
112 820/25 820/25 nichicon pw
109 1000/10 1000/25 nichicon pw
110 1000/10 1000/25 nichicon pw
When I pressed the power button the green LED stayed on followed by a high pitched screeching noise coming from everywhere on the board. I replaced the rest of the electrolytics inluding the large one. Here's the rest of the list showing what I replaced:
cap# orig uf/v ---> new uf/v
-------------------------------------------------
113 330/10 330/16 nichicon pw
123 10/50 10/50 nichicon pw
107 47/50 47/50 nichicon pw
105 100/450 100/450 chemicon kxg
345 33/25 33/35 nichicon pw
Now the screeching is gone, it's all nice and quiet. When pressing the power button the LED is green and steady. It appears fine but there's no backlight whatsoever. I can faintly see a 'no input' message moving around the screen when I shine a light at it.
Attached are some pics of the board. After reading other threads in here I've checked my work again and i can't find anything wrong. I've checked the high voltage transformers both primaries read 0K ohm (my $cheap meter only has a R * 1K setting so i can't tell something like 10 ohms from a true short) and the secondaries read 1.3K ohms. There is no continuity between the primaries and secondaries.
I am unable to find any fuses (mentionned in another thread for a 930b) apart from F101 which is good. U202 and U203 look rather suspicious though. I can't read all the numbers on them and am not sure how to test them. Anyone?
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