Troubleshooting Samsung LCD TV - AVS Forum
Forum Jump: 
 
Thread Tools
Old 01-17-2015, 04:58 AM - Thread Starter
Newbie
 
d00jolta's Avatar
 
Join Date: Apr 2010
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 0
Question Troubleshooting Samsung LCD TV

Hi,

My Samsung LCD, LE37A557, has been working fine since 2008 when I got it. Until one day, when suddenly while watching a program, the picture dimmed quite noticeably. I mean, like if I had turned down the brightness setting all the way down. It affects the whole screen uniformly, including the menus.

Doesn't matter what input source I use so it's not a signal problem.

The only way I can get a watchable picture is by cranking the brightness setting up to 100 (it was usually plenty bright around 45). It gets pretty washed-out, even with contrast at maximum. In daylight conditions, even full brightness is not bright enough to watch.

The backlight turns on fine, as I can witness through the rear vents.

First I figured that maybe the backlight CCFLs are dimming due to age, but, it seems like that would be something that would happen gradually and not suddenly. I notice no dark band across the screen, so I figure it's probably not a single dead CCFL.

Noticing a bulging capacitor on the power board, I ordered replacement capacitors and replaced all the ones I could find. No improvement, unfortunately.

Next, I replaced the CCFL inverter board with a spare part I bought online. Made no difference as far as I can tell.

Do you know what part I should looking at next?

I gather that either
  1. Main board could be sending a bad signal
  2. T-con board could be messing up the brightness somehow
  3. LCD Panel has given up
  4. Backlight inverter board or power supply board could be producing too little power to run backlight CCFLs at full brightness (but I more or less eliminated these already, I think)
Can the T-con really affect the brightness? All the errors I can find related to it all look like weird artifacts on screen, of which I have none.

Last edited by d00jolta; 01-17-2015 at 05:02 AM.
d00jolta is offline  
Sponsored Links
Advertisement
 
Old 01-17-2015, 06:34 AM
AVS Addicted Member
 
videobruce's Avatar
 
Join Date: Dec 2002
Location: Buffalo NY
Posts: 15,571
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 370 Post(s)
Liked: 178
Given the age of the set and the replacement cost now, I think it would be wiser just to cut your losses and just replace it. (I know that isn't the answer you were looking for.) I doubt it is the panel. if you knew the power draw before, you could measure it now and compare. That would confirm or deny it's the backlighting.

.
.
Abundant OTA television is what makes this country different from all others. Lets keep it this way. If you like Wi-Fi so much, OTA fits right in. After all, it is wireless.
videobruce is offline  
Old 01-17-2015, 12:59 PM - Thread Starter
Newbie
 
d00jolta's Avatar
 
Join Date: Apr 2010
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 0
Quote:
Originally Posted by videobruce View Post
Given the age of the set and the replacement cost now, I think it would be wiser just to cut your losses and just replace it. (I know that isn't the answer you were looking for.)
Well, as I'm an inquisitive and technically inclined person who enjoys troubleshooting, buying a new TV is certainly on the table but so far I've only sunk about 30$ into the project. I'm still willing to experiment a bit more, especially since I do have watchable picture (it's just a bit lo-fi).

Quote:
Originally Posted by videobruce View Post
I doubt it is the panel. if you knew the power draw before, you could measure it now and compare. That would confirm or deny it's the backlighting.
That's a good point, thanks for the tip! Unfortunately, I don't have a power meter and didn't measure before either. =(
d00jolta is offline  
Old 01-17-2015, 02:48 PM
AVS Addicted Member
 
videobruce's Avatar
 
Join Date: Dec 2002
Location: Buffalo NY
Posts: 15,571
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 370 Post(s)
Liked: 178
Have you obtained a service manual??

Is this a TV for the N. American market??;
https://www.avforums.com/threads/sam...ntrast.733590/

.

.
.
Abundant OTA television is what makes this country different from all others. Lets keep it this way. If you like Wi-Fi so much, OTA fits right in. After all, it is wireless.

Last edited by videobruce; 01-17-2015 at 02:54 PM.
videobruce is offline  
Old 01-18-2015, 08:07 AM - Thread Starter
Newbie
 
d00jolta's Avatar
 
Join Date: Apr 2010
Posts: 3
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 0
Quote:
Originally Posted by videobruce View Post
Have you obtained a service manual??

Is this a TV for the N. American market??;

.
No, couldn't find a service manual. Any clue on where to look? Samsung doesn't provide one online, it seems.

I'm in Northern Europe so it's not an American model.

Thanks for the thread link. It's a bit of a dredge trying to find any useful info in it though. =)
d00jolta is offline  
Old 01-18-2015, 11:32 AM
AVS Addicted Member
 
videobruce's Avatar
 
Join Date: Dec 2002
Location: Buffalo NY
Posts: 15,571
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 370 Post(s)
Liked: 178
You really should have your country listed at least for your location. Since that is a European model, search for sites there. Usually it's easy to get a Samsung manual, especially a older one, though that may not of been a popular model.

.
.
Abundant OTA television is what makes this country different from all others. Lets keep it this way. If you like Wi-Fi so much, OTA fits right in. After all, it is wireless.
videobruce is offline  
 

Tags
repair , Samsung , troubleshooting
Thread Tools


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off