View Full Version : Samsung Flat Screen


Console User
07-31-2014, 09:48 PM
We bought a Samsung 40 Inch Flatscreen about two years ago or so. It's LED so the colors are really really bright. What is the average lifespan of this particular type of TV? Has there been any problems with the Samsung LED TV's?? The only thing I notice on ours is that sometimes the picture is really bright and all the sudden it adjusts and becomes real dark. Also, sometimes when you look real close the brightness & darkness flucuate is this normal??

ChrisW6ATV
08-01-2014, 02:09 AM
Samsung flat-panel TV sets have had some problems with bad electrolytic capacitors, at least some made a few years ago, so that could be a cause of early failure but it would be repairable by someone who wanted to do so, likely. Newer sets like yours may have avoided those bad parts.

The brightness issue is a "feature" called "auto-dimming" or similar. You can turn it off or at least minimize it by looking in the menus for "Eco Solution" or similar, if I remember right, and turning that off. Using modes such as "movie" or "standard" rather than "sports" or "vivid" may also minimize the dimming action.

Jeffhs
08-01-2014, 12:41 PM
My Insignia flat panel also has the auto-dimming feature, referred to in the menu options as adaptive contrast. I turned the auto-dimming off and no longer use it.

My set is coming up on three years old, and I haven't had one bit of trouble with bad capacitors or anything else; the picture is wonderful, as is the sound. The only thing I can fault this set on is the placement of the speakers; they are located below the panel, but they face downward, so they are talking to the top of the TV stand most of the time. One of these days I may get a sound bar or some other kind of external sound system that is front-firing, so I don't have to turn the volume up past 50 percent to hear it. I've tried using my stereo system for the TV audio; it works, and well, but that arrangement doesn't allow muting.

dr.ido
08-01-2014, 12:57 PM
The Samsung LCDs plagued with bad capacitors are a few years older than the LED backlit models.

I'm starting to see the first of these come in with actual faults (cracked panels from accidental damage is far more common).

Most of these have had tab bond failures in the LCD panel itself. Where the failure occurs between the tab and PCB it may be repairable (my attempts so far have failed, but I have seen it done). When the failure is between the tab and the panel the only option is to replace the panel (usually not viable).

Other have had LEDs fail in the backlight. The shows as a dark area in the picture or causes the backlight driver to shutdown. Also repairable, but probably not viable.

LED backlights in general don't seem to last as long a CCFL backlights.

rca2000
08-03-2014, 12:19 AM
THIS is what I was talking about. Those LCD panels that are supposed to last "20 years of constant use". BULLSHIT! !! They are VERY lucky to last FIVE !!

The "tab bond" problem is becomming quite an issue, from what I see. It does not take very long either. A LOT of it is being blamed on the ROHS solder. This may be true. Whatever it is..it is giving flat-panels a not-too-good reputation. And deservedly so.

It s not easy to tell someone with a 46 inch vizio set, only 3-4 years old, but out of warr.."you have a bad panel". They will reply" but I thought these flat sets were supposed to last 20 years"...my old zenith did"..

I recently was able to save a 2010 Sony LCD set from going to the dump. The owner did not want to put much in it. It had a bad standby power chip...AND a bad inverter. I was able to find an inverter on the bay cheap--otherwise--I would have lost the repair. A 4 year old Sony set...

rca2000
08-03-2014, 12:28 AM
The Samsung LCDs plagued with bad capacitors are a few years older than the LED backlit models.

I'm starting to see the first of these come in with actual faults (cracked panels from accidental damage is far more common).

Most of these have had tab bond failures in the LCD panel itself. Where the failure occurs between the tab and PCB it may be repairable (my attempts so far have failed, but I have seen it done). When the failure is between the tab and the panel the only option is to replace the panel (usually not viable).

Other have had LEDs fail in the backlight. The shows as a dark area in the picture or causes the backlight driver to shutdown. Also repairable, but probably not viable.

LED backlights in general don't seem to last as long a CCFL backlights.

Did you really think the LED BL sets would outlast CCFL tubes? I never really did. I DO admit..they LOOK a LOT better--especially those with a modulated-BL, AKA as "dynamic dimming" or Dynamic contrast". BUT--they do NOT seem to hold out real well. Not surprising--when you consider how hot those LED chips have to run. Often--a string of them will be driven with about 100-200 volts, and varied by the dimming ckt. If modulated---there will be from 4-16 separate ckts, driving separate strings all over the panel. These modulator boards do NOT seem to be ultra-reliable, either...

I REALLY do think...that before long..people will be BEGGING to get back to that old, reliable, durable, proven, long-lived , inexpensive display device....the CRT !! With its few faults (heavy, bulky, in particular) it IS the BEST.

dr.ido
08-03-2014, 05:19 AM
The tabs are bonded with some kind of adhesive, so this isn't a ROHS solder issue. A possible repair (I've had about 50-50 success rate with, others claim more) is to wedge something between the tab and the frame (I usually use thermal transfer pads) to keep the affected tab under pressure. You may get a bit more life out of an otherwise bad panel this way, but I don't consider it a real repair.

I have also seen the tab completely removed and reattached with Z-axis tape. The person doing this implied that the tape was incredibly expensive and hard to find, but googling since suggests otherwise - so this maybe viable if you're hands are steady enough to get the alignment right (mine are not).

As for LEDs vs CCFLs I wonder if it's really a fair comparision.

I have laptops that are now 20+ years old. I have a couple of LCD monitors that are now 15 years old. I have a few LCD TVs that are 10-12 years old. All have working CCFL backlights. These all probably have Japanese or Korean panels in them. They almost all cost thousands when new.

Cheapo 2010+ CCFL backlit LCDs are also failing earlier than I would have expected. If a see a certain panel through the vent slots that was used in a lot of $199 special 32" sets sold here I won't even bother opening it anymore. I will either have a bad backlight, bad panel, bad T-CON or a combination thereof. In the unlikely event that it has say a power supply fault it will develop a bad backlight, bad panel, bad T-CON shortly after the repair and come back.

I'm also seeing a lot of dead LEDs in the LED down lights that have been installed everywhere lately due to price drops and "green" incentive schemes. I was in one 3 year old building recently where 8 of the down lights installed in one room had one or more dead LED.

In the various generic LED backlit TVs I've had there is some degree of standardization in the LED driver boards. You can swap parts between different brands/models to some degree. When they do fail it tends to be the a FET rather than the driver IC.

The driver boards in more expensive brand name sets are not interchangable and the IC seems to fail more often. They also seem to shut down with an imbalance error on panels that look fine by eye when driven with a "dumb" generic driver board.

andy
08-03-2014, 10:50 AM
I have also seen the tab completely removed and reattached with Z-axis tape. The person doing this implied that the tape was incredibly expensive and hard to find, but googling since suggests otherwise - so this maybe viable if you're hands are steady enough to get the alignment right (mine are not).

I wasn't aware of that product. I will have to give it a try the next time I run into a problem with a bonded cable. If it sticks strongly enough, alignment shouldn't be a problem using my stereo microscope.

I do see a fair number of bad CCFL tubes in older laptops. So far, none in a TV, but I don't work on many TVs anymore. I would say that see a smaller percentage of bad panels than I did bad CRTs, but the CRTs were usually much older. CRTs usually wear out in a predictable manner, but LCD panels look fine until they fail suddenly. It feels much worse to scrap a big panel that's perfect except for one column of pixels than it does to scrap a CRT with a bad gun.

dr.ido
08-06-2014, 11:25 AM
I guess prior to Pentium 4/Pentium M most laptops became too old/slow/obsolete before their backlights died, whereas anything from 2003 or so onward was still "good enough" to get used by someone until something really broke.

I'm getting sick of working on newer sets myself. The thinner it is the more trouble it is - at least that's how it seems to be with the crap that comes my way. Two more from 2011 consigned to "bad panel" pile tonight - A 50" LG Plasma, and a generic 47" LCD. Time to clear out the backlog of crappy LCDs and work on something else for a while.