http://www.youtube.com/watch?v=ZVVUUAz78cI
Here is the sequence of events when I turn on the set:
-press power button, hear click, see blinking red LED
-after a couple of seconds, I see a faint glow from the set, i.e. it changes from black to a dark gray, so I think the backlight is on.
-at the same time the glow starts I hear a faint buzzing/crackling sound -- it sounds like very quiet electrical arcing (but I don't smell anything)
-a second or so after the buzzing starts, the video comes on very briefly -- less than a second, and then goes black. At that point, the buzzing stops, but the audio from the programming continues.
Have tried a total set reset with no change (not sure I did it correctly -- pressed remote control "exit" for 12 seconds, then down arrow, then enter ???) Have also tried unplugging for several hours with no change.
Is this enough info to make a definitive diagnosis of the problem? Maybe the power supply board? Or do I need to gather more info.
Thanks.
Reply 1 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Does anyone have an opinion about whether I should replace the other similar capacitors on the board? There are two more of the same type that are not oozing, but I'm thinking if there is a whole batch of bad capacitors, then I may as well replace all five while I'm in there with the soldering iron...
Reply 2 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
-They are branded "Samwha", which apparently is a company that took over Samsung capacitor manufacturing in 2002.
-The failed capacitors are series "WB". The current Samwha website indicates that this series was "obsoleted in 1999" (http://www.samwha.com/electric/templatedirs/guest/pro_discon23.html)
Exactly what "obsoleted in 1999" means isn't clear, but it seems strange that they were used on a TV manufactured in 2007. I found a datasheet for the series here: http://www.abcd-e.cn/abcd-e/www/a/products/capacitors/aluminum_electrolytic_capacitors/samwha/samwha_2006/wb.pdf They are described as "ultra low impedance" and have a high ripple current tolerance. The Samwha website identifies the "MK" series as their current replacement for "WB". http://www.samwha.com/electric/templatedirs/guest/product23.html
I found an almost exact specification match with the Nippon Chemi-Con KZE series http://www.chemi-con.com/files/KZE.pdf , specifically EKZE100ELL102MJ16S. I ended up ordering this instead of the KY series I linked to in my previous post.
I have since read on many posts that people have been successfully picking up off-the-shelf capacitors at Radio Shack or Fry's that are slightly over-rated, i.e. 1000uF, 16V capacitors apparently provide some additional ripple-current capacity than the 10V equivalent. Not being an electrical engineer, I'm not sure if there are any downsides to that approach, but fyi I had a look in Fry's this morning and they stock a 1000uF, 16V "ITE" capacitor for $1.92 which works out to almost the same total cost as I'm paying for 5 capacitors plus shipping from "mouser.com" (I decided to use Mouser instead of Digikey when I realized Mouser's Dallas-area distribution center is about 30 miles away, so UPS is next day for me).
Reply 3 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Reply 4 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
After re-installing the power supply board in the TV, YEA!, it works again!
Samsung, if you are reading this, you really ought to initiate some kind of goodwill extended warranty program for these capacitor failures. After several days of Googling, it is apparent that this problem affects thousands of owners of many different models of Samsung TV. Clearly, this is a manufacturing defect. The fact that it doesn't typically reveal itself until after 1 year doesn't change the fact that the defect existed at the time of manufacture. As a minimum, an appropriate response would be to offer remanufactured power supply boards as a free exchange for ones with bulging capacitors. It would also be helpful to issue service bulletins that describe the problem and the solution (eg. specifying exactly what new capacitors should be installed) so that TV service people everywhere are prepared to fix this.
Swapping the boards is easy enough that many customers would be satisfied with just a free part, but probably most customers would rather have someone install it for them. Given that the set is out of warranty, most customers would probably be OK with paying something out of pocket for this. Personally, I would have gladly paid $100 to have someone take care of this for me rather than spend many hours researching the problem, ordering parts, and doing the repair myself. But the alternative that was offered to me by Samsung authorized service was to pay $100 trip charge, $100 repair labor, and $150 for a new power supply board, for a total of $350. It just isn't acceptable that Samsung expects customers to pay that kind of money to correct this manufacturing defect.
Reply 5 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
http://s625.photobucket.com/albums/tt331/andrewsb62/samsung%20lcd%20bad%20capacitors/
Reply 6 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Thank you so much for your informative posts. My LNT5265F has been displaying the classic problems described by many owners: multiple power up cycles, pink dots down the screen once it does power up and over time just a black screen. Samsung denied any issues when I called for support and said they have no known problems that are wide spread based on what I described. A new PS board is $150 to $200 plus service costs. Yesterday, I took my TV apart and found that two of the three 1000uf 10V capacitors that you described had failed (buldged at the top). I went to RadioShack and purchased two 1000uf 35V capacitors (35V was the lowest voltage that they carried. They are slightly bigger than a 10V capacitor, but they fit on the board) After soldering in the new capacitors and putting the TV back together, everything is back to normal. The capacitors were $1.59 each. Thank you for sharing the detailed information in your posts and saving me hundreds of dollars.
Reply 7 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
My husband went to Radio Shack to by capacitors. He was surprised when the salesman asked him if we were repairing a LCD tv. The salesman said a man had been in that store the night before buying the same thing. Samsung needs to pay you!
Reply 8 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
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Reply 15 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
What is the board model #? I searched your TV model number and came up with a couple of possibilities like BN44-00192B and BN44-00208B, each for about $50 new.
https://www.encompassparts.com/webwiz/wwiz.asp?wwizmstr=WEB.SEARCH&mres=1&mrpn=SMGLN26A330J1DXZA
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Reply 19 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Reply 20 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
The first technician replaced the capacitor...we still had the same problem. The second technician replaced the whole board....still had the same problem...Now they tell us it is the main board. The one that draws all the power from the the power board. They said they can replace the power board, but if they do, the main board will blow it out again anyway. So, now we don't know what to do....
I hope that isn't your problem as well.
Reply 21 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Reply 22 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Did replacing the capacitors alone fix the problem without replacing the power supply board?
Thank you
Reply 23 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Reply 24 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Thank you for your insight. I had 2 blown caps and 3 more were bulging. I was able to find them at a local Radio Shack. Total cost of repair was under $15.00. Problem solved.
Reply 25 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
When the first repeat-failure happened, I inspected the power supply board, and could see no sign of problems with the capacitors that I had previously replaced. But I replaced them again anyway, and still the TV wouldn't start. So I ordered a brand new power supply board, and it worked first time. So I figured my repaired power supply board must have had some other hidden problem. I stuffed it in a closet.
A couple of months passed, and then the TV failed again, with exactly the same symptoms. So I ordered a new power supply board again, but this time, the new board didn't help. So I started to hunt around for another cause of the problem, and zeroed in on the inverter boards, of which there are four. Every time I turned on the TV, there was a buzzing sound for a few seconds, and by listening closely with the back off the TV I was able to determine that the buzz was coming from the lower right board, part INV52B24A (RL). Then I had a hunch -- we've probably all seen fluorescent lights have a tough time starting when they are cold. Well it seemed to me like the inverter was trying to start the fluorescent backlight and not quite getting it going. So following my crazy hunch I grabbed a hair dryer and started to heat up the entire area around the inverter boards, thinking that if I could get the fluorescent tubes warm, they might start up. Crazy? Well, it worked! After maybe two minutes of heating, the TV started up normally. The I powered down and left the TV off overnight. The next morning, it wouldn't start up again. So again, I grabbed the hair dryer and started heating, and again, it worked after a few minutes. Interestingly though, when the TV did start, there was still quite a bit of buzzing coming from the RL inverter board, but not any of the others. Then I got really close to the board and looked at all the transformers, and was amazed to see across one of the transformer casings, exactly where the buzz was coming from, what appeared to be a light scorch mark and a tiny crack. Could this be the problem? I decided to try to replace that board, and quickly found that this part doesn't appear to be sold by Samsung as a separate part, however I found a used board on "ShopJimmy" and decided to give it a shot. Board arrived a few days later, and upon installation, the TV immediately worked, with no hair dryer, and no buzz whatsoever. I turned it off for a couple of days to make sure it was completely cold, and it powered back up without problem. Then I decided to swap out the new power supply board with my original, repaired power supply board, and that worked too.
The TV has now worked fine for two weeks with the new inverter board. It's hard to know how the the power supply capacitor problem and the inverter problem are linked... maybe the original capacitor failure caused damage to the inverter transformer. Or maybe they are completely unrelated failures that coincidentally had the same symptoms. In any event, the TV works again, at least for now.
Reply 26 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
But before the capacitor repair, my set developed the problem with the dark picture at startup. And unfortunately, this problem still exists after the startup/capacitor problem was solved. I haven't tried the hair dryer test, and I haven't heard any noticeable buzzing. But, as described, the picture is dark for about 5 - 10 minutes after startup, then a subtle internal click and the normal brightness returns and the set is fine again.
You mentioned the inverters. Have you or has anyone else posted pictures or videos on the testing, repair or replacement of the inverter boards? After yesterday's success, I am willing to tackle that problem as well. Especially if I can get the kind of tech assistance that these forums provided on the capacitor issue.
Thanks very much for your posts, and I'm looking forward to more education.
Reply 27 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
Reply 28 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
I am not as proficient or willing to do the component level work but will have to have it repaired for the high on-site costs. I do agree that Samsung should stand behind this in some way for their faulty parts.
Reply 29 : Samsung LCD TV LN-T5265F Black Screen Diagnosis Help
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