Friday, August 12, 2011

Repairing a Samsung LCD TV With Clicking Relays (LNT4661F)

This is a write-up on how to repair a Samsung TV that experiences problems powering up.  The most common symptoms of this failure include the sound of clicking relays when the TV is powered up, and the red LED indicator on the front of the TV may flash on and off.


Typically after the relays click a few times, the TV will eventually come on.  However in time the relays will need to click on and off more and more times before the TV will come on... and eventually the TV will likely just cycle the relays over and over and it will never come on.


If you just want the instructions on how to do this repair, skip to step 1 below.  If you want my personal saga explaining why I decided to perform this repair myself... read on.


In my case, I have experienced this failure on two separate occasions.  I originally bought this TV back in 2008, and sometime within the first year I began to hear the dreaded clicking relays suggesting there was a problem.  About a week after this started I was watching TV one evening and all of the sudden it sounded like a firecracker went off inside of the TV.  From experience I knew this meant a capacitor most likely blew up... however since the TV was still under warranty I wasn't about to crack it open to investigate.


I placed a call to Samsung and started the saga of getting the TV repaired.  Long story short the process involved at least half a dozen calls, several weeks of waiting for parts and a technician, and having to take a day off of work to be around when the service tech actually showed up.  Did I mention that the TV failed about a week before the Superbowl and there was no way to get it fixed before the game?  Yea... perfect timing.


Eventually the technician showed up and as soon as he opened the back of the TV and removed the shield from the circuit board it was very obvious which capacitors had blown.  The technician removed and replaced the power supply board with an updated version, and then closed the TV up at which time we tested it and verified it was working as good as new.


That was early 2009... and up until a few weeks ago the TV worked fine.  However around two weeks ago I noticed when the TV was powered up the red LED on the front seemed to blink several times before it would power up.  Then a few days after that, the dreaded clicking relays started.  As the days progressed it took longer and longer for the TV to power up and it became obvious it was only days away from another total failure.


I did a bit of research and discovered I wasn't alone.  In fact many users of this particular model of television (the Samsung LNT4661F 46 inch LCD HDTV) had experienced the same symptoms, and it all boiled down to bad capacitors.  It seemed there were a few ways to fix it... the easiest of which is to simply replace the power supply board.  However with a little bit of electronics knowledge and some replacement capacitors... it is much less expensive to simply replace the bad capacitors rather than bearing the expense of the entire circuit board.


Therefore in order to verify the issue I removed the back of the TV along with the metal shielding that covers the power supply board and with a little inspection it was very obvious which capacitors were failing.  As you can see from the image below, two of the capacitors show signs of failure and are bulging.  One of them was even showing a crack on the top which means it was probably days before a total failure.




Reading the specs from the side of the capacitors showed that they were 10V caps rated at 2200uF and had a max operating temperature specification of 105°C.  In my case it was only these two capacitors that were failing, however others have reported that the 1000uF capacitors directly beside the 2200uF caps had also failed.


In any case, now that I knew what the source of the issue was, I decided it was time to order some replacements.  However based upon markings on the board as well as information I had found online, it seems 10V capacitors are simply too small which is what contributed to the premature failure.  It appears this particular circuit was designed for 12V capacitors yet Samsung decided to use 10V caps instead.  It stands to reason why they wouldn't last.  Therefore, in order to prevent this from happening again I opted to replace the caps with 16V capacitors, but others have used 24V or even 50V replacements... it is just a matter of what is available.  A higher voltage capacitor doesn't mean it will run at a higher voltage... merely that it is capable of handling that voltage.  In this case, having a little extra buffer was a good thing as the caps would be running at a voltage well under spec.


It just so happens a friend of mine was in the process ordering some parts for himself, so he just added a few of the capacitors to his order and they were on the way.  In the meantime, it was time to get started removing the old capacitors and prepping the board for the replacements.


Step 1: Remove the power supply board.  Ok so technically step 1 would be remove the back of the TV and then remove the shield covering the board itself... but if you can't figure that part out on your own you probably shouldn't even attempt to replace the capacitors yourself.  


To remove the board, you will want to disconnect all of the various connectors that run into the board and then remove the six screws that hold the board down to the mounting plate / chassis.  It isn't a bad idea to take a photo to ensure you get all of the connectors in the right places upon re-installation (or just use my photo as a guide).  The capacitors being replaced are shown at the upper right hand corner of this board.






Step 2:  Desolder the old capacitors.  In my case, this involved CM852 and CM853.  You can see from the image below what the top of the board looks like after the capacitors have been removed.  I won't go into great detail here about how to actually desolder these since it is assumed if you are attempting this you have some basic knowledge on how to use a soldering iron, but it is helpful to have some desoldering braid and/or a solder sucker (desoldering pump) to remove the old solder as you heat up the leads.  






And this is what the bottom of the board looks like after the capacitors have been removed.  Note that there are polarity markings on both sides of the board.  Try not to apply too much heat to the board as you don't want to inadvertently harm the solder traces on the board.






Step 3:  Paying attention to the polarity of the capacitors (the shaded area of the board corresponds to the negative lead of the capacitor), insert the leads of the replacement capacitors through the holes in the circuit board and bend them outward to hold the capacitors tight against the board.  Apply heat to each lead and solder them in place.






Step 4:  Using a side cutters, trim the leads of the capacitors.  Some may prefer to cut the leads prior to soldering, but I prefer to do so after they are soldered in place just in case I need to make any adjustments.  After trimming, verify the solder joints are intact and are solid.  The image below shows the end result from the bottom of the board.






And this is what the new capacitors look like from the top of the board.  The new caps were slightly larger than the originals, but they fit just fine.






Here is another side angle showing the new capacitors in place.  Several of the other original caps (the lighter blue caps in the image) may also need to be replaced if they show signs of failure, but in my case they all appear ok.




Step 5:  Reinstall the power supply board back into the TV chassis.  Tighten all six mounting screws, and ensure all of the various connectors are reconnected properly.  Once everything looks ok, reinstall the metal shield that covers the power supply board as shown in the image below.

If there is any doubt about the location of the various connectors... simply refer to the image in step 1 above.  However aside from forgetting to actually install one, it is nearly impossible to do  this step incorrectly since aside from the two in the lower left corner, all of the connectors are unique.





Step 6:  Reattach the back of the TV, install the stand and/or wall mount cover plate... connect the TV to a video source, plug it in, power it up and enjoy!


Step-Brothers Anyone?


The replacement capacitors cost under a buck each plus a few bucks for shipping, so the end result was a repair for around $5.  I had the soldering iron, soldering braid, and solder on hand already so there was no additional cost there.  Total time from start to finish (not counting the time I was awaiting parts delivery) was approximately 20 minutes.


Considering the cost for a technician to come out and replace the board could easily top $300... I think this repair is more than worth it.  With a little luck the third time will be a charm so hopefully I won't need to do this again!


If you found this post helpful, or if you have any questions about the process, please leave a comment and let me know.

52 comments:

  1. I would like to thank you for this information. I had the same problem and I followed your post and had it fixed in no time. I work in an elelctronics factory and was able to get my components for free. I went with a 16v as that was the first one I found. You saved me a bundle of money and I was able to fix my tv for free. Anyone who reads this post should be able to do the same. It was very well written and the pics were excellent. I saw the damage as soon as I opened it. My model was the LN-74665F with the same problem. So thank you again for saving me money. I will sign anonymous so I don't get fired from my job for taking the parts!!!

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  2. Having the Same problem with my Samsung, model LN-T4661F. Could you forward to me the Specific Numbers needing for ordering the replacment capacitors? All the Soldering Equipment i have here at home. Thanks in advance

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  3. CM852 and CM853 Capaitor replacements should be 2200 Microfarads 25 Volts for the LN-T4661F Samsung.

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  4. I ordered mine from digi-key. Part number for the 2200uf, 16V pieces that I needed was 565-1937-ND.

    http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&KeyWords=565-1937-ND&x=0&y=0

    Of course a higher voltage cap will work so the 25V option is fine too.

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  5. Same model TV, bought mine in 2007. My board's a bit different - no 2200 microfarad caps, all mine near the heat sink are 1000 mf. I have four in a straight line next to the heat sink. The two on either end are 25v and look perfect. The two in the middle are clearly bulging - and are 10v. So what's interesting is that Samsung managed to screw this up in different board configurations for the same model TV! New caps ordered, can't wait.

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  6. You are the man Craig! I ordered the 1000uF and 2200uF (both in 16V and 105C) from ebay, total including shipping under $4 shipped to my mother home.
    I followed your perfect instructions and my mother's Samsung TV has a slightly different power board. Once I opened it, I immediately saw the issue just like your pictures - 2 of the 2200uf were cracked on top with a black cross sign (CM812 and CM813). I noticed there is another 2200uf 10V on the board (CS804) and it seems OK. I decided while I am there, I will replace it with the 2200uf 16V.
    After about 2 hours in unscrewing 20+ screws, removed the power board, replaced 3 2200uF cap (CM812, CM813, CS804), put it back all together -- WOW! TV is on and working great. We have been watching it for the last 2 hours without any issue.
    Thanks again Craig! Wish I can put up my pictures for others to look at as reference material.

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  7. It seems there are a few different variations of the power board - Samsung revised the board later but didn't seem to solve all of the problems.

    Glad to see you were able to fix your TV for $4... that is awesome. Amazing to think a TV repair shop would charge $300 for a repair and all they do is swap the power board.

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  8. Thanks for this information. I was able to fix my TV using this, and it works great now. The power board on my LNT-4661F was a little different from the one posted. Nonetheless spotting the faulty capacitors was simple enough (there were 3 of them, 2 were already leaking a little, and the 3rd one was growing slowly). I replaced them with 1000uf 16V 105C ones and its working great so far.

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  9. Is it at all dangerous to work with capacitors that have contained a charge? I took a course in circuits and I recall my professor deterring us from messing with capacitors because they can store a tremendous charge, but I might be mistaken.

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    1. In theory yes, but capacitors of this size don't hold enough of a charge to be of any concern. I suspect what your professor was referring to are high voltage capacitors such as those found in tube televisions or other high voltage electronics.

      In this case, there aren't any issues working with these small capacitors and you don't even need to worry about discharging them as they pretty much discharge themselves within a minute of power being removed. Thus, but the time you get the case of the television open, there will be no voltage concerns with the caps.

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  10. Thank you VERY much I had the same problem, and it started taking 15 minutes to startup yesterday. I took i tapart today and it was the same 2 capacitors blown. i went to the local electronics supply store and replaced the capacitors. Everything's back to normal!

    Thank you!!!

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    Replies
    1. Glad it worked for you - that's awesome!

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  11. Followed these instructions and fixed my TV. Can't believe it. Thanks very very much.

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    Replies
    1. Another success story - glad to hear it!

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  12. hey craig,
    thank you for investing you'r time writing this tutorial.
    i have the same problem with my samsung(cant rem the model)but the board is slightly different.
    it is a 40' samsung lcd.
    i have the relay clicking problem and i opened the tv(before reading you'r tutorial).
    i noticed 3 1000uf 10v blown caps,went to electronics store and replaced them with the exact capacitors specs(10v 1000uf)
    for my big surprise-it didnt solved the problem so i looked online and realized it is a very common problem with samsung lcd's.
    i have a minor knowledge with electronics and i was wondering after reading you'r guide->do you think replacing the NEW capacitors i installed with ones with higher voltage(16 or 25 as mentioned)can make a difference? and if so do i still be needing the same capacity(1000uf) or i can just use higher capacity?
    thank's ahead for you'r answer,rami.

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    1. One of the issues with the Samsung power supplies is the caps are underrated in terms of voltage. You wouldn't want to go with a different microfarad (uF) rating, but using a higher voltage capacitor is recommended in this application.

      I believe in your case what you might find this there are a couple more capacitors that could be failing elsewhere on the same or another power supply board. I would check the board for any other bulging capacitors and see if maybe that is the source of your issue. Then if that doesn't seem to help you might want to consider upgrading a few of the capacitors you already replaced with a higher voltage.

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  13. I did this on a samsung lcd 40" model .LE40A557P2CXXE for 10 minutes ago here from sweden. So exited that it worked. thank you for your blogspot!

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    Replies
    1. That is awesome news - who would have thought this would be a worldwide issue?

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  14. This might not be the ideal place to request this, but I’m trying to find a reliable shop to repair our television online and and have no method to find out who is the very best. I uncovered this website which is I find reliable and wanted to see if any person has any reviews on them. Richmond TV Repairs. http://richmondtvrepairs.com
    Please help me with this as my wife and I have been struggling to find a good/reliable shop to repair our television.

    ReplyDelete
    Replies
    1. Might want to brush up on your marketing skills there Carey. Generally speaking, when you spam a comment pretending to ask about a random business, it isn't a good idea to link to your Google Plus profile which clearly shows you are employed by them.

      Also a quick Google search shows that you have cut and pasted this same exact comment on dozens upon dozens of forums, blogs, and websites as you pretend to be a customer.

      Personally I find spam incredibly tasteless. It is one thing to offer your services in a clear and honest manner, but when you pretend to be someone in need just to post the name of your little repair shop it is sad and pathetic. I for one would never recommend your services, and if someone does need the services of a repair shop I hope they do business elsewhere.

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  15. Thanks you ! Same bad capacitor! I'm really happy. Never (de) soldering before that. TV work as new and I realize than the clicking was already when tv were new!

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  16. Hi,

    I had the same problem and figured out visually the bad capacitors and replaced, unfortunately that didn't solve the problem, the relay keeps clicking on and off and the TV never starts

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  17. Did you check for other bulging capacitors? Maybe on other adjacent boards? Did you install one of the caps backwards meaning negative-cap-wire-soldered-to-positive-on-the-board, and positive-cap-wire-soldered-to-negative-on-the-board? Verify the grey shaded area on bottom of board is where the negative wire of the cap is soldered. Are all of your solder points firmly solidified to the cap wires?

    I would do these things:
    1 check for any bulging caps that might have been missed.
    2 If none found then desolder/remove, then re-attach/resolder the replacement caps since you likely have a bad connection (solder not touching cap wire), or backwards installed cap.
    3 If all those things don't work, buy a replacement board instead. More expensive but should work if the flashing red light and long startup time were indeed your problem. Of course you might have the same problem down the road since Samsung uses under-rated caps on these boards. Maybe take the replacement board and new caps to a friend /relative who can solder? You buy the beer and pizza and do it while watching the game at their house since your TV is broke anyways.

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    Replies
    1. You're right on all counts - those are things to consider and look for.

      If all else fails a new power board will probably solve the issue. They will cost anywhere from $100 to $200 depending upon the model and source of the board, but if it fixes the television it is probably worth it.

      However, 99 times out of 100 this issue will boil down to bad capacitors somewhere... so it is just a matter of finding any which have failed or appear to be on the way to failing (bulging and/or leaking capacitors).

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  18. hi, thanks for the blog, i have been reading up on this for the last few weeks since my tv wouldn't turn on. I have replaced al the capacitors with those of the same ratings even ones which weren't visibly 'bulging'. put everything back together and it still doesnt work, the relay is still making that clicking noise.
    Thanks,
    Maaz

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    Replies
    1. Well as with all electronics there is never one single solution. It is possible you have a failure in another component in your power supply circuit which is limiting the amount of voltage being provided to the other components. I obviously can't diagnose your issue based upon a few sentences, but you may need to consider replacing the actual power supply board. They had typically be found online at places like eBay.

      Or, if you don't want to gamble you can always take it to a certified Samsung repair facility and let them diagnose the issue for you. At least that way you won't just be replacing parts in the hopes it will solve the issue.

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  19. Thank you so much for writing this. I wish I would've found it sooner but oh well, we got a new TV (and we were due anyway). Now I know how to fix another electronic issue and I have another nice big TV for wherever I want to put it! And it cost us under $10 You have a fantastic blog and I am so glad I found it.

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  20. Thanks for the info. I did the same type of repair on a Samsung 22 inch monitor. The TV now tries to start 3 times and finally makes it. Sometimes with numerous red dots. I assumed it was the same sort of capacitor issue and now I am pretty sure. never ever 100% sure of anything.

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  21. Just woundering if I can us larger uf like 3300 so a 16v 3300 uf I have a couple in some old electronics I can reuse .
    Thank you for reply ahead of time.

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    1. The short answer - it depends. Typically speaking you can increase the rating of a capacitor if the capacitor is used for filtering. I have seen people increase their capacitors up to 100% above the original with no issues. In your case you are talking about a 50% increase so in theory this should give you no problems.

      That being said, I do not have detailed schematics of this circuit so I can't be 100% certain of how it might react with a larger capacitor. I suspect it would work just fine, but since I don't know everything about the board or the circuit I really can't guarantee anything. For the cost of the same size capacitor being a few dollars - is this an area you really want to play with? It is your call of course - I'm sure you would be fine either way, but if it is my television I'd opt to buy the same size caps with a slightly higher voltage than the original (16V seems perfect IMO). It might take a few more days to order them and it will cost a few bucks but why take the risk?

      Also, you mentioned the caps you were talking about were from "old electronics". I'd be hesitant to pull and reuse a capacitor from an old piece of equipment anyway - for the cost of new it just isn't worth it. Sort of like buying used tires for a new car - the logic just doesn't compute for me.

      Best of luck with your repair.

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    2. you may replace 1000uF with 1200 but not any higher for many reasons, but in no way you try to use lower than 1000uF or else it will blow on your face, or even worse burn your house. As for the voltage, you can use 16V, 25V, or even 35V to replace the 10V caps. With this being said, the clicking problem can be caused by a multitude of failing components,like a power regulator regulator (transistor), a diode, or, in some cases, abad cap or transformer on the inverter board. One need to know how to use a DVM and he can check these one by one (they're few), as well as make some readings of the output voltages on the three boards. Beneficial reminder ...ELECTRICITY KILLS.
      TV repair engineer for more than 35 years.

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  22. Samsung USA and Canada will fix your tv for free IF it is definitely the capacitors. Just call their toll free, tell the model number and serial number. They have a list and will tell you if you quality. There was some class action lawsuit in the USA about this issue, which lead to Samsung deciding to fix the tv's on the list for free. If it turns out to be something else (not likely) than you pay $100. Only problem is the repair company puts in the same cheap capacitors so you will have the problem in a few years again, but by then you can fix it yourself.

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    1. The only problem with this that in my case they had already repaired the television once therefore I doubt they would have been willing to do so again.

      Also, in my case it was a nightmare to find a repair tech who would actually come to my home. There are several repair shops in town that I would have thought could fix my television, but according to Samsung the only authorized tech was 60 miles away. Needless to say the repair was slow and had they required me to take my television in to a repair shop it would have been a rather large hassle.

      Plus, as you say, if they put in the same cheap capacitors I would just end up right back where I started in a year or two. Instead I replaced them myself and here we are over two years later and the set is still working perfectly. This is still my primarily television and get used quite a bit - so I clearly am happy with the results.

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  23. Thanks for this article - it worked perfectly for me.

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  24. Excellent article, cleared some things up for me!

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  25. Replies
    1. I've had two Samsung TVs die due to this issue (which I bought at the same time). The first, a 52", died within about a week, and the PCB got replaced by a repair man. After that no problems (now about 5 years old). The second, a 40" had been limping along for years now with the clicking relays behavior, but this weekend it finally gave out. I was a little intimidated by the rework even though I've done harder stuff for my job. It turned out to be super easy, and now my 40" is back in action and actually working better than before I fixed it (turns on first time, no problem). Thanks so much for taking the time to document this!

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    2. Thank you very much,My 46 inch TV is working perfectly now.replaced 3 caps and that did the trick!

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  26. Great article. Fixed mine in about an hour, as I took pictures, and did some extra exploring.
    Fantastuc

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  27. Nicely detailed instructions. Thanks for keeping it simple.

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  28. Thanks for this, confirmed my suspicion about a TV I bought. My model is LN46A530 and has the exact same markings on the board for the capacitors that failed.

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  29. Thank you for this guide. Between this and the comments, I was able to identify and repair the tv. :)

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  30. I am going to try this...I hope it works.

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  31. Is the metal shielding necessary??

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    1. I can't really say if it is necessary. I suspect part of it is to meet emissions requirements (measuring RF leakage etc.), but it may also prevent some components interfering with image quality. I noticed the shielding is all grounded so I'm guessing it serves a purpose.

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  32. Shorting the two post together after power is removed will discharge a cap safely

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  33. I have a Samsung lnt4665fx/xaa I have found the CM852 and CM853 capacitors to be bad both are 2200uF , 10V. I have seen that some people are recommending using 1000uf 35v capacitors. Can this be done or what would you recommend?

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    1. Generally you are ok with using a cap that is rated for a higher voltage, but you should stick with the same microfarad rating (so if you need a 2200uf rated cap, replace it with the same uf rating). There may be cases where this isn't necessary, but without knowing a lot about the specific function and the circuit, I wouldn't risk it.

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  34. This comment has been removed by a blog administrator.

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  35. Opened up my LN46A550P3F and didn't find any bulging capacitors but replaced them anyhow. Same issue. Popped in a new power board. Same thing. Any thoughts on next step? Thanks in advance!

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    1. In some cases when the power board fries it can take one of the sustain boards with it as well (X or Y). So that would be the next option, but honestly I'd strongly weigh whether it is worth repairing it at this point. With the age of these TVs and the fact they lack the features of newer sets (4k, HDR, Dolby Atmos, Smart features etc.) in many cases it just isn't worth spending the money to fix them knowing something else could go wrong at any moment.

      With my set, eventually the connections to the actual LCD panel started to fail and I was getting some random lines on the screen. I opted to give up at that point and just sent it to the recycle bin instead. I was able to replace it with a 4k Smart TV (LG) for around $400 so it was well worth the upgrade.

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