TV Power Supply

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Old 08-18-12, 06:58 PM
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TV Power Supply

Is it possible for us to replace the power supply on the tv? It went out a few days ago and the tv is only 2 yrs old! Out of warranty of course. We don't have a repair man anywhere near us. 75 mi is the closest.
 
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Old 08-19-12, 05:54 AM
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You did not provide any information (brand, model number, what type of TV) about the TV so it's impossible to say. Is it a DC powered TV with an external power supply? If so then it should be a pretty simple task. Just find another power supply with the same output and connector/plug as the old one. If it's a normal household TV with a internal power supply then it's a much more involved process. Are you able to do repairs to circuit boards?
 
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Old 08-19-12, 07:06 AM
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TV Power Supply

Samsung Model LN52A750R1FXZA HD Flat screen wall mounted.

it's a normal household TV with internal power supply. I have limited board circuitry knowledge, do a lot of soldering. Have never taken the back off of a tv to look inside. I have seen some good you tube demo's on tv repair.
It just behooves me that a tv this new is already worthless.
 
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Old 08-19-12, 09:46 AM
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Did the tv go dead while watching it? Did it just stop coming on? Are the any lights on or flashing? Just need a little info about the problem to help point to the most likely problem.
 
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Old 08-19-12, 11:01 AM
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Yes, anything would be helpful. Was it doing anything odd before it died? Was it taking longer than usual to come on? Would you hear clicks as it tried a couple times before it finally came on? Was the picture blinking before it died? When you try to turn the tv on are there any lights on or blinking? Are they blinking in a pattern?
 
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Old 08-19-12, 11:42 AM
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TV Power Supply

The tv would not come on when I powered it up. If I held down the power button it came on 2 separate times then after that it would not come on at all. It was trying, but all it does is click as if I turned it on and make the little tone over and over. It will do that as long as there is power to it. The red light that shows power to the unit stays on until I unplug it from the wall. The picture never ever flickered. I called Costco Concierge and they said it is the power supply and that it is out of warranty.

Samsung tech support agreed that it is the power supply and won't do anything other than provide me with a repairman's phone number for my out of pocket expense. I sat on hold for 1 hr and 30 min with Samsung support. This will be my last Samsung product.

We thought we could look at the capacitors inside the power supply box to see if that's the problem. It's really infuriating to have an expensive 2 1/2 yr old tv be worthless.
I'm tempted to return it to Costco.
 
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Old 08-19-12, 12:58 PM
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Well, it sounds like you've nailed it down pretty well to the power supply and like you surmised it's possibly a bad capacitor or two. It sounds like you have two choices. Take it to someone or try to fix it yourself. If you decide to take it to someone I'd do it without even opening the case.

If you decide to try and fix it yourself I'd clear off a place where you can leave the TV for a while in case you have to wait for parts. Lay it face down on a couple towels and remove the screws from the back and remove the back. Look for the power supply board (no, I don't know an easy way to describe what it should look like) it probably will have several can style capacitors. Luckily, larger capacitors are still through hole so they are replaceable by a good DIY'er without too many specialized tools.

First I'd get a good light and look closely at the capacitors. They should have straight sides and a flat top. If the sides or top are bulged it's probably bad. If none appear bad I'd probably replace them all since they are so inexpensive. If you have a digital multimeter you could test them but I don't think it's worth buying a meter since it will cost many times more than new caps.

Before removing anything from the board take some good photos just in case you need to reference what goes where. I have a number of pinball machines of various ages so I often get electronic parts from my pinball supply companies (online). You can also order them from places like DigiKey, Mouser or Jameco. I tend to avoid the Shack as much as possible especially for capacitors where freshness sorta matters.

You mentioned that you've done a lot of soldering so I assume you have an iron, hopefully with a small tip, flux and solder. Do you have something for desoldering? I like the spring loaded suction type and they are pretty inexpensive.

The only other tip I'd offer is once you have the back off I would not wear shoes. Go barefoot or at least don't shuffle your feet to avoid generating a static charge and ground yourself by touching the screw in the center of an electrical outlet. If the TV's been unplugged for a while the caps should self discharge and if you've grounded yourself it's ok to touch the electronics. A static shock should not hurt the big caps you'll be working on but it's more for just in case you touch some of the other, more sensitive components. Generally the tinier the part is or the leads going to it, it is more sensitive.
 
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Old 08-20-12, 05:03 AM
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The power supply part # BN44-00201A looks to be the right replacement. It's only about $70 .
 
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Old 08-20-12, 05:49 AM
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I'll take capacitors for 100 alex...

This sounds a lot like my ~3yrs old LG. Was two caps that have been discontinued because they failed regularly.

I'll further Pilot Dane's post with some tips to make life easier when working on these (or any electronic unit).
You'll need a good desk lamp or flashlight, digital camera (optional), small zip lock bags and a marker.
Grab a couple zip lock type baggies and the marker. Use a different bag for each screw type/area and clearly mark on the bag what it is. Take photos of everything you remove before removing it so you know what goes where later on.

Once you have the back off (be careful, they tend to be flimsy plastic), snap a picture of each area or circuit board. This can be useful as sometimes a picture is easier to spot stuff then the actual device (don't know why, but it is).

Your power supply will more then likely be where the power plugs in. Odds of it being the issue is not 100%. You have power after all (lights and what not).

Using your desk lamp or flashlight, look over each board for capcitors that look like they are mounted at a slant, or have a bulged top. A bad cap may not leak, but can swell on the top or bottom.

Once you know what cap(s) are bad, and have replacements in hand, take note of which lead goes where (generally marked on the cap with a plus sign and negative sign).
Use a solder sucker when removing the caps. This will make installing the new ones so much easier and save potentially damaging the circuit board (the traces are not really robust).


The photos below are from my LG Plasma TV that acted very similar to yours. This will give you an idea what you are looking for. Be very, very patient searching.

This is the overall shot. The power comes in the middle bottom of the tv. The affected caps are on the top middle board. They where located in the bottom right hand side of that board.
Name:  French River-20120601-00614sm.jpg
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This is what my bad caps looked like. The black color on the top is not a 100% indicator of them being bad. The bulge on the top, and lean of the other (blow the plug out the bottom) was how I spotted them.
Name:  French River-20120522-00576sm.jpg
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The cost of my repair was ~$4.56CND (shipping and extra set of caps included).
 
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Old 08-20-12, 01:23 PM
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The cost of my repair was ~$4.56CND

Is that in American dollars? Canadian? $4.56 CND?
 
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Old 08-20-12, 01:28 PM
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The power supply part # BN44-00201A looks to be the right replacement

How can u tell that is the right part? Is that the whole power supply box?
 
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Old 08-20-12, 02:20 PM
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Is that in American dollars? Canadian? $4.56 CND?
That is Canadian Dollar (which is about the same as US dollar).
Was 4 capacitors (two spares) and shipping off ebay.
 
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Old 08-20-12, 07:51 PM
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That's the whole board. No soldering to do. Just replace the whole thing. When I put in your model # , two part#'s came up for your set for the power supply. Just google the model # plus "parts" and then find the power module. You could take the back off and look for a pic of the power supply to make certain it matches.
 
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Old 08-20-12, 08:58 PM
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Talk about a shocker, the president? of the company called this eve and offered to have a tv repair person come out and fix it for free! A one time deal he said. I said send him on out!
But if there's anything else wrong with the tv I will be responsible for it. I wrote to the ceo and told them how I felt about the way they built and sold these tv's. I guess that's why I got the call. I told him word of mouth will be my mode of complaint. FB, Google+, Twitter, etc. So we'll see.
I was looking forward to delving into the back of the tv.
 
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