Samsung LN-T4665fx/xaa version sq01 Power on Problem


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Samsung LN-T4665fx/xaa version sq01 Power on Problem

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readyakira
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Feb 9, 2009, 3:20 PM

Post #1 of 8 (23425 views)
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Samsung LN-T4665fx/xaa version sq01 Power on Problem	Can't Post

Got this TV very cheap and lately when you turn it on it takes a long time to start up. You can hear some relay's click, it will play the samsung chimes, and the red light in the lower right flashes but no picture. This continues for a few minutes then it usually powers up. once it does there is sometimes some Dots on the screen that look like they were torn from another spot on the screen and misplaced. At that point turning the TV of and on fixes that. But, this morning after 20minutes the TV had not powered up, and pressing the power button does not seem to stop it from attempting to turn on. So, I placed my ear close to the back of the TV about halfway across the top, and can hear a slight hissing sound when trying to turn on. Any Ideas? Should I even bother? It is/was an expensive TV in 2007, and has a beautiful pic when it is working so any help would be appreciated.

readyakira
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Mar 9, 2009, 4:15 PM

Post #2 of 8 (23375 views)
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Re: [readyakira] Samsung LN-T4665fx/xaa version sq01 Power on Problem [In reply to]	Can't Post

Since Nobody took the time to reply I wil give ya the info I found out. The power supply on these TV's are built with overrated and/or undertolerance parts. IE the 1000uf 10v caps that are on the power supply should have been a 25 or 35v cap instead. After replacing all the caps on the board with ones of the next voltage higher (same capacitance) the TV powers up great and has an awsome picture. The Main board chipset even seems to run a cooler temp! I assume this is due to the better quality caps being able to deliver a cleaner, more stable power to the rest of the Tele. Anyways what would have been a $389.00 power supply and god knows how much in labor cost less then $15 with shipping.

Happy Posting!

jrramirez1
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Mar 29, 2009, 1:07 AM

Post #3 of 8 (23322 views)
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Re: [readyakira] Samsung LN-T4665fx/xaa version sq01 Power on Problem [In reply to]	Can't Post

It seems I am having the exact same problem you are. I too have a Samsung 4665 that repeatedly powers itself up for a few minutes.
I was wondering how exactly did you fix your TV. I read that you replaced some capacitors, and I was wondering if you had any information so I could try to do the same. Like how many caps did you replace and what does it take to swap them out?
Thanks,
JR

rustym62
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Apr 5, 2009, 1:29 AM

Post #4 of 8 (23289 views)
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Re: [jrramirez1] Samsung LN-T4665fx/xaa version sq01 Power on Problem [In reply to]	Can't Post

I'm not sure that you have to replace all the caps,only if you can't tell which are bad. I've replaced a couple of these boards, (haven't done part change outs), but usually the caps that fail will look noticeably different from those around it. The top of the caps should be flat, if they look round on top they are swelling and are bad ones for sure. They will most likely be hot to the touch if set has been plugged in, be careful! Make sure you unplug AC before poking around in there! You would need to know how to solder and unsolder these components. Also these caps are electrolytic and can only be put in one way or they'll blow. They have a + and - lead you just make sure you put in the same way the originals are (usually the board next to the caps will be marked to tell you which way they go). Make sure the capacitance value is the same as the original. Caps also have a voltage value(known as working voltage) written on them too next to this capacitance value (you should go higher than the originals it sounds like in this case, never go lower!) If you aren't confident to try this, I'd buy the power supply (preferrably from Samsung just to make sure you get the right one) and install it myself. It's just a few screws and plugs holding it in. Hope this helps
Rusty

http://www.the-tv-dude.blogspot.com

(This post was edited by rustym62 on Apr 5, 2009, 1:33 AM)

NastyPope
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Dec 11, 2009, 6:54 PM

Post #5 of 8 (22006 views)
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Re: [readyakira] Samsung LN-T4665fx/xaa version sq01 Power on Problem [In reply to]	Can't Post

The last time I googled this problem, all I came away with was the knowledge that this problem plagued pretty much the entire Samsung LCD line for some unspecified period in 2007. Now, several months later, I'm glad I googled again, because after finding this thread, I opened up the TV, and, lo-and-behold, of 4 25V caps, 2 were shot, and of 3 10V caps, all 3 were toast. I ordered 3 16V caps to replace the 10s, and 4 35V caps to replace all 4 of the 25s (Why take the chance that the other 2 will go?) from MCM Electronics, for $21.50 after shipping charges.

The package arrived yesterday, and I replaced the caps this morning. The TV powered up in one shot, with a perfect picture (i.e. no random miscolored pixels).

Thank you, readyakira, for finding the exact source of the problem, so that the rest of us can do what Samsung seems unwilling to do: Fix our defective Samsung TVs at nothing more than a reasonable cost to us.

gqatbc
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Dec 1, 2011, 4:13 PM

Post #6 of 8 (15527 views)
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Re: [NastyPope] Samsung LN-T4665fx/xaa version sq01 Power on Problem [In reply to]	Can't Post

NastyPope, THANK YOU! Someone threw away this otherwise pristine television, presumably because they were told that a new power supply or main board would be necessary to repair the problem. I am a newbie to TV repair, but I do understand basic circuitry and can solder. CAn you tell me the part numbers of the 16V & 35V caps that you ordered from MCM? Thank you so much, this is an excellent television, and I am ecstatic to know that the repair may cost less than $30.

NastyPope
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Dec 1, 2011, 5:44 PM

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Re: [gqatbc] Samsung LN-T4665fx/xaa version sq01 Power on Problem [In reply to]	Can't Post

Unfortunately, I don't have a record of the order (It WAS two years ago, after all.), but if you open up the TV and take the cover off the power supply, simply look at the capacitors to find the capacitance (uF) you need, and then find those parts on the MCM Electronics website. You'll want to make sure to use the high-temperature (105 degree) variety, to ensure stability and longevity. EDIT: Remember to make sure to order the next-higher voltage rating than the caps the TV came equipped with.

I only have the most basic electrical and electronic experience, and had never de-soldered or soldered components on a PCB before (at least, not with the intention of it working afterwards), so if you're even remotely experienced in these areas, I'm sure you'll do just fine.

Oh, and for the record, two years after the repair, aside from some screen damage caused by 3 kids, the TV still works perfectly. :)

(This post was edited by NastyPope on Dec 1, 2011, 5:50 PM)

JohnRocks
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Dec 5, 2011, 8:01 AM

Post #8 of 8 (15449 views)
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Re: [readyakira] Samsung LN-T4665fx/xaa version sq01 Power on Problem [In reply to]	Can't Post

Place the new capacitors in place however you can get them to fit. Electrolytic capacitors (like the ones we're using) are polarized--that is, you have to make sure you put them in the right way. There should be a grey bar running down one side with a "-" in it .This is the negative leg of the cap. Be sure to put it in the same way the old one came out or you could damage the whole board.
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