Repair Samsung LCD TV -Relay Clicks, Shuts Off, Won't Come On

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Introduction: Repair Samsung LCD TV -Relay Clicks, Shuts Off, Won't Come On

DISCLAIMER - If you attempt to repair your own set, expect to void any warranty that might still exist.  If you do additional damage, it's your own responsibility.  Further, you are working with an appliance that is powered from you house mains.  There is risk of shock with the potential of death or serious harm.  Know what you are doing, and how to work safely with an electrical appliance.


Recently my 3+ year old 40" Samsung LCD TV started taking a long time to start up, with several cycles of relays clicking.  In searching the net I found that others were having similar problems.  Apparently, Samsung's power supply on several LCD models was somewhat under-designed, with four capacitors that slowly fail over time and which leads to the symptoms in the title.
There are several options for repair: 1) Take the set to a qualified repair shop (est $300 - $500). 2) Buy a new, replacement, power supply ($100 - $175). 3) Replace the offending capacitors ($4.00 - $15.00)

I chose option 3, spending $15.00 for a Samsung repair kit (contains 4-1000 uF, 25V, 105 degree C capacitors and "instructions").  If you want to keep the costs to a minimum, you can order an appropriate set of capacitors from Digi-Key or Mouser for about $0.65 each + s/h.

Tools you need:
Phillips screw driver able to reach recessed screws (about 1" deep)
Soldering Iron for general purpose electronic components.

Note: According to the Samsung repair kit instructions, this repair works with the following models:
LNT4042H
LNT4042HTX/XAA
LNT4053HTX/XAA
LNT4053HX/XAA
LNT4053HX/XAC
LNT405HAX/XAA
LNT4061F
LNT4061FX
LNT4061FX/XAA
LNT4061FX/XAC
LNT4061FX/XAP
LNT4065XF/XAA
LNT4066F
LNT4066FX/XAA

Step 1: Remove the Back of the Set

Place monitor face down on a cushioned table. Remove screws from cover and remove screws from the stand. (If stand is attached)

I have an optional wall mount setup, requiring removal of the wall mount hardware from the rear cover - a total of 4 screws.

Step 2: Disconnect and Remove the Power Supply


There are seven screws securing the power supply, as well as the various cable connecting to other components.  Remove the cables, remove the screws, and then lift out the power supply.
IMPORTANT NOTE - While capacitors are not particularly sensitive to Electrostatic Discharge (ESD), most of the components on the power supply and other boards ARE!  Take appropriate measure to avoid static discharge (grounding straps, etc.), or risk totally frying your set's electronics.  Should this occur, you're no longer facing an inexpensive repair.

Step 3: Identify, De-Solder, and Remove the Failing Capacitors

There are four electrolytic capacitors to be removed: CM812, CM811, CM817, CS806.  These are clearly noted on both the front and rear surfaces of the power supply's circuit board.  (If you need a tutorial on how to de-solder "thru-hole" components, there are both text and video available on the net.)

You will likely see that the four capacitors of interest display bulging caps, and may even be leaking material.  On my set, only one showed any leakage, but all four were bulging.  The circuit they were used in is marked at 5.4V.  Based on my readings in electronics, capacitors should, in general, be rated for a voltage that is at least double the planned circuit.  Given that the original capacitors are rated at 10V, it would seem to indicate that fudging a bit here can lead to premature failure. 

Step 4: Solder-in the Replacement Capacitors

The capacitors are polarized.  This means you MUST pay attention to the positive and negative leads on the capacitors.  The polarity is clearly identified on both the capacitors, there is a stripe down the side of a polarized capacitor with the minus sign, and the circuit board (both front and back indicate the polarity).  Failure to match polarity is BAD.  At the best, the capacitors will fail, in the worst case, they explode, and I assume, don't do anything good to the circuit board either.

Step 5: Replace the Repaired Power Supply and Attach the Rear Cover

Replace your newly repaired power supply, connect the internal cables to the other components.  Re-attach the rear cover, stand (if used), or wall mount brackets. Attach the external cables (Video, Antenna, etc.).  And, finally, plug in the power cord.  If all has gone well, press the power button and you'll see your set power up as it did when it was new.

NOTE:  The photo of my working TV is NOT representative of the image!  The horizontal striations are an artifact.

Step 6: Other Resources

You may find the following useful:

Samsung LCD Power Supply Repair Kit - BN44-00167A
Samsung Replacement Power Supply - BN44-00167F
Digi-Key - www.digikey.com

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Hi, I was just given one of these, 40',. Same issue lol. Has a really nice picture when it's on. So I really want to fix it. Been doing a lot of research about the problem and have looked through lots of articles and videos but I like this post. Thanks for the posting it. I know its old but good info is good info! I wanted to ask if you or anyone else who may see this, know of a good place to order the caps? Also I noticed theres 2 fuses, I was thinking about going ahead and replacing those too while I'm in there, couldn't hurt, rt? OK, THANKS! again and please let me know if you know of any place.

Hi Clyde,

For online purchases I use Digi-Key (www.digikey.com) and mouser (www.mouser.com). You will want to measure the diameter of the existing capacitors and check the lead spacing so you can order caps that will physically fit. Their voltage rating should probably be greater than the original 10V that were installed.

Bob

I was just thinking they might be tied together is because they do it intermittently and how the power is cycling on n off. I know they are different and not the same circuits but wondered if the fast powering on n off could maybe cause it. As you can tell I'm no electronics expert lol. I was researching how to "fix" stuck pixels and some things I read made me think it might. Guess I'll take that on once I take care of the caps. Thanks for all the help!

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Thanks! I was able to find them @ parts express. Also there were comments from people who used them for exactly the same thing. I did have another question; while dealing with this issue did you or anyone else notice any stuck pixels, sometimes when when the TV finally turned on? Sometimes when mine comes on I will have that but if I turn on and off a few times they will go away. I have a feeling it's connected somehow. And one more thing, I noticed 2 fuses so I was thinking about changing those to while I was in there. Any thoughts? Thanks again!

The stuck pixels are unlikely to be associated with the capacitors - they are part of the power supply. The stuck pixels are likely to be somewhere in the video processor/display. Sounds more like a logic problem since they aren't always on. FWIW, I don't have any stuck pixels.

My thought on the fuses: Should be fine... If they'd failed, you'd have nothing showing, but if they're cheap... Your call. :)

So I have a Samsung UN55B7100WF and I got the problem where the TV would click but wouldn't power on. After reading a lot of forms & watching YouTube videos I though it could be a capacitor, because that seemed to be the most common problem. I took off the back and looked and the power board and all the capacitors looks fine. None were swollen nor had the top of the caps looking like they burst. Never the less I figured it could still be the board because some people say it could be hard to tell. I purchased a new board from PartStore.Com and it arrived today. About 20 minutes ago I took out the old board and installed the new board and hooked all the connections back up. When I tried to power it up the same thing happened. Click...click...click... never powering fulling up. No led showed or anything. So... The power board was a waste. It was about $173 after tax and shipping, and hopefully I get the majority of my money back. I did read it could be the TV board, but that is around $325 and if I am going to spend $600 in total I might as well just get a new TV. So all in all I didn't have any luck when replacing the power board. I'm still interested in what anyone thinks the problem could be if a new power board was put in and the clicking without it fully powering up could be attributed to.

I also replace the power supply but nothing. It still didn't come on. Someone told me to replace the main board and it should work.

Did you find out what the problem was? I'm having the same issue.

GulfcoastCG,

I wish I could help. As I'm not an electronics engineer, your problems far exceed what little I do know. I understand your frustration, and like you, I would be looking to limit the cost.

Bob

The set I have, LN-T4671F, was actually covered under a free replacement from Samsung. They were able to schedule a person to come out to my home and replace the whole power supply on my set the day after I called for support. It was only about a half hour to do the repair and I didn't pay anything. Comparing the two supplies, they actually had different value capacitors. I don't remember the values now, but the blown ones had lower values. I would recommend calling Samsung to make sure you're not covered before attempting this repair yourself. If you have to do this yourself however, thanks for this ible!