Samsung LN-S4041D Repaired - Finally

[rxchng]

Like some of you, I replaced some bad caps but the black screen problem was still there. Then, I kept reading everything I could find on the internet and finally I found the culprit!

It has to do with "cold solder joint". Apparently it's common to several Samsung models. If replacing caps didn't solve your problem, this may help.

Thanks to Madhu from TECHREPORT forum (http://techreport.com/forums/viewtop...=a&start=390):

"After some testing I noticed that under the black housing on the left corner module there was some kind of buzzing noise like there was a short in the circuit. After inspecting underneath the power supply unit, I noticed that one of the soldering joints for the black unit above was cracked. So like everyone else I head to Rat Shack and picked up a 15/30 watt soldering iron and some rosin core solder. It was my first time trying to solder but I was able to melt the existing solder and apply some new solder to make the joint secure once again. After that was able to reinstall the unit and the tv powered on without any problems."

That's exactly what I did to fix mine and my TV's been working like new!!!

Thanks again to Madhu and hope this will help fixing yours.

[Krankshaft]

Re: Samsung LN-S4041D Repaired - Finally

Watch out for those guys using General Purpose Radioshack caps on their sets really foolish. They are an unknown manufacturer and only 85C rated they will blow and fail again.

You need low ESR replacements in switching power supplies and they MUST be 105C rated. Just FYI.

Sometimes a little knowledge, a Ratshack soldering iron, and Ratshack GP caps can be dangerous .

Standard operating procedure to check for cold joints during a repair job. Even if you find bad components doesn't hurt to do a once over with a magnifier.

Good job on your set.

[rxchng]

Re: Samsung LN-S4041D Repaired - Finally

Here is the cold solder joint:

[Krankshaft]

Re: Samsung LN-S4041D Repaired - Finally

All because of the stupid EU lead solder ban.

Manufacturers still don't know how to use the lead free properly. Since a cloudy joint for lead free is normal bad joints can go unnoticed.

[Wizard]

Re: Samsung LN-S4041D Repaired - Finally

That eyelet crimp was oxidized prior to soldering wave caused this bad joint. Not the no-lead solder. I had this same issue OCCASIONALLY in other TVs but not in LCD inverters (regardless of solder type) except for two samsung LCDs with this which is very rare. We service over 100-120 LCDs a year. Just two with that. That's pretty good record especially with no-lead solder.

Cheers, Wizard

[crosswire]

Re: Samsung LN-S4041D Repaired - Finally

Hi all
I have been following a similar thread on another forum reg the bad caps
we replaced 4 capacitors on the board and the tv came back on and was on for the whole week ok. Now it has gone dark again with just audio. Actually it started with just one channel that had no video but just audio now its all channels.
I've read people swapping out the actual mother board etc and it worked
but maybe will check the cold solder and see if we have that too
any other advice?

[rxchng]

Re: Samsung LN-S4041D Repaired - Finally

Hi all
I have been following a similar thread on another forum reg the bad caps
we replaced 4 capacitors on the board and the tv came back on and was on for the whole week ok. Now it has gone dark again with just audio. Actually it started with just one channel that had no video but just audio now its all channels.
I've read people swapping out the actual mother board etc and it worked
but maybe will check the cold solder and see if we have that too
any other advice?

I would replace all caps with >1000uF. Then, check for cold solder joints. Good luck!

[TinSoldier]

Re: Samsung LN-S4041D Repaired - Finally

Same model TV, same problem, same solder joint.

I had originally bought the TV used a couple of months ago and the original problem was power up problem caused by the caps. I posted a picture of them in another thread.

The past week or two the screen has been going black but audio remained. And it was getting worse and worse.

Took the TV apart this morning and found the exact same solder joint on the inverter transformer broken. I resoldered both input connections. Seems to be okay, for now.

Thanks, rxchng, for blazing the path. And thanks, Badcaps.net for being such an excellent resource.

[shawn1]

Re: Samsung LN-S4041D Repaired - Finally

ok i have the same tv. no power at all. i opened the back and used a wire tester and noticed that the power stopped at the little fuse. so i replaced the fuse and as soon as i plugged the power cord in would blow the fuse immediately. what would cause this. is this the same problem

[Th3_uN1Qu3]

Re: Samsung LN-S4041D Repaired - Finally

If the fuse blows then obviously something is shorted downstream of that fuse. Check switching transistors, diodes, and so on.

[BottleCap]

Re: Samsung LN-S4041D Repaired - Finally

Just a noob here but I have the same TV and from what I've seen on the PCB and compared to the attached picture by rxchng it doesn't look to be cold solder joints to me. I see those as the extra metal of the pins for heat sinks and ground pins sticking through the PCB. I haven't actually removed one of the pins to confirm this but I'm pretty sure because they all seem to look the same. Of course I don't have a lot of experience with what cold solder joints look like so it could be a combination of both. I resoldered mine just in case but I'm pretty sure my solution was the bad caps I replaced.

Maybe if someone can desolder the pins that hold in the heat sinks then we could confirm this and it might help some other people in the future. I think those pins have some sort of extra metal tabs that help hold in the component while soldering.

[alick]

Re: Samsung LN-S4041D Repaired - Finally

ok I am having the same problem with this unit as well. it wont power on. when i plug it in the power goes click like it trying to power up and then it clicks off again but the red light on the front of the tv blinks 4 times.

I already replace 19 of the 20 caps on the board and still same thing. the only cap i ddint replaces is the that really big one in the center of the power board. there were 2 x 50v 1uf caps I replace with 63v 1uf caps. the guy at the store said it would me fine.


I just wondering if there is anything else i might have missed. i will check the solder joints again but they look fine when i check it last.

thanks in advance I didnt want to start a new thread so I figure i would add to this one.

Alick

[cashkennedy]

Re: Samsung LN-S4041D Repaired - Finally

Your problem sounds considerably different from the other people on this thread, since they didnt get any flashing lights. Your tv is actually identifying a problem and shutting off because of it, which usually means something like the inverter isnt able to power on / talk to the other inverter / start the bulbs.

You might want to measure the power leaving the power supply board which would for the most part eliminate any chance it was a problem with the power supply. You would check for the voltage on 5v wires, 24v, and something inbetwene 12-18, sometimes theyre marked clearly on the board. Once you get readings for all 3-4 voltages leaving the board post them here and people will tell you if they're normal.

[longfingaz]

Re: Samsung LN-S4041D Repaired - Finally

Like some of you, I replaced some bad caps but the black screen problem was still there. Then, I kept reading everything I could find on the internet and finally I found the culprit!

It has to do with "cold solder joint". Apparently it's common to several Samsung models. If replacing caps didn't solve your problem, this may help.

Thanks to Madhu from TECHREPORT forum (http://techreport.com/forums/viewtop...=a&start=390):

"After some testing I noticed that under the black housing on the left corner module there was some kind of buzzing noise like there was a short in the circuit. After inspecting underneath the power supply unit, I noticed that one of the soldering joints for the black unit above was cracked. So like everyone else I head to Rat Shack and picked up a 15/30 watt soldering iron and some rosin core solder. It was my first time trying to solder but I was able to melt the existing solder and apply some new solder to make the joint secure once again. After that was able to reinstall the unit and the tv powered on without any problems."

That's exactly what I did to fix mine and my TV's been working like new!!!

Thanks again to Madhu and hope this will help fixing yours.

Well , I found this in the trash.. and it worked, then shut off.. so i checked for bad caps.. had like 6 changed em all.. worked a lil better (i think) then i couldnt find anything.. it sat for the last couple months.. i just decided to google some more about it.. found this..

So i had the same bad solder joint.. I just resoldered.. Testing now.. will post in a bit if this solved my problem..

Thanks for putting up picture!

[zogtheobvious]

Re: Samsung LN-S4041D Repaired - Finally

https://www.badcaps.net/forum/images...bootyshake.gif

Thanks to this forum, my Samsung is once again King of the Living Room.

Replaced the caps on the power supply; no cold solder repair necessary.

You guys RAWK!

[budm]

Re: Samsung LN-S4041D Repaired - Finally

This kind of poor solder joints are in the monitors, TV, laptop DC input jacks, stereo, large through hole components such as transformer, power MOSFETS. ETC. mounted on the PCB.
One thing I always do it to inspect and resolder the bad looking joints, you can see small ring around the component leads.
http://s807.photobucket.com/albums/y...lder%20joints/

[rxchng]

Re: Samsung LN-S4041D Repaired - Finally

It's been a little over 3 years since I repaired my Samsung TV, guess what... it's happened again, audio fine but no video, just a black screen. After I flipped over the main PCB, I noticed the very same solder joint is now black! So, I re-did what I did 3 years ago, used desoldering wick and then new solder.. viola! Hopefully it will live another 3 years.

[capkid]

Re: Samsung LN-S4041D Repaired - Finally

Wow, thanks for reporting back three years later. It's interesting to see how long some of these repairs hold up.

[jpgasch]

Re: Samsung LN-S4041D Repaired - Finally

have to thank you...your pic was exactly what was wrong with the TV the solder was exactly the same shape

[102mm]

Re: Samsung LN-S4041D Repaired - Finally

Thank You Everyone!! This thread has helped me fix TWO TVs with that problem!! This site is the best!!!