Samsung 59" Plasma 3D Blank Screen

[tom66]

Re: Samsung 59" Plasma 3D Blank Screen

Its not the solution unfortunately It was great all day, however I left it on overnight and woke up to a blank screen. I will just get a new board for it.. so there is no harm done by putting it in the oven for half an hour at 250C unlss it blows my oven up..

Do you mind shipping the board to me? Would be good to see if I could reball the BGA (then you could get a Freeview board, not satellite.)

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

Damn, thats a great offer and I would have taken it up.. however 20 minutes at 250C has just destroyed it lol.. it is just doing exactly what it did before, won't display anything on the screen and buttons are unresponsive, all voltages are still okay and chips are getting warm though, do you think it is still repairable by a reball? You are more than welcome to take the board off me anyway!

Regards

[tom66]

Re: Samsung 59" Plasma 3D Blank Screen

Damn, thats a great offer and I would have taken it up.. however 20 minutes at 250C has just destroyed it lol.. it is just doing exactly what it did before, won't display anything on the screen and buttons are unresponsive, all voltages are still okay and chips are getting warm though, do you think it is still repairable by a reball? You are more than welcome to take the board off me anyway!

Regards

I'll give it a go.

Never done it before, but I do have the equipment to do it.

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

I'll give it a go.

Never done it before, but I do have the equipment to do it.

That is cool, I don't really know a lot about reballing, but don't you require the correct stencils??

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

Hmm... I am pretty confused as to what has happened to it while it was in the oven the last time. It doesn't work, but again it is back to square one. The chips are getting hot, all voltages are as they should be on the VR's and other components.. If I damaged a processor in any way, would it still get hot? It seems like the oven only destroyed the dry joints.. is that even possible??

Regards

[tom66]

Re: Samsung 59" Plasma 3D Blank Screen

Hmm... I am pretty confused as to what has happened to it while it was in the oven the last time. It doesn't work, but again it is back to square one. The chips are getting hot, all voltages are as they should be on the VR's and other components.. If I damaged a processor in any way, would it still get hot? It seems like the oven only destroyed the dry joints.. is that even possible??

Regards

Yes. The joints can crack completely and then no amount of reflow will fix it.

You're right about the stencils. I will need to find what stencil matches the package - the package should be standard though.

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

Well you are more than welcome to take the board off me would it help if I gave you the models of the processors first so you can determine if you can?

Regards

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

Is a stencil really required though? how hard would it be to remove the chip, remove all the soldier from the holes, carefully place soldier balls in the holes and then melt the chip back on?

[tom66]

Re: Samsung 59" Plasma 3D Blank Screen

Well you are more than welcome to take the board off me would it help if I gave you the models of the processors first so you can determine if you can?

Regards

Unfortunately it's most likely a proprietary processor, with no information available.

Is a stencil really required though? how hard would it be to remove the chip, remove all the soldier from the holes, carefully place soldier balls in the holes and then melt the chip back on?

Yeah, a stencil is most likely required. What has happened is one of the little solder balls on the bottom of the chip has broken. I'd have to remove this one and replace it.

Watch how to reball a BGA: http://www.youtube.com/watch?v=97nxZwHG5bA

Since I won't be able to get a stencil, I probably won't be able to do it, but I can give it a shot.

What might be possible is for me to remove the Freeview tuner module, so you could solder it on in place of the satellite module. Looks like it is just soldered onto the board.

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

Hi Tom, just been playing around with the board, I left it on for about an hour. The CPU is hot, I do not think there is a problem there, but the GPU is cold (are these actually what they are? - just an educated guess). I did some voltage checks around the GPU, if you look at the picture attached, all the bits and bobs in the red circle have a voltage, all the bits in the yellow circles are 0.. so I am assuming the GPU is where some dry joints are occurring.. or its now dead. It is weird though - The CPU gets much hotter than the GPU, when the TV was working I kept an eye on the temperatures, the GPU was not very hot, certainly not hot enough to cause problems..

http://tinypic.com/r/e7eygz/5

[tom66]

Re: Samsung 59" Plasma 3D Blank Screen

Hi Tom, just been playing around with the board, I left it on for about an hour. The CPU is hot, I do not think there is a problem there, but the GPU is cold (are these actually what they are? - just an educated guess). I did some voltage checks around the GPU, if you look at the picture attached, all the bits and bobs in the red circle have a voltage, all the bits in the yellow circles are 0.. so I am assuming the GPU is where some dry joints are occurring.. or its now dead. It is weird though - The CPU gets much hotter than the GPU, when the TV was working I kept an eye on the temperatures, the GPU was not very hot, certainly not hot enough to cause problems..

http://tinypic.com/r/e7eygz/5

GPU is probably overkill, but close enough. It looks like it just controls the display. It might be a scaler, for resizing the image, it might decode video... whatever it does is very important.

I'm not sure what solder ball is breaking, but maybe it's something important, such as the output enable, automatic warranty voiding system, or clock. It's clear the CPU is communicating with the GPU, but the GPU is dead. In the case of that video I linked, only one ball was broken, but all were reflowed to fix the problem.

I think these TVs run Linux, so the CPU is pretty powerful (600 MHz ARM from a 42" Samsung, probably more powerful in your model.)

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

Well, I just tried to fix it again, used a flux pen completely cover underneath the chip until it was dripping out the other side, then used a heat gun until the flux stopped bubbling and then let it cool down.. still nothing I thought that would have worked to be honest, maybe I have just ruined the chip?

Regards

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

This is crazy actually, now the chip is getting hot, and there are voltages on MOST of the bits in the yellow circles?! Maybe i should try it again.. it looks like its getting closer haha

[tom66]

Re: Samsung 59" Plasma 3D Blank Screen

Well, I just tried to fix it again, used a flux pen completely cover underneath the chip until it was dripping out the other side, then used a heat gun until the flux stopped bubbling and then let it cool down.. still nothing I thought that would have worked to be honest, maybe I have just ruined the chip?

Regards

The chip is probably fine. But the joints under the chip are almost certainly shot. No further heating can really fix it, especially not permanently. I would say you should save up for the US board and consider changing the module if it is just soldered on. You could also buy a Freeview HD box I have seen them going for only about £20 each.

[tom66]

Re: Samsung 59" Plasma 3D Blank Screen

This is crazy actually, now the chip is getting hot, and there are voltages on MOST of the bits in the yellow circles?! Maybe i should try it again.. it looks like its getting closer haha

Maybe more than one joint is broken, and they are intermittent.

[graham01]

Re: Samsung 59" Plasma 3D Blank Screen

Well you can certainly use this board as a test piece if you want but don't worry too much about damaging it.. By the way the CPU is 26x26 pins outer and the smaller GPU is 22x22 pins outer. Obviously I don't know the inside geometry but I'm guessing if you have a stencil of those sizes you can just fill the necessary holes? Anyway, I think you will have more luck doing that than removing the tuner module, there are also a lot of surface mounted components around it that do not appear to be on the cable board.

Regards