Samsung LN-S3251D

[Sam I Am]

Hello All...
I have been lurking for some time, trying to learn the ins and outs of circuit repair. My latest "project" is a 32" Samsung TV that I intend on hanging on the bedroom wall. I have replaced all of the caps with the exception of the rather large one. Replacement caps were either Panasonic FM/FC, Rubycon MCZ, or Nichicon HV, mostly Panny's. The problem I am having appears to be video related but I'm unsure. Upon initial power up, the display shows wide horizontal gray/black lines, then blank, then momentarily solid blue, then finally what you see in the below pic. At this point, the set shows the channel in the upper left corner then starts searching for a signal. With the satellite cable attached, the set still shows no signal detected. Any ideas on my next troubleshooting step(s) or a definitive diagnosis would be greatly appreciated.

[PlainBill]

Re: Samsung LN-S3251D

Hello All...
I have been lurking for some time, trying to learn the ins and outs of circuit repair. My latest "project" is a 32" Samsung TV that I intend on hanging on the bedroom wall. I have replaced all of the caps with the exception of the rather large one. Replacement caps were either Panasonic FM/FC, Rubycon MCZ, or Nichicon HV, mostly Panny's. The problem I am having appears to be video related but I'm unsure. Upon initial power up, the display shows wide horizontal gray/black lines, then blank, then momentarily solid blue, then finally what you see in the below pic. At this point, the set shows the channel in the upper left corner then starts searching for a signal. With the satellite cable attached, the set still shows no signal detected. Any ideas on my next troubleshooting step(s) or a definitive diagnosis would be greatly appreciated.

OK, the OSD is working. "Satellite cable' is ambiguous. Do you mean HDMI cable? Have you tried hooking it up to an antenna and having it scan for signals? How about selecting other inputs (composite or component)?

PlainBill

[Sam I Am]

Re: Samsung LN-S3251D

Thanks for the reply PlainBill.
"Satellite cable" means the cable directly from the Dish Network receiver to the set.
Just got off the phone with Dish tech support and got the feed straightened out from the receiver. The install guys had replaced the receiver a few months back and didn't properly configure the second feed. I now have a picture, albeit a stripped one.
Any ideas?

[PlainBill]

Re: Samsung LN-S3251D

Thanks for the reply PlainBill.
"Satellite cable" means the cable directly from the Dish Network receiver to the set.
Just got off the phone with Dish tech support and got the feed straightened out from the receiver. The install guys had replaced the receiver a few months back and didn't properly configure the second feed. I now have a picture, albeit a stripped one.
Any ideas?

The picture doesn't tell me anything. The first step in troubleshooting is to see f the problem is confined to one input, or appears an several different inputs - tuner, HDMI, and composite would indicate it is either the output stage of the main board or the t-con.

PlainBill

[Sam I Am]

Re: Samsung LN-S3251D

Okay... Sat. signal (tuner) works, Composite video works, don't have any HDMI equipment, yet. Set shows wide grainy black/grey horizontal stripes throughout the image being shown. I can check the RGB input later if need be but I suspect it will probably look like the rest. Also noticed that while switching between inputs (DVD to tuner and back) that the image is momentarily perfect then goes all grainy horizontal stripes.

Sam

[Sam I Am]

Re: Samsung LN-S3251D

Oops... RGB should be VGA (PC).
All these acronyms get confusing at times.

[PlainBill]

Re: Samsung LN-S3251D

Okay... Sat. signal (tuner) works, Composite video works, don't have any HDMI equipment, yet. Set shows wide grainy black/grey horizontal stripes throughout the image being shown. I can check the RGB input later if need be but I suspect it will probably look like the rest. Also noticed that while switching between inputs (DVD to tuner and back) that the image is momentarily perfect then goes all grainy horizontal stripes.

Sam

That SHOULD be telling us something. But for the life of me, I can't figure out why changing the input would momentarily cause the picture to clear up.

PlainBill

[tmwalsh]

Re: Samsung LN-S3251D

I need to see a picture.
If "wide grainy black/grey horizontal stripes throughout the image being shown" mean there is a picture overlaid with stripes, that is one thing. If it is totally made up of stripes with no recognizable picture, that is another.
Is the bluish-green thumbnail above what you get now after a second or so of regular picture?
I'm confused, but that's nothing new.
tom

[Sam I Am]

Re: Samsung LN-S3251D

Will post a pic later on this afternoon as I am presently at work.
Thank you for the reply.

Sam

[Sam I Am]

Re: Samsung LN-S3251D

Okay... here is the latest pic on the current state of this set.

Sam

[Sam I Am]

Re: Samsung LN-S3251D

So far I've confirmed that this set shows stripped somewhat horizontal lines regardless of a signal. The screen should be a solid blue field without any inputs attached or a clean image viewing through any inputs. My initial concern, until I got thoroughly sidetracked about image production, was the appearance of the "stripes" after power up. This set will now consistently show a momentary solid blue screen upon power up. The stripes will show up lightly at first (clear areas between the scrambled pixels) and get progressively worse until the whole screen is filled. It looks like the pixels are totally "confused" for lack of a proper term. In addition, I have noticed that whenever an OSD is pulled up (such as volume) the volume level number can be seen spaced repeatedly throughout the bottom of the stripes. Also, the set must be off for approx. 15 - 20 seconds for repeatability. Does anyone have a clue about this problem?

[PlainBill]

Re: Samsung LN-S3251D

So far I've confirmed that this set shows stripped somewhat horizontal lines regardless of a signal. The screen should be a solid blue field without any inputs attached or a clean image viewing through any inputs. My initial concern, until I got thoroughly sidetracked about image production, was the appearance of the "stripes" after power up. This set will now consistently show a momentary solid blue screen upon power up. The stripes will show up lightly at first (clear areas between the scrambled pixels) and get progressively worse until the whole screen is filled. It looks like the pixels are totally "confused" for lack of a proper term. In addition, I have noticed that whenever an OSD is pulled up (such as volume) the volume level number can be seen spaced repeatedly throughout the bottom of the stripes. Also, the set must be off for approx. 15 - 20 seconds for repeatability. Does anyone have a clue about this problem?

I'm tempted to say T-Con, but I don't have a lot of confidence in that. Wizard knows far more than I do about this.

PlainBill

[Sam I Am]

Re: Samsung LN-S3251D

Well.... hopefully he will cast an eye over this way and impart some wisdom.

[el3ctroded]

Re: Samsung LN-S3251D

Does it get better/worse/stay same over time?

Use a fan to cool areas. Any difference?

Was this the original problem with the screen? If not, what did it do in the beginning?

[Sam I Am]

Re: Samsung LN-S3251D

It pretty much stays the same after about 30 seconds run time. As a side note, I have been running this unit with the back cover removed to facilitate troubleshooting. The screen has been doing this since it was received (fairly good deal) figuring it would be a relatively inexpensive fix. It appears to be turning out otherwise.

[el3ctroded]

Re: Samsung LN-S3251D

How does it change during those 1st 30 seconds?

[Sam I Am]

Re: Samsung LN-S3251D

The clearer spaces between the "snowy" lines will eventually become "snowy" themselves (see pic @ post 10).

[el3ctroded]

Re: Samsung LN-S3251D

So it gets worse as the set warms up. I'd play with cooling: Cool specific areas one at a time to see if any location changes the amount of time it takes before it gets to it's worst fuzzy state.

[Wizard]

Re: Samsung LN-S3251D

Noisy linear regulator, you have to find it with your scope.

Cheers, Wizard

[Sam I Am]

Re: Samsung LN-S3251D

Is the "linear regulator" the same as an LDO? Is it generally located on the power board with the caps or some other board? I'm going to take a stab in the dark and "assume" this component is attached to an aluminum heat-sink. If this is the case, then I have a grand total of 10 components to choose from. A schematic sure would be sweet.