Samsung UN46D6003SFXZA screen dark then bright

[aasnowskate]

I have a Samsung 46in LED TV M# UN46D6003SFXZA. The screen goes from bright to dark and back and forth. The backlights do not seem to be dimming at all when you stand behind the TV. The voltages from the power supply to the backlight do not change when it goes dark. The picture kind of looks like it is flooded with red.
Has anyone had this happen? I went into the servicer menu and reset the factory settings and this did not help. I am leaning toward the main board being the problem.
I will post pics of the boards shortly.

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

here are the pics of the boards and the difference between when the picture is bright and dark.

[tom66]

Re: Samsung UN46D6003SFXZA screen dark then bright

Hard to tell - Can you see what a "black" image looks like on the panel to see if the backlights drop out.

[stj]

Re: Samsung UN46D6003SFXZA screen dark then bright

i think your losing some blue bits - maybe a bad buffer ram or bad soldering on the scaler chip.

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

I put the TV on channel 3, which is a blank or black screen and then after a few seconds it goes to a snowy picture. The screen is black and the backlights get really dim and when it goes to snow, the backlights light back up to full brightness.
The backlights do not dim like this when there is a picture and the picture goes dark.

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

I am assuming that the buffer ram and scaler chip are on the main board?

[stj]

Re: Samsung UN46D6003SFXZA screen dark then bright

they are.
scaler chips often get *very* hot and should have a heatsink stuck on them - but often they dont bother to save money!

[tom66]

Re: Samsung UN46D6003SFXZA screen dark then bright

First I think check the backlights, but if they don't dim you can check the scaler from the service menu.

Just put TV into standby and press Mute, 1, 8, 2 then power it on.

Then access Control > Test Pattern

there should be about 3 generators there which lets you narrow it down to T-con/Panel or main board.

Personally with knowing how bad the early panel failures are on Samsung D-series TVs I'd be thinking panel :/ for your sake I hope not!

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

I can not find a test pattern under the control in the service menu.

[tom66]

Re: Samsung UN46D6003SFXZA screen dark then bright

Can you show a picture of what you've got instead? I'm using what I did on a B-series LED as reference.

edit: page 3 bottom right, try that

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

here is the pic of the menu and then the next menu when control is selected.

[tom66]

Re: Samsung UN46D6003SFXZA screen dark then bright

See my edit.

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

I went through all the test patterns and they looked fine, but the screen was still darkening and brightening the same while going through the tests.

[tom66]

Re: Samsung UN46D6003SFXZA screen dark then bright

So you will need to check the backlight for us. Any BLACK test pattern? Turn all lights out. If the black level (the slight blue or grey glow from the panel) varies, then the backlights are causing your problem...
If not... it is the panel or T-con.

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

With the black test screen, the backlights do not vary at all. The test indicator display in the upper left corner of the screen brightens and darckens, but the screen and the backlights (when I stand behind the TV) do not vary at all.

[tom66]

Re: Samsung UN46D6003SFXZA screen dark then bright

Well, then, it is a crap-shoot between T-con and panel.
I would say panel has a fair chance, due to tab bond fault.

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

After all the tests, I am thinking the same thing. I might play around with the tab bonds and see if I can make it act up by pressuring them, but this is the 3rd Samsung that has had a bad panel due to those tab bonds being on the bottom of the set.
Thanks for the help. If I order the T con, I will post my findings.

[aasnowskate]

Re: Samsung UN46D6003SFXZA screen dark then bright

I ordered the T con from ebay and it fixed the problem. Thanks again Tom66 for the help. I was thinking bad panel tab bonds, but when I pushed and lightly stressed them, the pic did not change. When I sprayed some freeze spray on the T con board, the pic would change. That helped me think it would be the T con. All fixed up now.

[tom66]

Re: Samsung UN46D6003SFXZA screen dark then bright

That's nice to hear you got a solution in the end. I am surprised!

[tibimakai]

Re: Samsung UN46D6003SFXZA screen dark then bright

Maybe next time it will be the panel. I wouldn't keep a D series.