Samsung Changing Vertical Color Bands Lines LN46A540

[SteveTheBeave]

This Samsung has bands that change color. The overall banding remains the same width. Sometimes they fade in and out and the picture is fine. If you notice, the bands start from the center but do not go all the way to the left edge.

The bands show up in front of the menu on all inputs.

I tried reseating the flex cables to the TCON board. None of the caps seem to be bulging on the power supply.

Not sure if it is a failure with some TABs or a bad board somewhere. Any help would be appreciated.

[tom66]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

On a similar LE40A656 TV, with a similar fault, it turned out to be T-con.

However I have figured out a way of eliminating the main board, which can rarely cause this fault.

Connect a working video source with colour to the display and select the right input.

Turn the TV off and get it into standby mode.

Press Info, Menu, Mute and then Power on the remote control.

This will bring up the service menu.

It may be difficult to see but try and access the Advanced menu.

Go to "LVDS" or "LVDS type". Change the type. The screen colours should change. If the coloured bands appear to alter their appearance too (use your judgement - do they appear to change as before with different video sources, or do they completely change counter to what you would expect), it is probably a main board issue. If not, it is probably a T-con board or panel issue - isolating which one is tricky, but panel failures often involve a dim/slow picture on parts, or a few isolated vertical lines, not a general area failure.

Change back the type until the picture colours restore.

It may be possible to get the TV to output the display on one of the SCART ports - so you can display it on another display for accessing the service menu.

[SteveTheBeave]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

Thanks, Tom.

I will try that when I get home.

So, in your experience, a general failure of that size probably won't be due to a bad panel or maybe a TAB bonding issue?

I'm hoping that it is just the TCON. I can get a replacement here for about US$37.

[tom66]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

Thanks, Tom.

I will try that when I get home.

So, in your experience, a general failure of that size probably won't be due to a bad panel or maybe a TAB bonding issue?

I'm hoping that it is just the TCON. I can get a replacement here for about US$37.

Usually a tab bond failure would cause either one or a couple vertical lines, or a slow/dim/distorted picture on one half or all of the display. You have something which is more like digital noise.

What is the part # of your T-con? It may be possible to get it cheaper.

[SteveTheBeave]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

When I powered up to get into the service menu, there were no bands (see pic). It seemed to be working just fine. The same thing happened yesterday, but the bands reappeared after about an hour and started changing colors again.

I did what you suggested and found the LVDS menu and figured out that part. If it happens again, I am ready to test for the main board.

In the mean time, I am going to get the number off of the TCON...

[SteveTheBeave]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

Got the TCON out. Not sure which of the numbers you need, sticker or etched (see pic).

I searched for the FHD number and found a bunch of used ones. Seems a bit daft to purchase a used one.

Please let me know if you know of a source for a cheaper one.

Thanks again for your help and advice.

[SteveTheBeave]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

Just changed out the TCON board and no help.

I also tested the LVDS and no color change on the bands when I changed the options.

I want to eliminate the panel before I toss the whole TV.

I think my last two options are the cables from the TCON, or the board that the two flex cables from the TCON attach to. What are the two boards that the TCON attaches to at the top of the TV?

One side note, I also noticed that the bands change color to whatever the color scheme on the good part of the picture is. I thought it was just random at first.

Thanks.

[SteveTheBeave]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

And one more note is that the block of bands come and go. The full picture is fine most of the time, but occasionally the bands with fade in with interference. It is not a sudden on/off situation. Thanks.

[tom66]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

Just changed out the TCON board and no help.

I also tested the LVDS and no color change on the bands when I changed the options.

I want to eliminate the panel before I toss the whole TV.

I think my last two options are the cables from the TCON, or the board that the two flex cables from the TCON attach to. What are the two boards that the TCON attaches to at the top of the TV?

Hmm. Bad luck...

Did you try the LVDS trick to try and eliminate the main board?

The top boards are the panel driver boards and are non-replaceable as they are bonded straight to the screen

[SteveTheBeave]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

The main board tested out fine like you said using the LVDS settings.

Looks like it is the panel.

Thanks for all the info.

[tom66]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

That sucks .

[tibimakai]

Re: Samsung Changing Vertical Color Bands Lines LN46A540

What did you end up doing with this issue?