Samsung LE40M87bdx picture problem

[vagos_89]

Hello all and sorry for my english. I have the tv above and the problem is that when i open the tv i hane no picture at all. The half picture is blue and the other is black and gradually in seconds go to black. The sound play without problem. When i coonect via vga or hdmi cable i have picture but with vertical lines in the left and some black shadows.

I measured the voltages of power suply and are 5.6V(i think is good) and for 12 and 13V i have both 11,5V. I replace the electrolytics capacitors in the psu output but didnt change anything. I see from the schematic that the 13V goes to the inverter board which is working fine, the lamps goes on and stay on altough the 13V are 11,5V to my measurement.

Also i must say than i replaced the t-con board of the tv and the problem remains exactly the same as before. i thought to buy another mainboard(AVboard) but because is a little expensive i would like to be sure where is the broblem before i buy.

So, could anyone help me? Is possible to have psu or panel issue or my problem is in the mainboard? Thanks in advance!

[vinceroger69]

Re: Samsung LE40M87bdx picture problem

sounds like a bad lcd panel too me but i guess it maybe a faulty mainboard lets see what the others have too say

[vagos_89]

Re: Samsung LE40M87bdx picture problem

Is it possible to be lcd panel problem and when i conect vga or hdmi the picture is "clear" with lines and when i conect the TV source the picture is completely black? If its the panel the picture should not be the same in both cases?

[ReeceyBurger123]

Re: Samsung LE40M87bdx picture problem

Need images of fault.

[vagos_89]

Re: Samsung LE40M87bdx picture problem

The first picture is with vga, the second with hdmi, the third with AV conection.
With the tv tuner as i say i have a half picture blue and in seconds goes and stay to black, only sound play.
Sometimes when i change the source stays an idol behind from previous source for few seconds. Is tha possible to be faulty panel?

[dick_barton]

Re: Samsung LE40M87bdx picture problem

When using the AV input (photo 3) does the picture on screen remain clear of lines and display correctly when playing.

[vagos_89]

Re: Samsung LE40M87bdx picture problem

When i connect the AV the picture have some black shadows but for a few seconds only, therln clear and its ok. But only in AV mode.

[dick_barton]

Re: Samsung LE40M87bdx picture problem

I would have thought that if you have a decent picture when connected through the AV input that it would be a mainboard problem. Best to see what others think.

[vagos_89]

Re: Samsung LE40M87bdx picture problem

Also if i try without source. I have black picture in the tuner mode again. And to hdmi, vga the picture is blue with vertical lines. I don't know sometimes i can see shadow idols from previous source that remains to the picture for a while when i change the source and make me wonder that there is a possibility to be lcd panel problem.

[ReeceyBurger123]

Re: Samsung LE40M87bdx picture problem

I say mainboard the boards used in this set are prone to failure.

[vinceroger69]

Re: Samsung LE40M87bdx picture problem

what is the mainboard part number

[vagos_89]

Re: Samsung LE40M87bdx picture problem

Thanks all for.your replies. So you suggest me to try to replace the mainboard? Is sure that the panel is ok? The mainboard is BN94-01490A

[vinceroger69]

Re: Samsung LE40M87bdx picture problem

No one can be sure the panels ok but the signs are showing a possible mainboard issue another sign it maybe is a mainboard issue is that after a quick search i cant find any for sale in stock so this board may have a high failure rate.

[vagos_89]

Re: Samsung LE40M87bdx picture problem

Thanks! So i think to risk and replace the mainboard. Is threre any way to can test if is lcd panel or i should try to replace mainboard and see if the problem solve?