LG 37LC2D No picture, believe bad power supply

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

In which case, it would be a good idea to look at the t-con board next. Can we get a picture of that? The fault is most likely on the t-con or main board.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

I think that if fault will be on T-con TV should work ok like sound, channel choosing, scart input etc??

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

Yes, normally.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

Ok so what could be bad on motherboard.. I already checked all voltage regulators and do to numbers on it there is all voltage outputs ok.

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

The processor could be bad, or there could be a bad capacitor causing too much ripple in a certain area. Have you ever managed to get TV to work, perhaps intermittently, or did it fail suddenly?

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

my friend bring it to me... tv was freezing and sometimes suddenly go blackscreen etc.. he said that he replaced that 16V 1000uF cap (as was said here) that was bulging and then he said that TV was working fain... he let it play around 2 houres and then he said that was blackscreen again....
so he bring it to me I plug it power up and it show only that lines as i take photo... nothing else since that... so I found that +3,4V is low around +2,4V so I though that is the problem.... so I ordered new controller for that two mosfets...
But I want to try it before replacement will come so I injected +3,4V externally and nothing changed still only lines.. freezed and no sound

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

Try using a hairdryer or other focused heat source on the main board. If you find something that works when heated, there is probably a problem there.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

heh yeah I tried that... even heat whole board on my BGA machine nothing changed

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

Perhaps freeze spray then?

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

I tried power up TV firstly in my cool room.. around 12°C and nothing changed... Still half screen black, half screen colored vertical lines.

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

You may be looking at T-con or panel fault then; perhaps the input selector doesn't work as you expect or the sound is muted. I've had that happen to me before.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

so how can I test if t-con has good signals from motherboard

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

You would need an oscilloscope to do that.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

yes I have it

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

Can I see a closer up shot around the connector which goes from the main board to the T-con - the LVDS cable.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

here it is

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

I was hoping to be able to see the differential pairs but it looks like they are not easily visible on the main board. Can we get a picture of the T-con then?

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

I have got some news.. after little play with remote control that friend bring me today i have sound working from external scart dvd player. So the problem really will be display or T-con isnt it?

Still have color lines on half display but sound works ok.

[tom66]

Re: LG 37LC2D No picture, believe bad power supply

Most likely. It is rare for a main board to fail to output video but give audio, it can happen but it is rare.

[godzzila]

Re: LG 37LC2D No picture, believe bad power supply

So today I received controllers for 3,4V.. I replaced and NO CHANGE!!! Rail is still low 2,7V!! So thats not a problem with controller of that two mosfets!!

And another problem that lines I still have...