LG 37LC2D No picture, believe bad power supply

[godzzila]

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

Anyone can help please

[tom66]

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

I do not know then what the problem is, but I can suggest a work-around. That is to use one of these modules:
http://www.ebay.co.uk/itm/LM2596-DC-...item1e79c56663

You can rig it up to output 3.4V from e.g. the 12V or 24V rail.

[godzzila]

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

ok thanks... but I still have to fix that lines problem.. so I will assembly whole tv and check LVDS signals on T-con.§
If I have sound ok but on screen half black and half lines its not related to low 3,4V rail even when i boost it with external power supply to 3,4V ok. So?

[tom66]

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

The 3.4V may power some video processing on your model, so maybe it could cause the lines on the screen, you really cannot know until you get the outputs from the power supply stable.

[godzzila]

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

So the injected external 3,4V it doesnt to be 100% ok? It looks stable and ok real 3,4V I tested with multimeter for proove.

[tom66]

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

Oh, I didn't realise you did that, it's been a long time. That would seem to indicate LCD/t-con fault.

[godzzila]

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

finaly have got screen working ok looks like there was some humidity that cause problem on screen (friend bring it to me in rainy day only TV in towel)

ok.. so I have picture and sound working ok, but the first problem is still there, HDMI, RGB (VGA) inputs are not working.. TV show no signal only.

scart and analog, and TV antenne works ok picture and sound....

With 3,4V injected and working ok no change still HDMI and RGB no signal.

[tom66]

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

Can you supply a picture of your main board?

[godzzila]

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

http://flattvparts.co.uk/bmz_cache/d...ge.530x520.jpg

bigger http://flattvparts.co.uk/bmz_cache/4...e.1000x982.jpg

i will do better later

[tom66]

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

There are voltage regulators on there, have you tested any?

[godzzila]

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

yes tested all are ok

[tom66]

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

Including the 5 pin ones?

[godzzila]

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

didnt test that ones yet.. which should i test first.. i think that I need search for datasheet on each for verifie?

[tom66]

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

Yes, just read the numbers off and search for them, or post them here and we will look for datasheet.

[godzzila]

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

all 5 pin regulators and stabilizators work ok checked good acording to datasheets

[godzzila]

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

All works ok except RGB and HDMI... TV says NO SIGNAL on these inputs.
RGB go to VCT-IP directly and HDMI go to AD9381 and then to VCT-IP.
VCT-IP is a main one with small heatsink...

So how can I check VCT-IP if its bad?

[tom66]

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

VCT-IP looks to drive the LCD panel; it is unlikely that it is bad on two inputs but nothing else, since it is still driving the LCD properly.

[godzzila]

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

Yes its main video chip as well as drive audio too. So what could be bad? No RGB and no HDMI.

[tom66]

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

I am still wondering if there is some software or EEPROM problem. I am sorry but I can't offer much advice on how to narrow it down further.

[godzzila]

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

Problem was that TV was freezing on RGB input after some time... so it was working but freezing I think that because low 3,4V rail.. so the friend bring it to me but I had a problem with screen lines and no picture (because moisture)... and now TV not work on RGB or HDMI... -> NO SIGNAL

So may be ICs (or something else WHAT?) become damaged because low 3,4V rail?... If I inject 3,4V and got it stable nothing changed still no signal.