Backlight, Sound, No picture, UN75J6300

[rustytierod]

I've got no picture, but sound on a UN75J6300, Backlight are clearly working.

I looked for test points on the Tcon but don't see voltage markings nearby, the service manual was of no help either. No change with Tcon disconnected, main processor heatsink on that board is hot. I understand led driver is part of main board.

??

[CapLeaker]

Re: Backlight, Sound, No picture, UN75J6300

Check the LVDS on the main board with an oscilloscope, while turning on and off the menu of the tv all the time. Check each pair on the LVDS. If you don't see any action, the main board needs to be replaced. If you do see action on the o'scope, the TCon is bad.

Also: There are 2 ribbon cables from the TCon to the panel. Unhook one of them, turn the TV on and see if you get half of a picture. Then try the other side.
As usual: PIC's please!

[Davi.p]

Re: Backlight, Sound, No picture, UN75J6300

Get a hires picture of the tcon especially those from shopjimmy site.

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

Well I replaced the tcon and no change.

I also unplugged one ribbon to panel and nothing happened. Screen remained black. Even if the main was bad wouldn't I see something when unplugging one of them?

[dskall]

Re: Backlight, Sound, No picture, UN75J6300

Need picture of t-con. Do you have voltage to t-con?

[Davi.p]

Re: Backlight, Sound, No picture, UN75J6300

Is there an FRC card?

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

The heat sink is pretty hot on the tcon. Sorry hard to get pics of this beast. There is a small Crack in the top corner,, could that have rendered panel bad!

[Davi.p]

Re: Backlight, Sound, No picture, UN75J6300

Crack in the glass? I think with that crack you must at least see vertical bars..

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

No FRC card on this model. Don't have oscilloscope. I get a bunch of 3.2V readings on the tcon, so I know it's getting something. Even tried manipulating tab bonds to no avail. I guess it's the main. ..

[Davi.p]

Re: Backlight, Sound, No picture, UN75J6300

The crack is on the panel glass??

[CapLeaker]

Re: Backlight, Sound, No picture, UN75J6300

a crack in the LCD does not make the main board fail.

[Davi.p]

Re: Backlight, Sound, No picture, UN75J6300

Check 12vin on the tcon.

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

Replaced tcon and main board, still no picture only sound

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

UH01 and TH01 just realized there are two versions of this board. Does it really make a difference?

[budm]

Re: Backlight, Sound, No picture, UN75J6300

But we still do not know if you have 12V feeding the T-CON board or not.

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

Ok

[Davi.p]

Re: Backlight, Sound, No picture, UN75J6300

I'm sorry don't check 12v in, 'cause processor is hot.. even with a crack on a corner you must see at least the other side half. Is there any chip on the panel's boards? Can be at short. You must measure tcon voltages. but whitout a picture i can't point it.

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

Yes 12v on the fuse both sides. Could melt butter in short order on replacement tcon heatsink as well. Sounds like panel ics.

[Davi.p]

Re: Backlight, Sound, No picture, UN75J6300

I think you can't access to the panel's boards due to the size of the screen right? Anyway i think a 75" needs an accurate measurement of the common tensions just to be sure replacement tcon is good, with the heatsink i surely can't point you where to measure..

[rustytierod]

Re: Backlight, Sound, No picture, UN75J6300

No, you can get to the panel ics quite easily. Tcon gets hot pretty quick, would it be possible to measure before cooking it?