LG 70UH6350 (UB.BUSMLJr)

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

(!*&@(*!&!#!!

This TV is from hell

Replaced mainboard again and exactly the same Only difference is now only sometimes Toslink light goes on but I think I had this also with other board (seemed random.)

((

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

(!*&@(*!&!#!!

This TV is from hell

Replaced mainboard again and exactly the same Only difference is now only sometimes Toslink light goes on but I think I had this also with other board (seemed random.)

((

I'm thinking if these have a high failure rate and the 3 I have bought so far are like "last 1 in stock," maybe I keep getting bad ones? Like we have seen the backlight and all pixels light up so impossible to be something else? I will double check all voltages @ mainboard side.

[Computeman]

Re: LG 70UH6350 (UB.BUSMLJr)

Shorted TFT display

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

Shorted TFT display

Hey CM. I just saw your backlight tester post then this edit.

Have you seen the pics I posted though where I am able to lightup all pixels (1/2 screen at a time?) Wouldn't that be not possible if a short? Also DIAH's panel ribbon disconnecting tests...

Also shouldn't mainboard boot properly (ie. PC seeing the HDMI, maybe ethernet port working?)


A

[Diah]

Re: LG 70UH6350 (UB.BUSMLJr)

nothings impossible... but since now replacment MB under hand. please do the following
Remove Load...
1- disconnect all 4 ribbon between T-CON & LCD from T-CON side and never connect them again until you finish trouble shooting
2- same to WIFI /BT Module disconnect them

3-put yours DMM Probe always on T-CON Fuse F1 to remark the 12V

4- Insert USB pen with any kind of media content at any USB Port. prefer with LED Indicator to know if it blinking during start ( we need to know the DC-DC Circuit on MB produce USB 5V.

4- Plug the tv in wall socket. at time TV start (Toslink light goes on ) plug the TV from wall socket.. and never use the RC AGAIN::: to make us sure the MB registered the Last state mode ( mean always when you plug it at wall will start.. an not goes to STB )

5- please record movie on yours MB during this test and upload it here.. and tell the result about T-CON 12V.

[nomoresonys]

Re: LG 70UH6350 (UB.BUSMLJr)

cant remember if did this test, did you get a solid toslink light with any of the mainboards, with the cable from mainboard to panel unhooked, unhook it at the mainboard, less chance of any cable ends accidentally shorting out with incidental metal contact.

[nomoresonys]

Re: LG 70UH6350 (UB.BUSMLJr)

still makes me wonder if maybe at least one of those mainboards are good and something else is wrong??

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

cant remember if did this test, did you get a solid toslink light with any of the mainboards, with the cable from mainboard to panel unhooked, unhook it at the mainboard, less chance of any cable ends accidentally shorting out with incidental metal contact.

1 board yes Toslink goes solid reliably when using remote standby > on.

Latest board seems to only occasionally have Toslink go on when switching out of standby.

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

I need a headmount camera or something, too hard to film with one hand but will try. But I can answer these for now.


nothings impossible... but since now replacment MB under hand. please do the following
Remove Load...
1- disconnect all 4 ribbon between T-CON & LCD from T-CON side and never connect them again until you finish trouble shooting

DONE


2- same to WIFI /BT Module disconnect them


DONE


3-put yours DMM Probe always on T-CON Fuse F1 to remark the 12V

DONE



4- Insert USB pen with any kind of media content at any USB Port. prefer with LED Indicator to know if it blinking during start ( we need to know the DC-DC Circuit on MB produce USB 5V.

NO 5V ever in any state any board. Tested both with USB stick and DMM.


4- Plug the tv in wall socket. at time TV start (Toslink light goes on ) plug the TV from wall socket.. and never use the RC AGAIN::: to make us sure the MB registered the Last state mode ( mean always when you plug it at wall will start.. an not goes to STB )


Board 1
Plug in = solid red = standby = no Toslink. Button or RC out of standby = Toslink on. Toslink always off in standby on out of standby.


Board 2 (arrived yesterday, different board version.)
Toslink seems random and mostly off. Can't figure out any pattern/reproduce. Update - it does seem like it goes on one time the firsy exit standby but then can't go on again until unplug for several minutes.



All boards last state never registered; always standby when unplugged 10 seconds plugged back in.


5- please record movie on yours MB during this test and upload it here.. and tell the result about T-CON 12V.

All boards = TCON near 12V always in out of standby, 0v standby.




Thanks!

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

So my thought is since it seems unlikely that original board failed and then 3 more were DOA it seems possible that the boards were good but something killed them right away.

Since PSU measurements seem all OK and we have lit backlight OK and also all pixels (half a screen at a time) it seems like TCON, TCON to panel pcb and panel are OK. PSU to MOBO cable seems OK too so this leaves only switch ribbon cable and the 2 X motherboard to TCON. So I will check for shorts there... if there are then this could fry every board maybe? Nope checked w/microscope at least all wires seem ok.

[Diah]

Re: LG 70UH6350 (UB.BUSMLJr)

there are SOS signal come some where to MB.. i would suggest back to point where you did the test with external 3.5V to run the PWB as stand alone.. with out MB.. and measure all yours BL socket pins ... any group it should have same current Value.. if there are different mean this group had shorted LED. you need to be sure of this.. because when they lit on with just the way you did.. doesn't mean they are okay.... and also when you force them to on... the protect circuit which send SOS to MB will be disabled or over loaded too because MB disconnected at the test.

[Storyteller12]

Re: LG 70UH6350 (UB.BUSMLJr)

If I recall correctly my mainboard that was bad had a bunch of shorted caps. Not positive. It I think it was he main processor that went bad.

Test caps on mainboard for shorts

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

there are SOS signal come some where to MB.. i would suggest back to point where you did the test with external 3.5V to run the PWB as stand alone.. with out MB.. and measure all yours BL socket pins ... any group it should have same current Value.. if there are different mean this group had shorted LED. you need to be sure of this.. because when they lit on with just the way you did.. doesn't mean they are okay.... and also when you force them to on... the protect circuit which send SOS to MB will be disabled or over loaded too because MB disconnected at the test.

OK thanks. For doing this without removing back from panel do I need to buy LED tester or I can do just with DMM?

[Diah]

Re: LG 70UH6350 (UB.BUSMLJr)

only with DMM... read the print chart of each socket ( printed on PWB) to know the Anoden and it related Pins.

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

OK cool thanks. Would you mind explaining what and how to exactly test sorry?

I think you will have me test with the BL ribbon connectors connected but use the pins of the connectors to test (I have some hook leads.) But not sure what I'm testing just the LED+ pins while tricked on?

[Diah]

Re: LG 70UH6350 (UB.BUSMLJr)

okay... first look at the PWB socket from down side.. see for example socket P801 if the LED+ 1 & 2 are connected together at circuit. or separated

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

Is this thread here?

https://www.badcaps.net/forum/showthread.php?p=1131857

Also on a youtube video but the person did not bother to warn against cutting the safety wire as a permanent solution.

These particular boards through do not have that line on the power connector though it seems.

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

So I am not sure how pins are numbered. I see from a overhead view oriented as picture that pin 1 on each is the upper right. But is pin 2 on the row under or would it be adjacent left?

[Diah]

Re: LG 70UH6350 (UB.BUSMLJr)

Here pic. I will figure out the answer.

they look all 3 sockets led+ are connected together
if this case then take one as anode probe and measure all other vc .. write down the result

[nonsub]

Re: LG 70UH6350 (UB.BUSMLJr)

So I am not sure how pins are numbered. I see from a overhead view oriented as picture that pin 1 on each is the upper right. But is pin 2 on the row under or would it be adjacent left?

So if I am reading right then P803 anodes are joined pin 7+8 right?