LG 65EC970v Black Screen and no Audio

[axlerose]

Hi Folks

I am hoping someone can help as i am at a loss, tv went black screen power stays on, i have tested the power board and all voltages are good except the 24vd for the panel. I have read on here that the MB will stop power to panel and T-con if there is issues, i have taken all boards out and discovered that the t con has 60 caps shorting to ground, 30 on the front and 30 on the back of the board. I did start to remove a couple and they tasted fine so didnt remove any more as this must be something else that is the cause,these are the caps that read short. Front of board: C749 C751 C748 C693 C694 C697 C837 C838 C839 C840 C1134 C1133 C1134 C1135 C1143 C1142 C1144 C1145 C741 C854 C855 C856 C857 C1138 C1139 C1140 C1141 C1152 C1154 C1151

Back of Board:
C1147 C1146 C1148 C1149 C1160 C1150 C1161 C1162 C987 C427 C695 C696 C747 C752 C753 C750 C754 C742 C701 C700 C1009 C1153 C1164 C1165 C1159 C1163 C1158 C1157 C1155 C1180. I think this is all of them, i have included some pics but its pretty hard to photograph as it is a big board. I hope some of you guys can help as i hate waste and would love to be able to bring life back to the tv.
Many thanks
Chris

[nomoresonys]

Re: LG 65EC970v Black Screen and no Audio

how are you testing them?

[ikmpch]

Re: LG 65EC970v Black Screen and no Audio

So many caps can not be short at one time. Most likely you have one short component giving you this false error.

You can try the following method:
Remove/isolate the T-con board. The T-con usually gets 12 volts power supply so attach 12 volts DC external source + lead to power input point (near connector for main board) and the neutral to any ground point on the T-Con board. After the connection check which item is hot (you can spray iso propyl alcohol solution on the T-Con board). The evaporation will tell you which component is getting hot.
You can also search on You-Tube for short component check. Hope it helps.

[diif]

Re: LG 65EC970v Black Screen and no Audio

No, it's not advisable to inject working voltage.
You only need to inject 1.2/1.5v and the risk of damage to ics is reduced.
Measure the resiaatance to ground on all the coils.

[lotas]

Re: LG 65EC970v Black Screen and no Audio

Here the output is only 1.2v on these rails (powering the processor core), so there should be very low resistance.
Where did the Mosfet Q8 go?

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

how are you testing them?

Hi, Continuity mode

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

So many caps can not be short at one time. Most likely you have one short component giving you this false error.

You can try the following method:
Remove/isolate the T-con board. The T-con usually gets 12 volts power supply so attach 12 volts DC external source + lead to power input point (near connector for main board) and the neutral to any ground point on the T-Con board. After the connection check which item is hot (you can spray iso propyl alcohol solution on the T-Con board). The evaporation will tell you which component is getting hot.
You can also search on You-Tube for short component check. Hope it helps.

Hi, thank you

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

No, it's not advisable to inject working voltage.
You only need to inject 1.2/1.5v and the risk of damage to ics is reduced.
Measure the resiaatance to ground on all the coils.

Hi, thanks will try if i can find a power source as still waiting fo dc bench supply

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

Here the output is only 1.2v on these rails (powering the processor core), so there should be very low resistance.
Where did the Mosfet Q8 go?

Hi, thanks for your reply, i removed the mosfet to make sure it was not grounded as most of the caps are around the R47 coils on both sides of board, i will replace mosfet, any idea as to so many caps reading short, thanks

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

No, it's not advisable to inject working voltage.
You only need to inject 1.2/1.5v and the risk of damage to ics is reduced.
Measure the resiaatance to ground on all the coils.

Hi, which coils do you mean R47? and please can you tell me how. thanks

[Diah]

Re: LG 65EC970v Black Screen and no Audio

this is wrong way to test and determine fault on OLED TV.. we do have covered over here many post of this model.. just read and follow you will know where are the fault

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

this is wrong way to test and determine fault on OLED TV.. we do have covered over here many post of this model.. just read and follow you will know where are the fault

Hi, i have read loads on here and still can not work out whats wrong with it, would need more help to find problem. Thanks

[Diah]

Re: LG 65EC970v Black Screen and no Audio

it sound you never read any...lol .. you wrote there are no 24V from PWB to T-CON.. but you didnt wrote if the tv response to Remote on / off... so the below points related if there are response via RC.
then.
1- did the optical port on MB lit red on ? if yes read 2.
2- insert USB pen on its mpg4 ( video format ) on the root of the stick.. and insert too usb / air mouse at any other port and turn on.. while its turn on remove the mouse / click left right.. this will help in case the TV in sleep mode
3- if above didnt help. while its on send command "IN_STOP " with service RC or any other DIY or android apk ( mobile with IR sender such galaxy s5) followed with 0413 tv should go to stand by... plug it out from socket for few minutes then plug it on you should hear first install music or bild come back.

if this didnt help... go back where you told us read it... and find out how to run the panel as stand alone.

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

Hi Diah
I did read posts and a lot more, panel is dead, nothing at all. I havedone stand alone test with power on and drv on 3.5v, when turn on power psu clicks and multi meter reading to jumpers for power on and drv on are constant 3.5v and there is also the 24v going to tcon board but not a flicker on screen, i think this is because there is a major short some where on tcon as specified and this is stopping panel from showing anything, have you got any other ideas? i could replace tcon but they are expensive for this tv and don't want to put good one on if panel has short and it wlll kill new tcon, need to find way to find short on tcon

[Diah]

Re: LG 65EC970v Black Screen and no Audio

Hi Diah
I did read posts and a lot more, panel is dead, nothing at all. I havedone stand alone test with power on and drv on 3.5v, when turn on power psu clicks and multi meter reading to jumpers for power on and drv on are constant 3.5v and there is also the 24v going to tcon board but not a flicker on screen, i think this is because there is a major short some where on tcon as specified and this is stopping panel from showing anything, have you got any other ideas? i could replace tcon but they are expensive for this tv and don't want to put good one on if panel has short and it wlll kill new tcon, need to find way to find short on tcon

there are some things wrong with yours stand alone test...
in general OLED Panel / Power boards stand alone test should be considered on this 3 basis.
1- T-CON 24V feed come always via power boards.

2- if the T_CON driver boards 12V feed come via LVDS from Main boards then..
A- the LVDS between Main boards and T-CON should disconnected
B- the socket from Power boards to main boards should disconnected
C- after bridge STB to Power_On and Dr_on. we take 12V from PWB socket and fed it to T-CON driver boards to F1 ( always this fuse will be close to LVDS socket )

3- if the t-con 12V feed come direct from PWB
A- LVDS between MB and T-CON should disconnected
B- the sockets between PWB and MB should disconnected
C- we bridge only on PWB socket STBY to Power On & DRV_ON.

so see where are the wrong you were on.

[axlerose]

Re: LG 65EC970v Black Screen and no Audio

Hi Diah

The test i have done is no 3 on your list as the pwb supplies the 12v and 24v to tcon board, mb was totally disconnected, still nothing on screen. Any other ideas? thanks

[Diah]

Re: LG 65EC970v Black Screen and no Audio

on the same test 3 use one flame car bulb 24V or 2 flame of 12V connected on the 24 line. check if the line cut off. this test described at PDF we upload before of this Model threat.

[Davi.p]

Re: LG 65EC970v Black Screen and no Audio

Hi, bad pictures.. can you make one of the whole board no flash at the sun light? keep steady