LG 55EA970V OLED / black screen

[pedrolane]

Re: LG 55EA970V OLED / black screen

I unplugged DRV_ON from PSU side, then force it UP with PWRON
No change, I still dont have 12v on MB

And since DRVON is 0 on PSU side, 20v will never start on PSU, so TCON remains off

Do I have to force DRVON on BOTH sides ? So I will have 20v on PSU AND PANELCTL up ?

[Diah]

Re: LG 55EA970V OLED / black screen

I unplugged DRV_ON from PSU side, then force it UP with PWRON
No change, I still dont have 12v on MB

And since DRVON is 0 on PSU side, 20v will never start on PSU, so TCON remains off

Do I have to force DRVON on BOTH sides ? So I will have 20v on PSU AND PANELCTL up ?

how it come you dont have 12V on MB.... ???
12V will be generated and send to MB when power on signal send from MB to PSU.. you did some things wrong..

[Davi.p]

Re: LG 55EA970V OLED / black screen

if you see only garbage there is a possibility that there is a level shifter on board, check if there is a chip called something-232 or whatever that is connected to the serial port, check its datasheet, possibly it is a regular rs232

[pedrolane]

Re: LG 55EA970V OLED / black screen

Sorry I wrote too fast.
I meant no 12v on lvds socket on mb side.
I do have 12v on various places on mb when pwr on.

[Diah]

Re: LG 55EA970V OLED / black screen

Sorry I wrote too fast.
I meant no 12v on lvds socket on mb side.
I do have 12v on various places on mb when pwr on.

so you may have the socket between PSU and MB at MB side had burn maybe...
you need to check of continuously between the pins direct on the 2 boards from downside

if every things fine... then keep the tV on at the last try ( drv_on ) wire unplugged and jumper to power on

[pedrolane]

Re: LG 55EA970V OLED / black screen

if you see only garbage there is a possibility that there is a level shifter on board, check if there is a chip called something-232 or whatever that is connected to the serial port, check its datasheet, possibly it is a regular rs232

The PIN is just labelled GPIO23 / UART2 directly from LG chip "IC100
LG1154D_H13D", then this little circuit (see attached). So I guess it is 3.3v TTL and my usb-serial should be fine. Maybe the chip enters debug state only with the debug pin to UP. Dunno.

so you may have the socket between PSU and MB at MB side had burn maybe...
you need to check of continuously between the pins direct on the 2 boards from downside

if every things fine... then keep the tV on at the last try ( drv_on ) wire unplugged and jumper to power on

I've made some tests with PWRON connected to DRVON on PSU side, connected to DRVON on MB side, and connected to both (see picture). But nothing, still no 12v output on LVDS on MB side. However I still can measure 12v on some transistors (as earlier tests).

I've checked the ribbon that goes from PSU to MB, it is fine. And regarding socket on PSU / MB I've also tested as far as I can (some pins are difficult to spot), and that seems fine. and remember I've checked with 2 different PSU, 3 MB and 2 TCON :-)

[Diah]

Re: LG 55EA970V OLED / black screen

did you remember i asked you to do all test after we move load from MB... disconnecting wifi module & Bluetooth module at IR section... & speakers out

[pedrolane]

Re: LG 55EA970V OLED / black screen

Wifi bluetooth module is disconnected
As well as camera module

[Diah]

Re: LG 55EA970V OLED / black screen

Wifi bluetooth module is disconnected
As well as camera module

then you need to follow the bulb test when you running panel as stand alone to see if the panel 20-24V current.

its same way if you run the panel for long time of time 1 hour for example. if there issue at panel will be shown on the front panel.

[pedrolane]

Re: LG 55EA970V OLED / black screen

then you need to follow the bulb test when you running panel as stand alone to see if the panel 20-24V current.

its same way if you run the panel for long time of time 1 hour for example. if there issue at panel will be shown on the front panel.

Is this test really needed ?
I've check with 2 different PSU, and the colour cycle test is fine.

[Diah]

Re: LG 55EA970V OLED / black screen

Is this test really needed ?
I've check with 2 different PSU, and the colour cycle test is fine.

bulb test considered for Panel issue not PSU. to check if the panel used more current as it designed.

[pat0500]

Re: LG 55EA970V OLED / black screen

Hello All,

i have a 55UB850V which also has no DRVON and also missing 12V at TCON did you already find a solution for this matter?

kind regards,
Patrick Postma

[pedrolane]

Re: LG 55EA970V OLED / black screen

Hello All,
i have a 55UB850V which also has no DRVON and also missing 12V at TCON did you already find a solution for this matter?

Unfortunately no, I don't.
Despite the help of several gurus here, my TV set is still stuck.
I don't have much time these days but plan to make some tests as advised in earlier posts.

[sergio27992]

Re: LG 55EA970V OLED / black screen



Unfortunately no, I don't.
Despite the help of several gurus here, my TV set is still stuck.
I don't have much time these days but plan to make some tests as advised in earlier posts.

Reflow the CPU and it should work.

[nomoresonys]

Re: LG 55EA970V OLED / black screen



Surely these are the simple ones to fix and the money makers though?

Nope, backlights are always a full teardown pain in the ass, can be pretty impossible to get the frame back together and stable in some models, and really no way to properly fix a bad panel unless it's a bad component that you can find on the driver boards or a whole new panel which is way too costly.

[MigRic]

• Hi Pedrolane
  
  Did you found the problem on your LG 55EA970V?
  
  I have one here with exactly the same symptoms! Power-on OK with 24V and 12V present on P202 . No DRV-ON signal *, so no 20V to the T-CON, also no 12V to the T-Con from the LVDS (12V rail present on MB)
  
  * 20V are present if DRV-ON is pulled high (3.3V) externally. So the power supply is OK including PFC
  
  Thank you and best regards

[pedrolane]

No, the TV set is still black :-(

There seems to be a shortage on panel. Some people advice to check ground shortage on all the coils at the bottom of the panel, then remove any defective one. But I can't figure out how to really check with such a short.
Sorry can't help more

[Davi.p]

Hi, there is no short on the tcon board, otherwise no test screen would be shown...
Can you post a model or a data table / sheet or naming of your usb-serial cable? Is it for Arduino expressely or it does work with general rs232 devices?
We cannot rule out the main board on the basis that are 3.. common problems are standby processor and the main processor.. if you have an hot air station a slight heating for testing purpose to both is a thing to do...