55EC930V Power On - Power Off failure

[nixmoon]

Hi Guys,

I know there are some other threads, but it seems the faults are little different, that is why I opened another thread, hope that was ok!

I have a little problem with my LG 55EC930V TV Set. I bought it on ebay for 80 Euro. The relay inside the TV will klick, logo on the bottom will be lid and after ~3 seconds I hear another klick and logo fades out.
I checked the PSU and when using both jumpers, 3,5V to DRV-On and PWR-ON, all voltages are ok and in range.

Then I tried to set the PWR-ON jumper (DRV-ON was set all time) while all boards and cables were connected and I got the automatic test pattern from the TV, switching from white to black, red, blue and green. I took a video and here are some pictures from it. So I thought, the panel is fine and used the power only mode and again, I got a white screen with the power only box showing but shortly after I left the power only mode, the TV somehow crashed, right side went dark and shortly after that the whole screen was showing horizontal lines black and white line. (pictures attached)
From time to time I am able to reproduce this, but most of the time it will hang within the first second when showing the test sequence, mainly green or blue with black stripes. Power only mode also doesn't work anymore.

Yesterday I received 2 other used T-Con boards but same result. Without the DRV-ON jumper nothing happens, with the jumper the same fault as mentioned before, as you can see on the attached failure picture.

Any ideas? Is my panel broken even though it seems to be fine from time to time?

Is it the Mainbaord? Should I try to get a replacement?

I was thinking to remove R11408 (0 Ohm) of the Burnt detection signal on the mainboard to see how the TV will behave?! Any thoughts about that?

BTW All fuses and cables are checked several times and no burnt smell nor component were seen on any of the boards.

I have Mainbaord Version 1.1 (without LED and micro switches).

Any help is appreciated!

[Diah]

Re: 55EC930V Power On - Power Off failure

yours first testing to force PWB turn on and the Main Boards connected was absolute wrong. and you do it many time thought... its much like you toasted the MB.

[nomoresonys]

Re: 55EC930V Power On - Power Off failure

Yep, ALWAYS unhook the cable from powerboard to mainboard when doing that test, hopefully you didn't mess anything up, try a firmware update thru usb, some tvs will update automatically, yours might not.

[nixmoon]

Re: 55EC930V Power On - Power Off failure

Thanks for the advice, after trying everything mentioned here in the forum that was my last idea and I thought I made some progess finaly seeing the panel working. Maybe I was wrong.

Back to the problem, when I check the start up sequence I see the MB just giving the DRV-ON signal to turn on the 24V rail for the T-Con and direct after that it will power down. That was the case since the beginning. Maybe I need to check the feedback signal from the T-Con, will do that next.

Anyhow my main concern and question is, is the Panel still ok? Has anyone had that kind of issue seen before? Is it the MB or the Panel?

If it's the MB, I will try to get a replacement MB.

[nomoresonys]

Re: 55EC930V Power On - Power Off failure

Pretty sure its not the panel, bad panels don't present like that, seems like a firmware issue.

[nomoresonys]

Re: 55EC930V Power On - Power Off failure

Zomi just had a similar problem with the colored screens, see his thread, it was a bad cable.

[nixmoon]

Re: 55EC930V Power On - Power Off failure

I checked his thread, but I think it is not the same. I get the test sequence when forcing both DRV ON and PWR ON signals while MB is connected. When this works I can normally switch to Powe Only mode with service RC signal, but still needs the DRV ON jumper.
I check again with a scope the start up sequence I found in another thread and the IC3000 holds the pin19 down all time so in this condition the 24V for T-Con will not be set in normal condition, BURNT_DET is also low, not causing the IC3000 to withhold the 24 V.

Only with the jumpers set the BURNT_DET signal is low at the beginning, it goes up when the screen freezes or it freezes because it goes up, I don't know...
Unfortunately I can't find any other documentation about the reasons why the IC3000 won't turn on the 24V for T-Con.

The only documentation I found is from drops206 at this thread: https://www.badcaps.net/forum/showthread.php?t=69446

Just noticed there is a Power on/off sequence mentioned, will check now how far it goes.

[nomoresonys]

Re: 55EC930V Power On - Power Off failure

Try turning the tv off with the off button on the tv, NOT remote then turn it on with the remote, works for some.

[Diah]

Re: 55EC930V Power On - Power Off failure

IC3000 holds the pin19 down all time so in this condition the 24V for T-Con will not be set in normal condition, BURNT_DET is also low, not causing the IC3000 to withhold the 24 V.

with out any jumper all boards connected to PWB. disconnect the LVDS cable from MB side to T-CON driver boards.. put USB stick at any USB port. feed signal from HDMI external device.. then turn on..
notice... do you got Sound? did the LED indicator of the USB lid on.. or blinking.. you can also check the red led indicator of optic sound output plug

[nixmoon]

Re: 55EC930V Power On - Power Off failure

Problem is that the TV turns off after around 3 seconds by itself, even without LVDS cable connected. LED of the USB stick does not lit up during that period of time and no sound.

[Diah]

Re: 55EC930V Power On - Power Off failure

Problem is that the TV turns off after around 3 seconds by itself, even without LVDS cable connected. LED of the USB stick does not lit up during that period of time and no sound.

it sounds to me its go to standby after the 3 seconds you are talking on.( Last State)

also after its turn off turn it on with RC give time and look on points i asked before...

if its turn on ..and later you plug it out from wall socket.. it will turn on next time and remain on. this called ( power on last state )

[nixmoon]

Re: 55EC930V Power On - Power Off failure

Just to make it clear for me, next test I should try is:
- Disconnect LVDS cable (without power supply connected to the Set)
- Connect power supply, wall plug
- Push power button on Remote and within the 3 seconds unplug from wall
- Replug to wall and Set should stay on, so I can check sound from input, USB stick LED and SPDIF light.

I will do that as soon I am back home!

Thanks so far for the support!

BTW I checked the M14 Power SEQUENCE mentioned in the Schematics and all the signals go to high state before the TV goes to STB mode by itself.

[Diah]

Re: 55EC930V Power On - Power Off failure

Just to make it clear for me, next test I should try is:
- Disconnect LVDS cable (without power supply connected to the Set)
- Connect power supply, wall plug

again wrong. who write so ??

every things connected to Power boards... only LVDS between main boards and T-Con driver boards disconnected from Main boards side.

plug in wall.... it will go on then to off after 3 seconds ( as you wrote before).. then with RC turn it on... if its turn on.. send with service RC via any android mobile with IR sender ( IN_STOP ) command.. to roll back all driver.. report your result.

[nixmoon]

Re: 55EC930V Power On - Power Off failure

Disconnect LVDS cable (without power supply connected to the Set)

Sorry for the misunderstanding, I ment to say, without 230V power supply connected to the TV Set.

When I try to turn it on with RC it will always power off after a few seconds and in that time no USB flashes or IN_STOP command worked, tried it already several times before.

Is there any way to boot the MB without LVDS connected to have for example enough time to check all voltages on the ICs on the MB?

[Diah]

Re: 55EC930V Power On - Power Off failure

Sorry for the misunderstanding, I ment to say, without 230V power supply connected to the TV Set.

When I try to turn it on with RC it will always power off after a few seconds and in that time no USB flashes or IN_STOP command worked, tried it already several times before.

Is there any way to boot the MB without LVDS connected to have for example enough time to check all voltages on the ICs on the MB?

let hope you didn't toasted the MB.. so need only reasonable test to do.
you may start with 24V line on MB. you have on the socket which connected between PWB & MB 3 line of 24V which feed two Audio amplifiers on MB.
these line need to terminated at MB side. to be sure we don't have issue at this point t kill the 24 V. terminated then turn on

[Diah]

Re: 55EC930V Power On - Power Off failure

second Test:

every things in place.. LVDS connected
only the socket between PWB to T-CON driver board (24V) DISCONNECTED . then turn on and check.

[nixmoon]

Re: 55EC930V Power On - Power Off failure

these line need to terminated at MB side. to be sure we don't have issue at this point t kill the 24 V. terminated then turn on

How do I kill the 24 V?

I checked all voltages (1.1V; 1.5V; 2.5V; 3.3V; 3.5V; 5V; 12V; 24V) and regulators on the MB, everything is stable for the 3 seconds the relay is on.

Regarding the seconds test you mentioned, it will have no effect, because the MB never gives the DRV-ON signal so 24V is never applied to T-CON.

[nixmoon]

Re: 55EC930V Power On - Power Off failure

I think the panel is broken, always shortly after the DRV-ON signal is set, the T-CON will set BURNT_DET/T_CON_SYS_POWER_OFF/LED_R which will give IC3000 the command to shut down the whole TV Set. Please correct me, if I am wrong!

I will have a last try with another MB from ebay next week, but my hopes are low.

Although it happened a few times now that the T-Con didn't set the signal but only when I turned the TV on via POWER_ONLY mode, but I had now picture on the screen, it stayed black. No sound from external source, USB would initialize, SPDIF lights up but no command from RC will work. No IP received from DHCP server. TV will be seen detected by graphics board from my laptop, but as I said, no sound or picture on the TV. When I then unplug from wall and replug, TV will set on by itself but power off after 3 seconds when BRUNT_DET signal from T-CON is received.

[nomoresonys]

Re: 55EC930V Power On - Power Off failure

Could be wrong but I think a good mainboard will solve the issue.

[Diah]

Re: 55EC930V Power On - Power Off failure

How do I kill the 24 V?

I checked all voltages (1.1V; 1.5V; 2.5V; 3.3V; 3.5V; 5V; 12V; 24V) and regulators on the MB, everything is stable for the 3 seconds the relay is on.

Regarding the seconds test you mentioned, it will have no effect, because the MB never gives the DRV-ON signal so 24V is never applied to T-CON.

well let me explain.
the 24V on the set used for Panel power and audio amplifier only, T-CON used 12V only from Main boards via LVDS.

so if we terminated the 24V audio amplifier circuits feeding which usually will be via L or low R before the circuits let us know the 24 error causes.

same way when we disconnected the 24V sockets between PWB and T-CON driver.

I checked all voltages (1.1V; 1.5V; 2.5V; 3.3V; 3.5V; 5V; 12V; 24V) and regulators on the MB, everything is stable for the 3 seconds the relay is on.

from yours OP photos and the voltage reading... the main IC are suspected so much as BGA. it will worth to take out the cooling plate of it and put plaster on it and components near by and the downside of the boards too... and heat it with hot air gun. hope it will work.