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....
pedrolane
Member
Last Activity: 10-31-2023, 04:12 AM
Joined: 03-30-2023
Location: Lille
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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....Leave a comment:
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Re: LG 55EA970V OLED / black screen
Wifi bluetooth module is disconnected
As well as camera moduleLeave a comment:
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Re: LG 55EA970V OLED / black screen
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.
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...Leave a comment:
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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.Leave a comment:
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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 ?Leave a comment:
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Re: LG 55EA970V OLED / black screen
I have several usb ttl adapters. I've used one based on Prolific PL2303HX chip, which is designed for 3.3v arduino. [URL="https://www.adafruit.com/product/954"]Product page here[/URL]
So I plugged RX TX and GND to header P101.
While I can see receive garbage, i can't find anything useful. I have 1 byte of data each time I send a carriage return, thats all.
I tried at 115200 8N1 and various other settings on speed, data bits, parity and flow control without luck. Not sure this debug mode is enabled...Leave a comment:
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Re: LG 55EA970V OLED / black screen
Again, thanks for your time
Yes, that seems quite impossible
That's the one in TV set right now, but it is unplugged as asked (both LVDS and 24v)
No DRVON on MB, so no DRVON on PSU. So no 20v nor 24v from PSU. So no voltages on tcon. I never never never saw any MB put DRVON up.
The only way to power the tcon is to force DRVON on PSU AND brings 12v on LVDS fuse at the same time.
With LAN plugged in the interface comes up (5v) but no negotiation, no...Leave a comment:
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Re: LG 55EA970V OLED / black screen
We already tried that. I tried it again without result.
The switch sw100 pull high on IC100 GPIO20 (debug pin)
The switch sw300 reset micom (i can hear the relay open / close)
Powered on with P.Only (or with ON button) I still dont have 12v on LVDS pins.
I do have 12v on 2 pins of Q2302 as measured a few days ago.
Now I'm wondering what the purpose of little headers P3000 P3001 P101 is. All of three have 4 pins and I can see in schematics that for P101 at least,...Leave a comment:
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Re: LG 55EA970V OLED / black screen
So I've unplugged ribbons on tcon side, I only have 3 : 2 LVDS from MB + 1 20v power from PS
I've check with 3 MB, same results :
- I can power on with P.ONLY
- I have 3.5v on PWRON, 12v and 24v from P202
- but nothing on SPDIF output
- I have 5v on USB, IR service RC is okay, front logo is lighting on then off
- if I do nothing the set remains powered up
- if I p.only, then exit, then turn off (by unplugging from wall), nothing new when turn on, still nothing on spdif
the MB seems...Leave a comment:
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Re: LG 55EA970V OLED / black screen
Yes, we thought MB was in "locked" mode. But we never managed to get out of this mode with P.Only on SVC remote, nor reset code etc. We also tried to reset MICOM with switch0 on MB. No luck.
I've already changed the TCON, without results. The second TCON is fine with self test too.
Is it possible the MB provide 12v to TCON for just some milliseconds, the diagnose an issue and shut the 12v ?
If you have any idea of test I can do, let me know....Leave a comment:
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Re: LG 55EA970V OLED / black screen
@Diah : With digital multimeter in capacitor mode, I measure 0.190 uF for C2347 on all 3 MB I have.
(MB totally unplugged, no power). Obviously I didnt unsolder the Capacitor from board.
I ve also test in ohm mode, value goes from 0 to ~4Mohms, so the capacitor seems to charge then block current, as (I think) it is supposed to.
I dont know what other test I can do on this C2347.
@dvadssc
Sorry, I dont have a golden source for these manual. I guess you should find with Google....Leave a comment:
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Re: LG 55EA970V OLED / black screen
ok guys. so here are a closed picture of the panel vcc circuit (this is a spare card have, R7216 is still there).
Please also find attached my measurements. I guess all is correct, but PANEL_CTL is near 0v. PANEL_CTL is PIN4 of MICOM.
I also put the schematics, in case you dont have it.
I dont know whether panel_ctl should be up after / before inv_ctl. But anyway, both are near 0v....Leave a comment:
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Re: LG 55EA970V OLED / black screen
I removed R7216 (100 ohms) and now LED_R is left opened, no more connected to LVDS pin 44.
Unfortunately it doesn t change anything. I can power on with P_ONLY but still no DRVON nor 12v on LVDS, and nothing on screenLeave a comment:
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Re: LG 55EA970V OLED / black screen
The root issue is that there is no DRVON while power on, so no 24v on TCON.
But I neither had 12v on LVDS 48-51 pins.
However I can measure 12v near that pins on Q2301 and Q2302 (tell me if you need schematics).
I didn't analyse too much but it seems the panel_ctl (micom pin4) is down, so these mosfet are opened circuit.
It might seem logical with hypothesis the T_CON_SYS_POWER_OFF force the MICOM to keep panel shut.Leave a comment:
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Re: LG 55EA970V OLED / black screen
I do confirm with diode test that LVDS PIN44 is connected to R7216 then to MICOM pin 16. It is qite easy to follow path on board.
But I can't understand something. If everything is plugged in place, I do not have 12v on LVDS pins 48 to 51. So the TCON is shut off. How could it send back a "panel burnt" signal on PIN 44 ?
Again thanks for your help. It's amazing how this looks fluent to you only with descriptions and pictures !
I will try to cut off the copper path of this pin on one of the MB I have, and...Leave a comment:
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Re: LG 55EA970V OLED / black screen
Micom pin 16 is labelled LED_R which is connected to T_CON_SYS_POWER_OFF (pin 44 of LVDS). I put the schematics on post 31, there are some R and capa around.
Do you think I may "break" the copper path to disconnect this pin ? I can remove R7216 as well. I've never measured 3.5v on this pin, so not sure if this is a good way to go.
I put the "training guide" here. There are some useful infos....Leave a comment:
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Re: LG 55EA970V OLED / black screen
So I've made measurements with TCON and PS only (MB totally disconnected).
PWRON and DRVON are forced on. And 12v brought directly from PS to TCON "right" fuse.
Color cycle pattern is working.
It is not easy to check with these small pins. But as far as I can tell the pin 44 "t_con_sys_power_off" on CN4 is 0v.
I do have 3.5 on pins 2, 3, 7. And 12v on 48 to 51 (back from tcon). I also have 3.5 on various pins between 11 and 40.
I've found some basic TCON schematics, I attached he...Leave a comment:
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Re: LG 55EA970V OLED / black screen
okay here is the diagram
on my mb this is pin 44, not 40.
On R7216 I have 0v when pwr off, and 0.3v when pwr on. Don't seem to be sufficient to be considered "high".
if I switch the TV on with p-only, it is supposed to bypass the "burn detection", however there is still nothing on screen....Leave a comment:
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Re: LG 55EA970V OLED / black screen
okay Diah, that seems a good hint !
I've found that in a troubleshoot manual :
[CODE]NOTE3 (Panel Burn Detection): The Panel is also monitored by the Main board for “Burn Detection”. This indicates an internal short on its grid
lines. There is a line on the Vx1 cable P7100 pin 40 called “T_CON_SYS_POWER_OFF”.
This line is routed through R7101 and renamed to “LED_R” sent to the Micro pin 16. This line is normally 0V when the Panel is operating
normally. If the Panel's internal grids short, this line...Leave a comment:
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