Problem LG 49UB850V (Mainboard: EAX65684604 / EBT62954607)

[Malva]

Hi everyone,
I'm trying to repair my LG 49UB850V TV (WebOS 1.0, UHD model from 2014).
Mainboard model: EAX65684604
PCB marking: EBT62954607
SPI chip: Winbond W25X20CLNIG Problem description:


Originally, the TV would turn on (backlight and LED OK if I force them on), but it shut down as soon as any input was received from the IR sensor or remote. The backlight and power board were working fine.

After testing and verifying the voltages (DRY ON, PWR ON, 12V/24V rails), I suspected a corrupted SPI firmware. What I tried so far:

• I bought another mainboard (same model: EAX65684604) from AliExpress.
  • That board works, but has no Smart functionality, no antenna/tuner support, and only one HDMI input working.
  • It seems to be a minimal or hotel firmware version.
• I dumped the firmware from that board and flashed it into my original one using a CH341A programmer and SOIC8 clip.
• After the flash the TV reports the same problems.
• I have a backup of the original firmware.

I'm looking for a clean, working dump (.bin) for this mainboard and TV model or for some advices.
Feel free to share it directly or link it here. Thanks a lot in advance!

[Davi.p]

have you compared the original dump with the one from chinese mb with HxD?

[lotas]

The settings are stored in eeprom (AT24C256C), not in spi flash (W25X20).

[Malva]

have you compared the original dump with the one from chinese mb with HxD?

Yes, they have some differences but I tried anyway.
For istance:

• At byte 24: 0xBA (AliExpress) vs 0xB9 (LG original);
• At byte 20482: 0xEC vs 0xD6;
• At byte 20485: 0xA3 vs 0xAA;
• At byte 20490: 0x85 vs 0x94;
• and many others.

As I didn't figure to find a stock SPI firmware I tried this way.

[Malva]

The settings are stored in eeprom (AT24C256C), not in spi flash (W25X20).

Should I try to erase it and force the tv to regenerate it?
Thank you

[lotas]

This worked in old models, in new smart models the region, Syrian numbers, mac address are registered.... Try doing IN STOP through the service remote (before any manipulations make a backup of the original chips).

[lotas]

To disable the LG Hotel Mode on your TV, you need to enter the service menu using the code 1105, and then disable the "Hotel Mode" function.
Here are the detailed instructions:
1. Enter the service menu:
Press and hold the "Home" button on the remote control for more than 5 seconds.
Enter the code 1105 using the number buttons on the remote.
The "LG HOTEL MODE SETUP" menu should open.
2. Disable Hotel Mode:
In the "LG HOTEL MODE SETUP" menu, find the item responsible for hotel mode (usually it is the first item in the list).
Use the up/down buttons on the remote to select this item.
Press the "OK" or "Enter" button on the remote.
Change the value to "Off" or "Disabled".
3. Exit the service menu:
Press the "Back" button on the remote control.
The TV should return to normal operation.
The hotel mode is now disabled and you can use the TV as normal.
Additional information:
If you are having trouble with code 1105, try other common codes such as 0000 or 0413.

[Davi.p]

when programming the flash, did you do the verify procedure?

[Diah]

To disable the LG Hotel Mode on your TV, you need to enter the service menu using the code 1105, and then disable the "Hotel Mode" function.
Here are the detailed instructions:
1. Enter the service menu:
Press and hold the "Home" button on the remote control for more than 5 seconds.

if this so easy to disable Hotel mode, then all Hotel user will have access to change what they like,, only using Service Remote and send IN_Stop command followed with 0413 TV go to STB,

[lotas]

if this so easy to disable Hotel mode, then all Hotel user will have access to change what they like,, only using Service Remote and send IN_Stop command followed with 0413 TV go to STB,

1105 - access code to LG Hotel Mode. You can change the code in the LG Hotel Mode menu. Accordingly, after changing the password, to enter LG Hotel Mode, you no longer need to enter 1105, but the same password that the hotel administrator set.

[Diah]

well lotas still IN_STOP the powerful command to put the set back to shipping state even if the administrator changed H.Mode PSW

[lotas]

I already wrote about this (IN STOP) in post 6.

[Malva]

This worked in old models, in new smart models the region, Syrian numbers, mac address are registered.... Try doing IN STOP through the service remote (before any manipulations make a backup of the original chips).

I am unable to find the EEPROM Chip on my mobo.

How can I access IN STOP without remote control?
Thank you

[Malva]

when programming the flash, did you do the verify procedure?

Yes, I also read again the chip and verified the dump

[lotas]

I am unable to find the EEPROM Chip on my mobo.

EEPROM: AT24C256C (IC102)

[Davi.p]

do not expect much from a different model board, check also the 3,3v on the spi..

[lotas]

If there were no 3.3v, the motherboard would not turn on at all.

[Davi.p]

both ir receiver and spi flash can be fed by 3,3v, so an overload of 3,3 v can turn off the flash and so the entire tv..