Service Menu for 50LN5750

[neilc6]

I was repairing the backlight on a 42LN5700 and forgot to remove the screw at the component connectors. I ended up pulling out the terminal block. I was able to unsolder the pins, push them back in and resoldered the block. Quick test and everything was ok but when I buttoned everything back, the TV wasn't booting (no DRV_ON signal) and front LED was dim.

I had a main board from a 50LN5750 and it appeared to be an identical match other than part number. I popped it in and TV works fine. Though I renamed the TV in the menu, the LG remote app still detects it as the 50LN.

Looked for online instructions to get into service mode and didn't work. Tried pressing both OK on side button and remote simultaneously and MENU button as well.

Maybe it's a sign I shouldn't mess with it since it is working. Bonus is that it will now support a magic remote.

[neilc6]

Re: Service Menu for 50LN5750

I am going to answer my own question here. To get into the LG service menu, you can download an app if your phone has an IR blaster or you can buy a service remote (Aliexpress, Ebay). Buttons are IN START, ADJ, and IN STOP (performs factory reset). Use 0413 as a password or google for other possibilities.

Looking at the options in the ADJ menu shows an option for default backlight for ECO mode (70) and a 75% Backlight option. Wondering if 75% is an option to reduce the maximum backlight or to set the default backlight to 75%. Don't want to tinker too much with service menu options.

[budm]

Re: Service Menu for 50LN5750

It looks to me it the backlights will be at 75% if you set the TV to ECO (Economy) mode in the OSD User setup menu, but if you set to I.E. VIVID mode it will probably drive the backlights at 100%.

[neilc6]

Re: Service Menu for 50LN5750

They were 2 separate options. One is likely the default backlight level for eco mode, The other just says 75% backlight. There is a youtube video but the backlight options are slightly different.

[budm]

Re: Service Menu for 50LN5750

I wonder if that is updated FW that LG puts out to reduce the backlight so the maximum drive will be at 75% (100 on the User menu).