Just picked up a 55 inch LG 4k OLED for $50!

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

I know. That path of ELVDD makes the drivers toasty already with the logic cycles that they already have to produce anyway. Wondering if that is what eventually led to the other panels demise.

I'm going to test some more on this board. I noticed the not so handy rs232-in-a-headphone jack. Wonder if this is how LG writes to the board to reload the logic or reset it when it fails like this situation. Of course none of this I have.

The USB ports have no power in this Present situation

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

I decided to take the guts from this busted screen tv and swaps them onto the defective line screen for shits and gigs since I had them anyway. I forced ps-on, 12v on and drv-on. Even thou mainboard is defunct, I get this andf every time I power down and plug back in, the screen changes a bit. Still have a dead mainboard thou.

P.s. Happy New Year everyone! Your a great bunch of people!

[Davi.p]

Re: Just picked up a 55 inch LG 4k OLED for $50!

So finally is this a good purchase or not? I think starting a new technology experiment with a giant tv it's a risky business, i maledice myself when i have take this 60 inches without testing it well before buy, now is sitting in the garage to take dust.

Excuse me, "freak after 8 PM" o "freak after 8 AM"? :-)

[budwich]

Re: Just picked up a 55 inch LG 4k OLED for $50!

sorry but I didn't read thru the whole thread ... but have you checked the conditions for where the 3.3v gets generated to see if something is stopping it generation? If so where have you checked?

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

I agree however I have not sunk a tremendous amount of money into these TV's and knowing that I have one that is the most likely candidate for repair since it has a brand new screen and it I'm not worried about making my money back.

However is the broken screen one that I salvaged the panel from the original TV I'm gonna use as my Guinea pig so I don't screw up the good one.

[Davi.p]

Re: Just picked up a 55 inch LG 4k OLED for $50!

Hi, can you pubblish Shopjimmy's pictures of the board? 'Cause in Italy is not visible, i've seen a srv.manual of a recent Philips tv, the 3,5v that came from PSU became 3,3v and 3,37v by 2 linear regulators, so it's possible that a regulator ran away by your eyes?

[budwich]

Re: Just picked up a 55 inch LG 4k OLED for $50!

it would appear from the documents that you posted that somewhere there is an unenabled regulator of "type" TPS54427.

[Davi.p]

Re: Just picked up a 55 inch LG 4k OLED for $50!

OK seen budwich i thought there was schematics (i have asked it), so i've seen them..
The TPS54527 transforms 12v in +3.3V_NORMAL that also lights up a led,
but this is unactive until MICOM don't set RL_ON "ON", IC3000 is a MICOM i.e. standby cpu, it controls IR & KEY board and there's a reset switch SW3000 (how it works?). You can try this reset or there's something that blocks this Micom to switch everything on, maybe standby firmware corrupt or need a connection to a pc for Micom debug through P3000..

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

You read my mind and I was just about to post about the SW3000. This enables MICOM RESET AND MICOM DEBUG.

This is part of the p3000 connector. , It looks like LG uses this for something they would plug a jig into.
However I have pressed the button and it eliminates the power light or the flashing I've held it down I pressed it nothing happens when I release the button it goes back into his present state

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

It would appear that MICOM is powered or at least the standby section for MICOM IC3000

Between pins 2 and 4 of p3000, I get 3.5vdc when SW3000 is pressed.

On IC3000 I have 3.5vdc on pin 48

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

This is interesting

P102 IS OBVIOUSLY an LG proprietary jig. Some TX RX signals there. Maybe for programming MICOM reset?

[budwich]

Re: Just picked up a 55 inch LG 4k OLED for $50!

not sure but have you checked all the "conditions" associated with the regulator to see what state it is in (what pins are getting what). If everything looks "reasonable", then just enable the regulator with a battery and see what happens. :-)
Of course, you might have to isolate the enable pin from the exiting circuit depending on what the path looks like (resistance wise or otherwise).

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

That would be a good theory was kind of what I was thinking but I'm not sure where to enable.

However I did come across this portion of the schematic and this shows what SW3000 is doing.

Surprisingly pin 36 for RL-ON is energized. 3.5v on IC3000

[Davi.p]

Re: Just picked up a 55 inch LG 4k OLED for $50!

I don't see the relationship between a bad screen and a a bad micom...
Have you got a Scope? Can you probe the signals at P4100 (VS IR-key board)?
Voltage regulators doesn't affect anyway, here we have a Micom directly powered by PSU bd (pin VDD), it doesn't power up the system.
The eeprom programmer that i've mentioned earlier is capable of reading-writing many MICOMs.
Freak, how can you fault find with a cellular?? Is not uncomfortable? I think a fixed pc is better...

[budwich]

Re: Just picked up a 55 inch LG 4k OLED for $50!

That would be a good theory was kind of what I was thinking but I'm not sure where to enable.

However I did come across this portion of the schematic and this shows what SW3000 is doing.

Surprisingly pin 36 for RL-ON is energized. 3.5v on IC3000

you jump too fast. The first check is to look at ALL the pins on the regulator to see if the conditions being supplied to it are in tact. Then would be to watch for the enable and see whether it shows up ever. IF not, you can probably just wire to the pin a battery source temporarily.

my first guess would be that the regulator was taken out by something as it has a current limit of 5a.

[tom66]

Re: Just picked up a 55 inch LG 4k OLED for $50!

90% sure you have bad firmware, board is failing to boot because of this.
Unless you have correct firmware, it'll never boot.
You might find a UART debug port on the board - not the user one - that dumps the Linux bootup messages.

It's what kills most of these main boards, corrupt firmware either due to application bugs, or more likely, flash memory failure.

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

Yeah it appears that maybe this firmware is bricked after all. Kind of summed it up after I see IC3000 trying to energize RL-ON. Now the big question do you think I would be able to reflash somehow?

Interesting that it seems to somehow flaw the firmware by reboots consecutively when it recognizes something wrong with the panel

[budwich]

Re: Just picked up a 55 inch LG 4k OLED for $50!

not sure I would lay the blame on firmware especially since you indicated that you "swapped the guts" of two tv's. That sounds rather unusual.

[Davi.p]

Re: Just picked up a 55 inch LG 4k OLED for $50!

Check the S.manual for recovery modes or how to enter S.menu then you will see if it's a problem related to a faulty screen state memorized.

[freakaftr8]

Re: Just picked up a 55 inch LG 4k OLED for $50!

Nothing at all in service manual about reset code or recovery. That's why I'm stumped. LG apparently has to physically come to your home with new boards when this happens after a replacement panel. As read from the AVS forums on this particular model.