LG OLED55A1PUA

[Diah]

again wrong... please don't write some things wrong harm user TVs.
when you add R to zener diode it calculated as following R= source V - Zener limited V output( divided on / currents ..
you have in this case 7-8V and the output let say 4V. ... so you will calculated the R... but in this case after PSU turn on the 7.8V will go high to 12V... so yours first calculation will be wrong . this harm the rails. this why stepdowner or regulator in this case used.. as it will always have same out put even the input goes high... hope you learned some things now.

zener circuit can used only at stable known VDC source... not for changeable source. big PUNKT

[Diah]

ok, to clear up any misunderstanding this is where I am at right now, I did not remove power supply board but decided to give this a go one more time. I plugged the main board back into the power supply board and now all voltages ARE present 🙄as listed, including T-CON & OLED on power supply board. I have NOT reconnected the T-CON or the OLED yet.

If there is an issue with either one (will do one at a time) What should be monitored when doing this? I would presume the corresponding connector for supply voltage of each on the power supply board?🤔 If one or the other is 'bad' what should happen to indicate that?


Update - I left power on & just went back to check voltages on the OLED & T-CON connectors 10 mins later and both are now at 0V. Does this TV go into a sleep mode automatically?

i would suggust dont play with power boards at all as i i think its fine.
put every things ( all socket in place..... only disconnect the second LVDS between the MB and T-CON... its the down side when you look on the t.con turn on... give time and tell if yours audio optic port lit red

[repair-it]

Did as you suggested, turned set on, monitored voltages at T-CON & OLED connections on PSU for aprox 5 minutes, voltages held, but no optical(red) visible. Does this indicate a bad main board or could it be a T-Con issue?

[Diah]

Did as you suggested, turned set on, monitored voltages at T-CON & OLED connections on PSU for aprox 5 minutes, voltages held, but no optical(red) visible. Does this indicate a bad main board or could it be a T-Con issue?

if you don't have lg service remote... buy one

[Davi.p]

And so what? why don't you put your calculation here? Are you able? Suggested diode holds around 200mA..

[Davi.p]

Can you post a very (i mean VERY!) bright picture of main.board without heat sink?

Further.. it's time for the screen test, search recent oled discussions on how to..

[nomoresonys]

I ask the staff on the knees, is it not possible to send away this element, Nomoresonys? It is ten years or more he is 24h/24 here to mislead solutions with his same very low knowledge, and also criticize others, he is the worst element of this wonderful site, and the most present!

PS: the solution in my post #17 is SIMPLE, WORKING, TESTED..

PPS: for the zener, can be used a 1n4732= 4,7v

This from the pu nk who wrote in a post that he wished that I would get covid 19 and die, real nice guy. LOOK here you have been trying to get people to ruin their tvs with your little "experiments" for as long as I have been here, your the RUDEST MOST OBNOXIOUS individual there ever was, you have VERY limited knowledge. When a real tech like Diah points out your mistakes that can ruin a tv, you get all defensive and start insulting everyone, you need to quit embarrassing yourself with this behavior. This putz had the same thing to say to Budm when he pointed out davi pees harmful "experiments" This guy IS a virus.

[Davi.p]

never seen.you providing a solution here, maybe i've been unlucky and i don't have seen it? i don't think..

anyway, chats are enough, demontrate post 17 is wrong and i'll stay shut and quit the discussion, i suppose you never tested it before posting your sentences, otherwise stop cheating this thread..

[nomoresonys]

davi pee, fixing electronics is like a doctors Hippocratic oath...FIRST DO NO HARM, you need to keep your GUESSING and EXPERIMENTS confined to your location, this is a repair forum, people are trying to fix things, NOT make them worse.

[Diah]

And so what? why don't you put your calculation here? Are you able? Suggested diode holds around 200mA..

..

[Diah]

Did as you suggested, turned set on, monitored voltages at T-CON & OLED connections on PSU for aprox 5 minutes, voltages held, but no optical(red) visible. Does this indicate a bad main board or could it be a T-Con issue?

by removing the second LVDS as i mentioned before and you have the TV power on and remain on.... mean we have issue on T-CON or Panel... because this disconnected LVDS transport the SOS signal from T-CON firmware to the MICOM on the Mainboards which it act on this SOS and order the PSU to turn off.

but you said the Optic didn't lit red--- mean the MB went to sleep mode which we can wake it up by USB stic with Movie on it... or air mouse / USB mouse..... or also LG service menu. to send Power Only
sorry i will not response any more on this Topic... as it seem again child game start over here. good luck

[nomoresonys]

No it's not a childs game, I just pointed out pees shortcomings and he didn't like it.

[Davi.p]

So what is 400mA? Let's suppose 100mA the Iz-max, Rs=(Vout-Vz )/Iz; Iz=(Vout-Vz)/Rs=(12-4,7)/10k=7,3/10k=93uA... so where is the danger? You escape?

[Diah]

So what is 400mA? Let's suppose 100mA the Iz-max, Rs=(Vout-Vz )/Iz; Iz=(Vout-Vz)/Rs=(12-4,7)/10k=7,3/10k=93uA... so where is the danger? You escape?

are you dum or stupid.... one like you will never admit his wrong.... Vs in this OLED set are changeable... so end Value of R will be changeable too..... this why never never use this way to test PSU. if you have stable V in then will be fine after calculation.

[Diah]

No it's not a childs game, I just pointed out pees shortcomings and he didn't like it.

of sure its not about you.

[Davi.p]

12VM cannot rise over, so where is the damage? 7v or 12v the result is the same 4,7v , the Iz is same far far over 100/200mA.. am i stupid?

[Diah]

12VM cannot rise over, so where is the damage? 7v or 12v the result is the same 4,7v , the Iz is same far far over 100/200mA.. am i stupid?

yes you are.... do it on your own 1400 $ TV .... don't ask users to harm their set.

[repair-it]

by removing the second LVDS as i mentioned before and you have the TV power on and remain on.... mean we have issue on T-CON or Panel... because this disconnected LVDS transport the SOS signal from T-CON firmware to the MICOM on the Mainboards which it act on this SOS and order the PSU to turn off.

but you said the Optic didn't lit red--- mean the MB went to sleep mode which we can wake it up by USB stic with Movie on it... or air mouse / USB mouse..... or also LG service menu. to send Power Only

This is my first time working on an OLED TV so it is a learning experience for me. I connected USB mouse, monitored T-Con voltage when connecting power, then powered up. It remained @ 12v until it went into sleep mode. Mouse had no effect after in sleep mode. LVDS lower cable disconnected entire time, no optical LED the entire time. I ordered a Service Remote, but unfamiliar with how it 'could' help. The TV is only 2 years old.

[Davi.p]

Nothing. 2 flat braingraphs, cannot continue with them.. hope good luck to the OP..

[Diah]

This is my first time working on an OLED TV so it is a learning experience for me. I connected USB mouse, monitored T-Con voltage when connecting power, then powered up. It remained @ 12v until it went into sleep mode. Mouse had no effect after in sleep mode. LVDS lower cable disconnected entire time, no optical LED the entire time. I ordered a Service Remote, but unfamiliar with how it 'could' help. The TV is only 2 years old.

MAN. you did the usb or mouse while you have the second LVDS connected i each the MICOM and the set will turn off... if the set will turn on with out SOS the serice remote Power only will pass it... however i will write now in detail for you to test the PSU and T-CON and panel all together.
test one... ecery things connected.. only the OLED socket No 2 from power board disconnected.... tv remain ion or not.... if remain on... panel defect we can try to handle it later...... if rge same issue turn off.... much likely T-CON fault we do the next test..

disconnect the socket from Power boards and Main boards... disconnect the 2 LVDS between T-CON and Main boards
noe this are important.... i wrote before... take only one wire from 12VM 12V which read 7.7 at STBY.. connect it to it place at Main boards socket...... on main boards search after 3.3V rail conect wire to the point you found... at end of ithe wire connect 1K Ogm R... and the end of the R cjumber it to the three points i market before... power_on Tcon_on and DRV on-

plug the tv in wall you should have T-con and OLRD B on them and screen will show color complete or disrupted