LG 55UH6030 backlight issue

[EazyBone]

55uh6030 LG no backlights . Edgelit tv

This TV turns on and shows picture. Everything is fine there so I'd assume it rules out the tcon/main/panel.

The problem is, they don't turn on. LED tester lights up each side at 165Volts

The voltage comes up to 335v on each side but they don't light up.

Anyone experience something like this? I could assume the LEDs are bad but I feel like maybe might have some insight on this.

Main cap hits 401v steady

[vinceroger69]

Re: LG 55UH6030 backlight issue

Have you measured the bl on pin on the connector

[EazyBone]

Re: LG 55UH6030 backlight issue

Have you measured the bl on pin on the connector

Assume you mean the 335v running to them? Each channel has that. Unless you mean something different

[EazyBone]

Re: LG 55UH6030 backlight issue

Anyone got anything to make me think on this? I don't see an issue but PSU aren't turning on LEDs.

Full picture, so PSU or bl related.

[Diah]

Re: LG 55UH6030 backlight issue

Anyone got anything to make me think on this? I don't see an issue but PSU aren't turning on LEDs.

Full picture, so PSU or bl related.

put yours Dm probe on each group LED+& - then plug it in wall record yours high and low V. same way do it but this time between TV chassis and LED+ of the groups..

end result compare the reading

[EazyBone]

Re: LG 55UH6030 backlight issue

Thx will report back with that. I thought I did that and it was the same but I'll recheck. Thx

[EazyBone]

Re: LG 55UH6030 backlight issue

Chassis and LED+ turn on TV, stby goes to 181v and pretty steady
Hit power jumps to 324 within about 2 seconds, climbs up to 335.5 in about 10 seconds and is actually fluctuating between 334.5-336.5. slowly fluctuating but always that range

Between+ and - LED stby goes to .972v and power goes quickly to 1.7v and about 10 seconds goes to 2.3v and hovers around 2.28v and 2.33v slowly fluctuating.

[Diah]

Re: LG 55UH6030 backlight issue

BL issue

[EazyBone]

Re: LG 55UH6030 backlight issue

Sounds good. They were 9$ so I ordered

[Diah]

Re: LG 55UH6030 backlight issue

Sounds good. They were 9$ so I ordered

well regards to yours measurements report you have open at LED... it could be too the socket joint down side the screen LOL

[EazyBone]

Re: LG 55UH6030 backlight issue

What tells you it's open? Because of the fluctuating voltages?

[Diah]

Re: LG 55UH6030 backlight issue

What tells you it's open? Because of the fluctuating voltages?

No load.. in this cases we need start from checking the PSU downside of the BL circuit if there one of the SMD R for current limit Open.

[EazyBone]

Re: LG 55UH6030 backlight issue



No load.. in this cases we need start from checking the PSU downside of the BL circuit if there one of the SMD R for current limit Open.

So diah, incorrectly diagnose here. Learning experience for me, changed the LEDs problem still exists. There is a pin on the PSU labeled MS and is getting zero volts. I believe this is a MB sent signal to turn BLs on. I found some random post of a guy jumping MS to turn on BLs with pw on. I disconnected the single pin from MB and jumped it with some, and sure enough BLs came on with picture. All was perfect. So there is some main board issue.

Is anyone familiar with this MB BL signal issue? I read briefly this could be an issue in another thread but no mention as to how it was fixed or where to get the information

Edit, not sure where my pictures went, maybe this forum reset lost them. I'll post some in a bit

[Diah]

So diah, incorrectly diagnose here.

we are sitting behind pc screen... all judgments depend on the information and photos the threat owner show us...
at post #2 vinceroger69 asked you the points you talking just now on it.LOL

[EazyBone]

we are sitting behind pc screen... all judgments depend on the information and photos the threat owner show us...
at post #2 vinceroger69 asked you the points you talking just now on it.LOL

There is no BL on connector, I asked what he meant and has no answer. Think you taking this the wrong way, and not sure where my pics went, here is some more.

PSU with MS, shows zero volts. Don't know what MS stands for


I am trying to trace the line, not sure if anyone can help but the path I see so far is pic 4. The MS pin starts and I run backwards to that little transitor( or whatever component) and the continuity ends there. The other side of the transitor corresponds to leg 5 (of bottom row) on 100gea chip. Then I can't trace it leaving the chip at all. No beep beep on any leg after this chip.

All I got so far, any input appreciated

[Diah]

MS are !MICOM Signal" IC3000 are the "MICOM" .on LG MB platform.. same to OLED TVs.. its programmed within Firmware. and it could get defect in way of cut T-CON 12V or BL signal too.. try first with IN_STOP... it may come back to life..

[vinceroger69]

There is no BL on connector, I asked what he meant and has no answer. Think you taking this the wrong way, and not sure where my pics went, here is some more.

PSU with MS, shows zero volts. Don't know what MS stands for


I am trying to trace the line, not sure if anyone can help but the path I see so far is pic 4. The MS pin starts and I run backwards to that little transitor( or whatever component) and the continuity ends there. The other side of the transitor corresponds to leg 5 (of bottom row) on 100gea chip. Then I can't trace it leaving the chip at all. No beep beep on any leg after this chip.

All I got so far, any input appreciated

Just seen this post im still learning myself bl on is usually the singnal too turn them on hence i mentioned checking the voltage i have never seen a lg marked with ms so no idea until now what that meant the main thing is your narrowing down the fault and for the cost of the backlights it should make the tv last for a good few more years .

[EazyBone]

MS are !MICOM Signal" IC3000 are the "MICOM" .on LG MB platform.. same to OLED TVs.. its programmed within Firmware. and it could get defect in way of cut T-CON 12V or BL signal too.. try first with IN_STOP... it may come back to life..

The more I learn

So I power on with service remote, tv powers on. Is unresponsive to any remote clicks. The TV shows picture and everything like normal but besides the power button nothing else works. I've tried 3 different remotes and the service menu, also the button on bottom of tv i believe swivels to change volume or channel (maybe) and it does nothing also. But it works as a power button.

Suggestions?

[Diah]

The more I learn

So I power on with service remote, tv powers on. Is unresponsive to any remote clicks. The TV shows picture and everything like normal but besides the power button nothing else works. I've tried 3 different remotes and the service menu, also the button on bottom of tv i believe swivels to change volume or channel (maybe) and it does nothing also. But it works as a power button.

Suggestions?

so did the IN_STOP bring back the micom sending the lost signal to BL?
it sound to me you pressed on service remote Power Only.... this is limited function must pressing exit then turn off so you can back to normal state

[EazyBone]

so did the IN_STOP bring back the micom sending the lost signal to BL?
it sound to me you pressed on service remote Power Only.... this is limited function must pressing exit then turn off so you can back to normal state

No like, only power works on the remote. On any of the remotes, I have unplugged them, replug, tried combinations etc. no other button works except power. Including service remote. I'll give it a try again but odd