LG 50PS60 UA Plasma

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

No, sir. I am using the test tab for -Vy on the Y-Sus board using the red electrode, and the ground electrode attached to the chassis of the television. And, i'm pressing the red electrode to the positive side of the Vsc resistor. Should I measure directly across the resistor?

I'm sorry to be such a pain, Tom.

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I'm such an idiot. I was misunderstanding the whole principal of testing the Y-SUS board. I misread your instruction, and was reading just the positive mark on the resistor for the -VY and the VSC on the Y-SUS board. I was grounding the ground probe to the chassis, and only using that positive side. So just now, I went back and took more readings, the way you described it once again, and you're correct. With the Y-Buffer boards not attatched to the YSUS, the YSUS stabilizes, and gives me 150 volts on the VSA, and 179 volts on the -Vy. Just as the sticker says it should. But when I plug the upper Y-Buffer back to the Y-Sus, voltages once again become unstable.

Please forgive my ignorance. I'm assuming you're going to suggest replacing the upper Y-Buffer board.

My humble apologies,

izzy

[tom66]

Re: LG 50PS60 UA Plasma

No worries... I'm going to suggest replacing the upper Y-buffer board since it's $40 for two on eBay, I'd just get both upper and lower to remove any doubt.

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

Is it ok to use used parts?

Tom, you have been a very patient man. Trying to troubleshoot a television from across the pond is taxing at the very least. YOU, sir, are a gentlemen, and a scholar.

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I received my new parts yesterday! I installed them, and I have good news and bad news. The good news is, my display is once again illuminating a No Signal prompt. However, it's still in the distorted blue I described before, like the YouTube video I posted in the first comment.

So, I went back, and rechecked my readings:

-Vy = 180 (sticker says 180)
VSC = 149.6 (sticker says 150)
Vs = 194 (sticker says 198)
Va = 58.8 (sticker says 68)
Zbias is 104.5 (sticker says 105)

Should I measure something else?

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

By new parts, I mean Y Upper and lower buffer boards.

Here's the youtube link to what my display looks like: https://www.youtube.com/watch?v=3vZk3ZvofMc

[tom66]

Re: LG 50PS60 UA Plasma

So, the fault has not changed? The -Vy and Vsc are stable now?
Double check that Va...

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

yes they are! you were correct about the buffer boards! If I lived in the UK, I'd just bring it to you!

izzy

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

But I enjoy learning to work on it, also!

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I went back to double check the Va, still says 58.8. And steady

[tom66]

Re: LG 50PS60 UA Plasma

yes they are! you were correct about the buffer boards! If I lived in the UK, I'd just bring it to you!

izzy

...? I am confused? Has the fault changed?

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I'm sorry, no, the fault hasn't changed. When the fault first occurred, my video on the TV was blue and grainy, like the video I posted. Then, after a day or so, there was no video, and the YSus board started surging. Now, the Ysus is stable, with the new Y buffer boards installed, and I now have video again, but the blue grainy appearance is still there.

I'm sorry for the confusion! And to think, I'm a radio personality in real life! lol

izzy

[tom66]

Re: LG 50PS60 UA Plasma

Ok, and -Vy/Vsc are stable?
Is Va marked 58V or 68V on the panel?

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

the panel has it marked at 68 volts. Tom, you're really a good dude for having this forum, thank you.

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I've been combing through the forum, I can't find another board to test. Anyone have any ideas?

izzy

[tom66]

Re: LG 50PS60 UA Plasma

Sorry, missed your post.

68V is very high, are you sure that is not the maximum rating? There is a max, and a nominal (probably 63-66V)
I would try adjusting it to the nominal rating.

It's important for Va to be within about 1-2V of the rating & to not exceed the maximum 68V.

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I'll go back and look at the label again today. I'll post a picture to make sure I'm reading it correctly. You and I both know I over look things! lol

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

I went back and double checked the voltage for the Va. The sticker says 68 Volts. This is a new video of what my screen looks like. I apologize for my camera

https://www.youtube.com/watch?v=g8v0iP1eVKA

[tom66]

Re: LG 50PS60 UA Plasma

Can you check Vzbias on the Z-sustain now?
I think your Z-sustain is causing issues, are all connectors fully seated? (Only disconnect or connect them with power OFF.)

[Izzy_Reak]

Re: LG 50PS60 UA Plasma

Zbias is at 104.5, I can see why the cost to have a television diagnosed is so expensive. LOL it can be rough on you!

I double checked all the connectors, they seem snug...