LG 60v400 display problem

[drftoss]

Hi there,

New to the forum and tv repair. I have some electrical knowledge coming from Mechanical Engineering at the college level but most of my practice has been on my car.

I have been trying to read up on this problem but still have many questions so here it goes.. I just bought this 3 year old LG 60" plasma off of a buddy for cheap expecting it to be a relatively easy fix but so far I have been lost on the terminology more times than I can count. The tv turns on and I'm told the sound still worked but no display. It will respond to buttons pressed with light flashes but then shuts off again. Opened it up and took a picture, couldn't find anything loose.

I think what I'm getting out of what I've read is that people have changed their x/y/z sis and/or the main power board. What are the x/y/z sustains and how do I identify them? What can I check next? I'm hoping this is a relatively cheap and fast fix.


Thank you for any insight, it is very appreciated.

https://scontent-yyz1-1.xx.fbcdn.net...a0&oe=58076856

[ReeceyBurger123]

Re: LG 60v400 display problem

Advise do some research on google plus the forum. Read what you should add to a thread. Run the test patterns. Test voltages. Help us help you.

[Hamie]

Re: LG 60v400 display problem

Unplug the z-sus.

Turn on tv, do you get a picture?

[drftoss]

Re: LG 60v400 display problem

After reading through for a few days, i have found that the top y-buffer is usually the culprit. So firstly, i need to know which board is which? Also for the testing, I'm not sure where to pull any reads from exactly?

[ReeceyBurger123]

Re: LG 60v400 display problem

Remove the top buffer, and test for Y drive voltages like:

VSC
VY

Also test Zsus voltages:

VZB

Report back to us on what you find.

[drftoss]

Re: LG 60v400 display problem

Remove the top buffer, and test for Y drive voltages like:

VSC
VY

Also test Zsus voltages:

VZB

Report back to us on what you find.

I'm really not sure what any of this means. Should i be referring to a manual somewhere?

[Hamie]

Re: LG 60v400 display problem

What was the outcome of running the tv with the z-sus unplugged?

[drftoss]

Re: LG 60v400 display problem

What was the outcome of running the tv with the z-sus unplugged?

Still no luck on figuring out what the zsus actually is.. Or where the fuse is located and what that looks like?

[ReeceyBurger123]

Re: LG 60v400 display problem

You need to research how to test the boards, using badcaps. Load of threads on this set and other plasmas.

[drftoss]

Re: LG 60v400 display problem

No picture with the zsus unplugged. Just lines which is more than with it plugged in.

[drftoss]

Re: LG 60v400 display problem

Remove the top buffer, and test for Y drive voltages like:

VSC
VY

Also test Zsus voltages:

VZB

Report back to us on what you find.

I read you should hook a light bulb up for this test, is it okay to do without?

[drftoss]

Re: LG 60v400 display problem

With both boards plugged in: sound but no picture at all, buzzing on startup. Green light blinks 3 short times then 1 long

Zsus unplugged: sound and picture with black blotches and horizontal lines, light blinks 2 long, 2 short quickly after, same buzz

Y sus unplugged: sound but no picture at all, louder buzz from z sus and burning smell, light blinks 2 long then 2 short and fast.

Zsus fuze appears to be bad. Looks like the ceramic ones are soldered on and i have to take the whole board off to change it?

[drftoss]

Re: LG 60v400 display problem

Edit: not sure how to edit or delete my previous posts that are unnecessary..

Took the zsus board off. Noticed it's kind of black to the left of the coils and the connections on the back don't look great. Could they be the source of the problem? Can i replace them alone or would i have to do the whole board?
Thanks guys! I'm learning lots

[ReeceyBurger123]

Re: LG 60v400 display problem

Resolder them, got image as well ?

[drftoss]

Re: LG 60v400 display problem

Resolder them, got image as well ?

Just took some. They definitely look bad to me, fixable or new board needed?

Edit: just resolder the coils and they'll still work? Thought you were talking about the fuse but read again and realised..

[ReeceyBurger123]

Re: LG 60v400 display problem

Its possible that the broken could have shorted out some transistors. Best to replace the board if your not confident matey.

[Hamie]

Re: LG 60v400 display problem

You're probably not going to get a replacment zsus for this model as this is a common fault and they are very scarce. If you take a photo of the underside of the board I can show you what needs changed out.

[drftoss]

Re: LG 60v400 display problem

Damnit i thought i posted them.

[ReeceyBurger123]

Re: LG 60v400 display problem

Thats bad, fuck you Lg for such a shit design motherfuckers ! Them coils are just the start its probably took out some transistors with it, do you know how to test them ?

[Hamie]

Re: LG 60v400 display problem

OK so all igbts will need replacd here:
Plus the 2 burnt 10 ohm resistors.
(they should measure 5 ohm in circuit because they are in parallel.

Youll need to remove all the solder from the inductors that are burnt, luckily it doesn't look like much damage has been done.