Re: Vizio P42HDTV10A Flickering Screen

I just got my ysus back from coppel tv. Looks like they replaced two of the large transistors where the buffer connects. I now have picture but there is a faint rgb noise covering the entire picture.

Any ideas?

-Bill

Re: Vizio P42HDTV10A Flickering Screen

It's been a while and I'm finally getting back to this project.

The adjust boards tested fine out of circuit so I replaced them. Next I removed the Top Y-Driver board and the VY issue disappeared. A nice stable 200v. The driver board is mostly ICs and the few caps it has look normal.

Should I replace this board? or is there some more digging I can do?

Thanks,

-Bill

Re: Vizio P42HDTV10A Flickering Screen

I finally was able to remove the VY Adjust and VSC Adjust boards. I went ahead and removed both so I could compare them. I found the key to desoldering the boards was a larger tip, 800F and flux. The two pins that go through the large copper plane are still problematic.

I couldn't find an cap issues. I even removed c20,c25 just incase something was throwing off the in-circuit reading. I was getting an off reading from the FET (Q20). It wasn't shorted but differed from the VSC board. I removed it so I could better test it but fired...

Re: Vizio P42HDTV10A Flickering Screen

@awyatt2
I scoped my power supply and the Va and Vs looked clean so I doubt that is the problem.

I didn't have much time this past weekend but I did manage to trace out the supply to the -VY Adj. Both the -VY Adjust and VSC Adjust are feed by Vs. I attempted to remove the board but apparently my desoldering skills suck. The best I could do was turn the solder to a soft putty which was not good enough to suck it off. Even with my iron at its hottest, 900F, I was only burning the PCB. I've heard some people mention using chipquik...

Re: Vizio P42HDTV10A Flickering Screen

Thanks PlainBill this was exactly what I was looking for and I believe you posted the LG TV Plasma Training Manual in another thread which was very helpful for understanding the big picture.

I took some measurements and now I'm thinking I have a power issue on the ysus and not a ipm issue.

Here is what I found
[CODE]panel (measured)
Va 60 (60.0)
Vs 184 (184.7)
Vsc 120 (120)
Vy -200 (242-260 unstable)
Vzb 100 (100)
5v (5.09) [/CODE]

It appears...

Re: Vizio P42HDTV10A Flickering Screen

Thanks, that was my thought when I heard the ysus ticking but I wanted to be sure. I did some more digging and found some testing procedures for the IPM here:

and here:
[URL="http://monitor.net.ru/forum/files/ipm-part-for-lg-y-sus-and-z-sus-boards_456.pdf"]http://monitor.net.ru/forum/files/ipm-part-for-lg-y-sus-and-z-sus-boards_456.pdf[/URL]

and here:
[URL="http://blog.coppelltvrepair.com/2011/04/how-to-test-stk795-518-ysus-ipm-for.html"]http://blog.coppelltvrepair.com/2011/04/how-to-test-stk795-518-ysus-ipm-for.html[/URL]...

Hello, like many I see on here I have an LG Plasma with screen issues but no issues with sound. I have a decent background in electronics but zero experience in tv repair. So I've spent several hours reading posts, getting familiar with the components, and testing. I'm still poking around but I'd like some direction from the experts.


Here are the part numbers for this set.
Vizio model: P42HDTV10A
LG Model: PDP42X32000
6871QZH056B
6871QYH048B
6871QDH117A
6871QCH077C
6871QRH068A
6871QLH059A

Symptoms:
Screen is...