LG 60PC1D-UE picture messed up

[tom66]

Re: LG 60PC1D-UE picture messed up

This looks more like a control board issue to be honest.
I recall having an issue with an old TV based on a 42V5 panel which I eventually pinned down to the ctrl board but decided it was not worth repairing due to the age of the set.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

thanks tom

i would live it if it was just cintrol board issue......inrxpensive part


the goofiness and randomness with no pattern is what concerns me

[shelby5041]

Re: LG 60PC1D-UE picture messed up

i got tv couple weeks ago....owner said good pic but after 15min pic would distrt

it did kind of that when i tested it .....could get a perfect pic then randomly distort

now piic wont go perfect and its more random than before.......last week puc was perfect on bright scenes....but on dark scenes it would distort

its not like that now......no more good pic

[shelby5041]

Re: LG 60PC1D-UE picture messed up

hi could someone help me out with testing y buffer for short on this plasma

is there a universal procedure that will work on all y buffers? if so what is it?

i have tested other buffers before but vidoes would show exactly which pins to touch.....but on this model board i do not know which pins to touch

when i rake across the output to panel pins where should the other meter end be?

see photo of actual y buffer i have

[shelby5041]

Re: LG 60PC1D-UE picture messed up

i tried putting a lead on the large copper pad on the bottom assuming that was a ground and then raked the other lead across all the buffer to panel connectors but that didnt work....was that an incorrect method to test for short?

[tom66]

Re: LG 60PC1D-UE picture messed up

The silicone goop on this model makes it hard to test the buffer boards. Either way, I doubt your fault would be caused by a bad buffer board. The buffers are responsible for vertical addressing. When they fail, too many pixels effectively get programmed with data, so you get line bleed like this:




Essentially, horizontal pixels are bleeding together into one combined column and the panel is not fully discharging properly.

Occasionally Y-buffer boards can cause missing lines, or interlacing, but not in the way you are experiencing.

[maleksa]

Re: LG 60PC1D-UE picture messed up

Just to share my 2 cents worth...

I had a similar problem (except that the picture I was getting was a lot worse) on my LG 60PA6500. I found that the problem was due to bad soldering and a dirty Y-Sus board (I did not clean the board after soldering). The problem went away when I installed a fresh Y-Sus board.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

thanks tom and maleka

tom could u tell me which pins i would set meter on.......for testing y buffers....i know goop....just want to learn what to put meter on...

[tom66]

Re: LG 60PC1D-UE picture messed up

thanks tom and maleka

tom could u tell me which pins i would set meter on.......for testing y buffers....i know goop....just want to learn what to put meter on...

Well you'd need to test to the pins on the goop. Which means you need to remove the goop, and I wouldn't recommend doing it on these as it's there for isolation. (You can put it back of course - but it's expensive stuff.) So unfortunately you cannot do the test.

Anyway, as I said I'd be surprised if this was a Y-buffer fault, it's looking more like a fault with the digital processing stuff, like the control board, but I cannot be certain. It's a very old set, and uses some different technology to the modern sets I'm more familiar with.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

assume there is no goop

what pins wiuld i put meter on

im trying to learn for all y buffer testing

[Doc38343]

Re: LG 60PC1D-UE picture messed up

assume there is no goop

what pins wiuld i put meter on

im trying to learn for all y buffer testing

Y-buffers may not go to chassis ground. I think what your asking is how to rake the pins where the ribbon connector plugs in. To locate the ground plane for those buffer IC's you just need to look closly at the board traces and you can see the isolation. in many cases the ground plane (being larger portions of the traces) can be seen. I also tested mine by finding a IC chip and looking up the datasheet then locating the ground pin and I could see thru the solder mask where it was. Also note there are some SMD caps and most of the time one side of those is to the ground plane. Remember when your on a buffer board some portions may go to chassis ground and some may be isolated from it. You need to find the isolated one to do the buffer pin rakes. Also one buffer chip can control half of a ribbon connector above or below it. if you hear a short you will need to look at the tiny traces that run to one chip or another.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

thank u


can u look at the buffer board pics i posted and tell me wherr a ground would be to test the buffer raking pins

[shelby5041]

Re: LG 60PC1D-UE picture messed up

ll rephrase it

to test buffer ic shorted where would i put meter leads

one lead would rake the pins on connector to panel and other meter lead goes where?

[Doc38343]

Re: LG 60PC1D-UE picture messed up

thank u


can u look at the buffer board pics i posted and tell me wherr a ground would be to test the buffer raking pins

The brass looking test point by R107

[shelby5041]

Re: LG 60PC1D-UE picture messed up

thanks ill try it

[shelby5041]

Re: LG 60PC1D-UE picture messed up

ok i put lead on brass pad near r107

and other lead raked pins on each of the 6 connectors and i get continuity on 3of the connectors

so ics shorted?

[tom66]

Re: LG 60PC1D-UE picture messed up

The ground point (actually "floating ground" as it is not a true ground) is the large copper pad with two bolt holes.

The high point (VSCAN+VFG, or floating VSCAN) is the smaller one.

Test between high and ground, and ground and each output pin.

[shelby5041]

Re: LG 60PC1D-UE picture messed up

thank u

should have no continuity between ground and any output pin....correct?

[shelby5041]

Re: LG 60PC1D-UE picture messed up

and tom.....from my photos how tv is acting....would you rule out x/z suatain issue?...in addition to ruling out y buffers?

i ordrrrd a y last week.....if not y..ill order a logic

[shelby5041]

Re: LG 60PC1D-UE picture messed up

fyi thr buffers i testrd werr ones i bought on ebay last week....they appear to be shorted.