Lg 60PS60 no image but pdp glows

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Thank you. Something to remember with the 60H3 series of pdp panels. Even It's the buffer boards show no shorts it does not necessarily mean that you could have an open IC instead of a shorted IC. In my case one IC On the upper buffer board Somehow went open circuit on one even and one odd line shutting down the whole panel outputs. Y sustain was inevitably fine after all.

[mmartell]

Re: Lg 60PS60 no image but pdp glows

Good job brother.

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

New upper buffer installed. Problem solved! So even thou buffer showed no shorts, output parity was an issue. Open circuit on one line driver output will cause whole panel to have issue. Must be series line driver buffers....

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Try here



Are you sure your replacement buffer is 100 percent good ?

I'm not entirely sure that's why I ordered another one even though Testing it with a DMM showed no shorts I'm skeptical. However when just the lower buffer is connected of course the picture will not be right it will be maldischarged because the data is not being sent to the bottom buffer if not passed through the top 1st, The lines are present on the bottom only for a split second then they clear up And then shows the whole bottom side of the picture being full even and odd. I am still suspecting a Y main fault, As whatever drives the even and odd outputs from the sustained board obviously has half load on it as opposed to a full load with both buffers connected

[mmartell]

Re: Lg 60PS60 no image but pdp glows

Try here



Are you sure your replacement buffer is 100 percent good ?

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Does anyone have a schematic for this model? Looking how address buffers output even and odd outputs to buffers. As I have even outputs but not odd so the screen looks interlaced.

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

So o upper buffer board somehow goes short and shuts down y drive signals to panel. Upper duffer replaces and now have interlaced screen.

Obvious has aomethijng to do with odd and even signals to panel. I have signals driving even and odd to the buffers. Still have interlaced screen. You can see the lines. Either odd or even outputs dead. New control board no help. Any ideas?

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Ok so logic board is ok. Tried another. Same result

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Could anyone shed some light on the adum1510 codec ICs on the Y main? Judging by the way that the sustained board is build it looks like these decode the signals for even in odd parity going into the buffer boards if I'm not mistaken?

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

It's almost as if it's getting even signals to the pdp but not the odd horizontal output. Of course the whole panel lights up evenly from the Z main. It's just not energizing these every other line from the y.

Definitely interlaced. I've tried just upper and just lower installed with same results.

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

OK so top buffer is replaced and now I have this dithered screen every other horizontal line is out. The whole screen is like this with test pattern enabled or connected to mainboard.

Any ideas?

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Never mind I nailed it. It was the upper buffer board all along. Somehow one of the pins on one of the output drivers had a short and obviously was muting the drive signal passed the waveform which did not show up I'm the sustain board. Oddly I had a perfect uniform Gray raster all along screen with no black lines depicting a short but somehow The buffer board was able to mute the output signal to the screen completely. Im assuming the panel was priming due to VZ bias on the Z. But was not registering the y sustain to doing anything on the panel so basically it was like dead on arrival. You learn something new every day and I have never seen this before.

The only thing that has me stumped is normally when a buffer board fails or shorts it will always affect the Y sustain. This one kept humming and buzzing along like a bird in a tree with absolutely no problem and no voltage indifferences.

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Does anyone have a schematic to the EBR55492901 ysus?

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

I can't believe for as long as I've been working on plasma TV's these small insignificant questions have been lingering in my mind. Would you think there's quite a bit of amperage being drawn across those flat FFC cables that they would just melt!?

Nonetheless if I disconnect the FFC from logic to C buffer or what LG refers to as XY where the cable carries the voltage from the Y main to the 1st buffer, That section goes Berzerk with a bunch of flashing maldiscaged vertical bars. If I disconnect the far left one I can see the flashing but it's not as predominate . If I disconnect the middle no change still blank screen.

[Andrew F. Ali]

Re: Lg 60PS60 no image but pdp glows

There should be FFCs doing the interconnection, probably about 1/2" or so connecting them together. I've never come across internal interconnections like that

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

There is power cables applied to the far left va buffer from the y main. How does this power travel to the other 2 boards if no power cables for Va travel to those too? I have always wondered this. Does that charge all the VA buffers internally inside the panel?

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Ok it's Vzb not VE on LG. Anyway. It's spot on with panel label. This is with bottom C buffers connected So disconnecting them does not change any voltages

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

Right. I meant zsus. I seriously think the panel may be culprit here. When I disconnect far left VAbuffer I can see all sorts of vertical bars flickering. Middle and left, no change.

Also IC905 on ysus is a ground tab. So that blows my theory.

[Andrew F. Ali]

Re: Lg 60PS60 no image but pdp glows

Ve-Erase voltage is generated in the Z-SUS Bd. Most panel stickers usually have NA for this voltage but it is around 90Vdc. This will not be causing your issue though. However, if it is not being generated you would see picture retention and or ghosting of images on the screen. if you could disconnect the Va buffers one at a time and see if the voltages come up then we may be able to determine if there is a COF/panel issue.

[freakaftr8]

Re: Lg 60PS60 no image but pdp glows

This Is the area that appears dead and here's the mosfet that shows no output on the tab IC905