LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

[goldbird78]

I have a 60PM6700 that turns on but with no picture. I am sure I have traced it down to a bad EBR73710601 upper buffer board. All power supply voltages were bang on to both the ysus and zsus board. When both buffer boards were hooked up I could hear the ysus board "buzzing" on and off every 2 seconds and both VSC & VY voltages were jumping very erratically. I Disconnected the bottom buffer and same thing. Disconnected both buffers now VY has 185 VSC 0. I hookup the bottom buffer and disconnect the top and same VY has 185v and VSC 8.3V but I now I get some pixelated image on the bottom of the screen ? What you think, Shorted upper buffer ?

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

I also did a continuity test on the buffer ribbon terminals and it does appears there is a couple shorts on the upper board.

[mmartell]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

Check the joints under the transformers on the ysus before replacing the buffer.

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

Will do. Thanks

Check the joints under the transformers on the ysus before replacing the buffer.

[tom66]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

You said VSC of 0V with the bad buffer removed, I would recheck, as would expect around 150V. There may be another fault...

[R_J]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

I think the VSC passes through both buffers, If one is removed you may not be able to measure it.
I believe it enters the upper buffer, passes through p153, then to p152 to the lower buffer

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

I think you may be correct. I found the below thread with the exact same problem.

https://www.badcaps.net/forum/showth...3712701&page=2

I think the VSC passes through both buffers, If one is removed you may not be able to measure it.
I believe it enters the upper buffer, passes through p153, then to p152 to the lower buffer

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

Surprisingly all solder joints look good, I dont think this TV has many hours. When I pulled the back off there is very little dust.

Check the joints under the transformers on the ysus before replacing the buffer.

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

Hi Tom, See page 2 on the link below......This guy really knows his stuff.....

"On this particular set it appears that Vsc is passed between the buffer boards by the Y-sustain. So indeed with a missing upper buffer you will not read Vsc. This is NOT the case for every plasma. They do things differently on different sets.

You need, in this case, to check Vsc with all boards in. If the voltage on the big 10R resistor is LOW after this, you may have a shorted buffer"

https://www.badcaps.net/forum/showth...3712701&page=2

You said VSC of 0V with the bad buffer removed, I would recheck, as would expect around 150V. There may be another fault...

[R_J]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

With just the one board in you should be able to measure the voltage on that R279 10ohm5w, it might check a bit high due to no load but I think it should be close.

[tom66]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

Hi Tom, See page 2 on the link below......This guy really knows his stuff.....

"On this particular set it appears that Vsc is passed between the buffer boards by the Y-sustain. So indeed with a missing upper buffer you will not read Vsc. This is NOT the case for every plasma. They do things differently on different sets.

You need, in this case, to check Vsc with all boards in. If the voltage on the big 10R resistor is LOW after this, you may have a shorted buffer"

https://www.badcaps.net/forum/showth...3712701&page=2

Nah I wouldn't trust a word that guy says I've heard he doesn't know shit about TVs.

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

151.2v

with just the one board in you should be able to measure the voltage on that r279 10ohm5w, it might check a bit high due to no load but i think it should be close.

[R_J]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

So you have a bad upper buffer and the lower works partly because it is missing the VSC, when a new upper buffer is installed I suspect the whole picture will be o.k.
Famous last words

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

Have one coming in from Quebec $50 shipping included.

[goldbird78]

Re: LG 60PM6700 no image. Bad EBR73710601 Upper buffer board ?

problem was the upper buffer board.....nice cheap fix on this one.