LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper right.

[Gary_B]

I will post again with various voltages, pictures and such once I pull the back off and have a look but I thought I'd just post a quick description of the unusual symptoms in the hope that somebody will know what's happening from their own experience.

We only use our 50" LG 50PQ10 for watching computer files through HDMI.
I was asleep on the couch and woke to find the TV apparently timed out and off as you would expect after a file finishes playing and you don't shut anything off. The red light was lit and there was no sound. (normal).

I walked up and used the main power button to shut it of then turn it back on again. The light went from red to blue to red to blue VERY quickly (may be normal it always does this now and it's so brief that I am not sure that it didn't always do this) then flashed blue one time then came on steady blue. (once again I am not sure if this is what I always see on power up or not so this may be normal). After the usual delay it clicked normally but there is no picture and it made a sound that starts out high pitched for about one second then drops an octave or two and continues like that forever.

The TV reacts normally to the remote and as I said the light seems normal (I think). It does not turn off or flash any other light patterns. It does the same things exactly no matter if it has been unplugged or if I turn it on and off with the remote or with the power switch. When I play a file from the computer the sound seems normal except for the buzzing.

The sound does not seem to be coming from the speaker, when behind the set it seems to come from the right top corner. The back is still on so it is hard to be 100% sure, it may be coming from top center.

I am involved in a big project for the next 5 days and will not be able to remove the back and check any voltages or anything until Wednesday July 8th. at the earliest.

I just hoping somebody will recognize "LG plasma, normal lights and remote function. Normal click but no picture does have sound with buzzing from upper right" and can tell me what happened.

I will still want to verify with checks but I am hoping for a running start.....

Thanks all, this is a great forum, far better than most and I am into homebuilt airplanes. Those guys are INTO helping!

[Hamie]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

LG don't use fault codes in conjunction with the standby LED,
If it goes permanently blue that's probably normal and is the TV "on"

In a darkened room is the panel "glowing" ?

[Gary_B]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Hello Hamie! Thank you for taking the time to help me out.

The screen does not give the slightest glimmer when I turn it on.

I know this is often a Y-sustain fault and that here is usually at least one fuse on the Y-sustain that I can check. It should read nearly no resistance even in circuit correct?

The sound it makes is bothering me though. I have not seen it described here before.

Gary.

[Hamie]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Are you able to read voltages?

[Gary_B]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Yes, I have considerable experience in electronics but none in modern TV's I have a DMM and good soldering tools and skills.

[Gary_B]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Hamie?

[Gary_B]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Hello Hamie! Thank you for taking the time to help me out.

After the usual delay it clicks normally but there is no picture and it makes a sound that starts out high pitched for about one second then drops an octave or two and continues like that forever. When behind the set it seems to come from the right top corner. When I play a file from the computer the sound seems normal except for the buzzing.

The screen does not glow at all when I turn it on.
The power supply and lights react normally to the remote.

I have considerable experience in electronics but none in modern TV's and I have a DMM.

What should I check first?

[Hamie]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Ok you want to check voltages.

VS and VA on the power supply.
Vsc and -vy on the y-sustain (board to the left of the power supply)
Z-bias (or VZB) located on the z-sustain (board to the right of the power supply)

Sometimes there are test points marked - and +
However sometimes they are measured ACCROSS a resistor that will be clearly marked.

They should match your panel sticker.

[Hamie]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

VS and VA are measured with the black probe to chassis ground.

[Hamie]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

[Gary_B]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Well..Thanks anyway Hamie,

I walked up to the TV to start to disassemble it and was shocked to see a HUGE CRACK running all the way from one side of the screen to the other!!

Obviously unrepairable.

What do you suppose happened? I did not see this crack before today. I suspect it somehow broke spontaneously and the crack developed due to vibrations (we live near train tracks).

Do LG plasma screens sometimes break (and lose vacuum/gasses) and then crack further WITHOUT being subjected to any trauma? I watched TV one night and the next morning it had the symptoms posted above and I did not see any crack. The crack was not noticed for weeks and the TV was unplugged and undisturbed the whole time??!?

I am stunned that the TV I paid over a thousand dollars for suddenly sustained what looks like traumatic damage when nothing physical happened to it at all!

Does this "just happen" sometimes?

[LGElectronics]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

Well..Thanks anyway Hamie,

I walked up to the TV to start to disassemble it and was shocked to see a HUGE CRACK running all the way from one side of the screen to the other!!

Obviously unrepairable.

What do you suppose happened? I did not see this crack before today. I suspect it somehow broke spontaneously and the crack developed due to vibrations (we live near train tracks).

Do LG plasma screens sometimes break (and lose vacuum/gasses) and then crack further WITHOUT being subjected to any trauma? I watched TV one night and the next morning it had the symptoms posted above and I did not see any crack. The crack was not noticed for weeks and the TV was unplugged and undisturbed the whole time??!?

I am stunned that the TV I paid over a thousand dollars for suddenly sustained what looks like traumatic damage when nothing physical happened to it at all!

Does this "just happen" sometimes?

Gary, the screen would not just crack like that. You might have had the smallest of cracks to begin with & as you know, Plasma TVs generate a lot of heat so over time that may have caused the crack to expand and depending on what the room temperature was on that night along with the TV cooling off may have just resulted in the crack expanding. The Neon and Xenon gases are in the sub pixels and unless you break those, they would not escape into the air, but then again, take into consideration how big those pixels are, the amount of gases that would be released are not that great if one or two sub pixels were to break. If you look closely at your screen, you may be able to see where that crack originated. You may have had that crack all this time. I used to work at a Best Buy and sometimes people would buy TVs at Christmas time as a gift and hide the TVs in the garage. When temperatures in the winter get very low and you move that TV into a room that is significantly warmer and turn it on or the temperature suddenly changes in the garage, that could crack the screen. Keep in mind that Plasma screens are glass or a glass substrate. LCD or LED LCDs use a type of plastic for their screens so are not as prone to the effects of temperature changes. That is why if people mentioned that they were purchasing TVs as an x-mas gift and they wanted to keep it in the garage, I would always advise them to let the TV sit before plugging it in and let it acclimatize to the room.^IV

[Gary_B]

Re: LG 50PQ10 normal lights and click remote ok no picture has sound buzzing upper ri

"Gary, the screen would not just crack like that."

It DID though! No temperature extremes, no impact.

One day working one day NOT, and a few days later it had a huge crack.

We live very close to railroad tracks and I believe that is what damaged my TV.