LG50PC3D - help with image diagnosis.

[max007]

Hi Guys,

as per topic. This TV was in storage for a year or so. Initially the problem was it would turn on and then straight off. End result was a number of bad caps so l replaced the power supply and now this, so your thoughts appreciated see attached pic. Thanks in advance...

[grizzay]

Re: LG50PC3D - help with image diagnosis.

im having a similar issue with my tv as well, im going to keep an eye on this thread so i can figure out the problem

[max1636]

Re: LG50PC3D - help with image diagnosis.

To me the most likely cause of that is a faulty T-Con board which is what generates the image to go to the LCD Screen. I don't know if it's also common with LG TV's but a common issue with some Sony TV's were bad tabs on the LCD Panel. But I would say the most likely cause is the T-Con Board.

[tw2005]

Re: LG50PC3D - help with image diagnosis.

To me the most likely cause of that is a faulty T-Con board which is what generates the image to go to the LCD Screen. I don't know if it's also common with LG TV's but a common issue with some Sony TV's were bad tabs on the LCD Panel. But I would say the most likely cause is the T-Con Board.

It's 50" plasma, so no T-con or tab bond issue. Could be shorted Y buffer board/s.

Try disconnecting the lead from the ysus to the lower buffer and also the interconnecting cable between the bottom buffer and upper buffer boards.

Power up and see if top half goes good, if not try the reverse and disconnect the top, reconnect the bottom but leave the interconnecting cable disconnected and see if bottom goes good.

Sometimes you may spot one of the buffer ICs blown or have a small hole in it or on the buffer boards there are 3 SMD Fets which can go short.

The other common failure is the IPMs on both the Ysus and Zsus which are neither cheap or easy to replace but the fact the TV is on and the screen is bright most likely i'm thinking bad buffer boards.

[tom66]

Re: LG50PC3D - help with image diagnosis.

I would agree. Buffers.

[max007]

Re: LG50PC3D - help with image diagnosis.

Thanks for your guidance guys l will investigate and report back with the end result.

[max007]

Re: LG50PC3D - help with image diagnosis.

Ok tried tw2005 suggestions and results as follows:

when disconnecting the lead from the ysus to the lower buffer and also the interconnecting cable between the bottom buffer and upper buffer boards around one third of the screen goes black but has flickering green and red lines. When l do the same in reverse the picture stays almost identical to the original picture l posted. What can l try next? I can see no obvious damage to any of the buffer boards.

But just so I'm clear there is an upper and lower buffer board which run vertically on the same side as the ysus and also two lower buffer boards that run horizontally at the bottom of the screen. Is this correct?

cheers

[tw2005]

Re: LG50PC3D - help with image diagnosis.

Checked those SMD FETs on the buffers for short cct? Any shorts between earth and at the ribbon connetcors on the buffer boards?

maybe that procedure does not work on these, does on the 42" SD models.

Not a model I enjoyed fixing but all 3 I fixed were failed IPMs and nil display, and in protection mode.