LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

[tom66]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Nice! Interesting to hear it's such a common issue as I've seen a few others on here with the same fault.

[shrmn]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Hi, I signed up on this forum to thank you guys for detailing all the technical instructions to getting this LG TV to work again!

I had the exact same issue of the image distorting and inverting and initially thought the unit was a goner (it's coming to 5 years old). While it was under warranty coverage, I've had the "picture board" and "motherboard" changed once each already (on two different occasions) and since then it was working fine until about two weeks ago where those issues started coming out.

I skipped the whole thing about testing patterns and whether it was the lower center board because I was pretty sure the main board (upon which the input connectors are placed) was the one at fault - my HDMI inputs 1 to 3 suddenly stopped working earlier this year and I had to move my only input, an A/V Receiver (Onkyo TX-NR709) on to HDMI 4.

Called LG customer service and they had a direct menu option on the automated telephone machine to get to the "spare parts" department (Press 1 for English then 2 for Spare Parts).

The technician on the other end of the line was extremely quick and detailed on the terms of purchasing the spare part and identifying which part I needed (I told him the model number of the TV and then said the board where inputs were placed on). He gave me a model number which I could not identify on my board so he said to bring along the board to do a comparison over at the spare parts counter at 991D Alexandra Rd (its the location of the old ITE Pasir Panjang, ample parking space available).

I did exactly that (they only replace just the board - unscrew the plastic housing for the side ports) and noticed the difference in the model number at the bottom of the board.
My old board: EAX61744402(4)
The new board: EAX61744403(1)

I accepted it anyway seeing that the locations of the ports and mounting points were the same. Total cost was SGD$105.00 before tax.

Brought it home, fixed it up and voilà! It worked! It did ask me to select a region for which I only had two choices - Australia or New Zealand, as the OP mentioned. I selected Australia -> WA (Western Australia). Then proceeded to test HDMI and the antenna cable inputs. Auto tuning. Worked - found 12 analog TV channels, 0 DTV and radio channels.

Ultimately it was fixed thanks to you guys! just wished I found this thread before purchasing a new TV...

[tingshen]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Sandtang!!!!!!

I can't imagine I manage to find you here through my very first original created thread at hardwarezone forums!!! Gave you my number too!

And seems like I am the 3rd person from Singapore having logic board problem on the same LG TV!!

I bought the logic board about 15m ago and replaced it because my HDMI was not working suddenly. Refusing to pay SGD 214 for consultation, the technician was kind enough to "guess" it is the logic board problem over the phone. Being only a computer science graduate, I got no clue how to replace the board of such a heavy TV. Nevertheless, I just replace based on the way I fix computer servers lol. It was back to life and now my TV has no picture but only sound. Since you have most of the components (I checked shopjimmy and it seems like it has nothing for PK950!!!), I can conveniently get from you if its not the logic board problem.

Now I shall replace with my very first board and see if I can get picture, if not it is not the logic board, and what shall I do?

I will try the test pattern method too, now the problem is, where to find a jumper for it?

[tingshen]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Sandtang, I noticed you dismantle the stand and let it lie on the floor. How did you do that ?

This 50" plasma is damn heavy! I manage to fix everything by just removing the back cover and with it standing still lol

[tingshen]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Hi guys, I tried the jumper test pattern and my screen is still blank out, I was using the Cat 5e wire to short R51 & R52, not sure if it is sufficient. Where can I buy a proper jumper to do so?

Changing to my old logic board can't seem to make it work either, the previous logic board just couldn't accept any HDMI input but we can see something on screen.

Please advise

[tom66]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

A bent paperclip or small piece of wire works fine. It is important to also disconnect the LVDS cable or the test patterns will not show.

[tingshen]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Thanks Tom. I will try paper clip again.... The LVDS cable refers to the cable to logic board right ?

[tom66]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

It is the cable between the main board (which has the HDMI ports on it) and the control/logic board (which has the test pattern jumper.) The LVDS cable carries the video data between the two boards.

[tingshen]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Thanks Tom!

I have used a paper clip to jumper the two tiny holes and disconnect LVDS cables to the mainboard.

Screen is still blank.

I took a video and the logic board has the LED D1 flashing after every few seconds. I guess that's the test pattern signal.

Could it be my plasma screen is gone ?

View My Video

[tingshen]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Hi guys, what shall I do next ? Few days without TV

I am about to ask a technician down for an initial inspection. That would cost about USD30 for him to tell me what went wrong.....

[tom66]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

In a dark room do you see a slight glow from the screen when it is turned on?

[sandtang]

Re: LG 50PK950-TA shaking/flipping image (replaced 5 boards still the same)

Hello tingshen, I subscribe to this thread but not sure why it hadn't sent me update emails when you posted. I also havent visited hardwarezone for a while and just logged in today. Sorry about that. Glad you found Tom though. How is it so far? Maybe you want to respond to Tom's query or share what you've done since.


Hey Tom