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Weird Screen color on Plasma

post #1 of 25
Thread Starter 
Hi everyone, I have a problem with my plasma screen which shows weird colors with lots of bright pixels spots, the best way I can describe it is taking a picture of it which I have a few.




Then at some point maybe a few hours of being like that, it then goes back to picture perfect, like all the colors in the right places and even brighter! Then again for a few hours it goes back to that:


Do you guys know if it's a circuit board problem or plasma screen pdp problem?

Model:
Legend PDP TV (the one from Bricks in Canada)
post #2 of 25
Thread Starter 
Anyone?
post #3 of 25
What is the make & model of your set?
post #4 of 25
Thread Starter 
Legend PDP TV
Model: LEP4218

I forgot to include that in the model (taken from the back of the TV)
post #5 of 25
Sounds like a circuit fault
post #6 of 25
I would agree, it's likely an internal fault. It is probably repariable, but the back cover will need to be removed to do some tests. It looks a lot like the panel voltages Vs, -Vy/-Vsc or Ve/Vzbias are set incorrectly.
post #7 of 25
Thread Starter 
if circuit, then video board or power board?
post #8 of 25
Y-sus, Z-sus, or power board.
post #9 of 25
Thread Starter 
How do i figure out what's right voltage?
here's a view of all the boards

Ysus


T-M B6298A4-C


782-PS4208-200C


Zsus
post #10 of 25
There is a sticker with "LG Electronics" PDP42V5012345 "Made in Korea" (or similar) written on it. On it are voltages such as Vs, Va and five unlabelled voltages usually Vset1 / -Vy / Vsc / Vset2 / Vzbias. Only some will be specified on most panels. Show us the sticker please.
post #11 of 25
Thread Starter 



post #12 of 25
You want to be looking at this sticker on the far right
http://cdn.avsforum.com/6/63/6331cc63_IMG_20130712_055915.jpeg

There will be points on the connectors going to the Y-SUS and Z-SUS marked VS and VA.

Those are the points to check.
post #13 of 25
Quote:
Originally Posted by Black-Macgyver View Post

Hi everyone, I have a problem with my plasma screen which shows weird colors with lots of bright pixels spots, the best way I can describe it is taking a picture of it which I have a few.




Then at some point maybe a few hours of being like that, it then goes back to picture perfect, like all the colors in the right places and even brighter! Then again for a few hours it goes back to that:


Do you guys know if it's a circuit board problem or plasma screen pdp problem?

Model:
Legend PDP TV (the one from Bricks in Canada)
Every television has some standard specification or rating according to locality. As you told that you are from Canada, If you give all specifications of your PDP TV model then I will definitely help you out of this trouble.
post #14 of 25
Thread Starter 
Quote:
Originally Posted by CHASLesley View Post

Every television has some standard specification or rating according to locality. As you told that you are from Canada, If you give all specifications of your PDP TV model then I will definitely help you out of this trouble.

Details of the tv based on that label on the back panel:
Legend PDP TV
Model: LEP4218
Manufactured for: Prima Electronis Inc.

Audio/Video Apparatus 62MB
Basic Model: PS-42T8

PDP Model: PDP42V70463
(By LG Electronics)
post #15 of 25
Thread Starter 
Quote:
Originally Posted by tom669 View Post

You want to be looking at this sticker on the far right
http://cdn.avsforum.com/6/63/6331cc63_IMG_20130712_055915.jpeg

There will be points on the connectors going to the Y-SUS and Z-SUS marked VS and VA.

Those are the points to check.

Where the white cables are on the top right of the Ysus board

From top to bottom
VS(1): 186.6 V
VS(2): 186.6 V
VS(3): 186.7 V

Where are red and blue cables midway on the left of the Zsus Board

From top to bottom
VS(1): 186.5 V
VS(2): 186.5 V
VA: 65.1 V
Edited by Black-Macgyver - 7/13/13 at 7:42am
post #16 of 25
Thread Starter 
According to that sticker it's not too far off, it's that a good thing?
post #17 of 25
The voltages are good. I would next try to reseat this cable: you should break the glue, remove it and plug it back in. Do the same for the other end. You can do this with the set plugged in to see if the picture improves when you touch or press it.

See this image for the connector: LEGEND.jpg 1802k .jpg file
post #18 of 25
Thread Starter 
No differences there when I touch it. I did unplug it and replug that cable you mention.
post #19 of 25
OK, see this manual:
http://www.toms-service-manuals.com/getfile.php?mode=viewpdf&req=LG_Plasma_Panels_42G1_42G2_42T1_42V7_42X2_42X2A_42X3A_42X4A_50G1_50G2_50H2_50H3_50R1_50T1_50X2_50X3_50X4_60H1_60H2_60H3_60R1_60X6_60X7_71H2_panel_alignments_%5BSM%5D.pdf.pdf&mfg=LG-Zenith

It has places for checking the -VY and VSC on your Y-SUS, and Vzbias on Z-SUS. You want to use the information for 42V7 panel. Check and see if those voltages are good.
post #20 of 25
Thread Starter 
That's a pretty awesome manual, but unfortunately, everything is in tack, right voltages based on the sticker for all that you asked me to check.
post #21 of 25
Thread Starter 
If it might help, I forgot to mention about the brightness of the TV when it is working right. Let say that picture I posted in the beginning of the thread, it would be much brighter and no green or other bright pixel dots would be visible and it would be a perfect image as well as brightness being bright. When displaying white background, It would be bright enough to keep the room lit up a bit. But right now it is not bright at all, it looks like a dimmed white (only when full screen). Also when it isn't full screen, it becomes brighter the smaller it is. So if I move my mouse from the computer screen to that TV, it is while and bright, but if I have the TV on a white background, it would be dimmed. So it seems the more colours it puts out, the less brightness it has and the darker the colours, the more brightness it has. Also the more colour it has too, it shows weird brighten pixels here and there as well, depending on the image shown. I hope this info helps out a bit to target what would cause it to do all this.
post #22 of 25
What you are describing is probably ABL and is common to most plasmas. The brightness of white is reduced as the usage of the screen increases to keep power consumption under a reasonable limit.

As for your problem, I personally think it is something with that cable or with the main video board or control board, but pinpointing the exact fault is difficult.
post #23 of 25
Thread Starter 
when you mean that cable, the cable you had me reset?
post #24 of 25
Yes. The main board and control board are connected by it.
post #25 of 25
Thread Starter 
After long overtime and dealing with company moving, I tried to play around with that board and still no change.


Not sure what board it is but it was connected to board above it which I moved to the side



Currently still showing

Goal image (and it did a few times on its own, but lately it hasn't shown the right image and seem to stay that way frown.gif )
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