lg 50pa4500 picture very bad

[tonytiger]

hi guys,

this is a tv that im working on the first time it arrive the zmain board was bad and the upper buffer board...so i replace them with new one....

now i have the picture and everything working but the picture is so bad that there are missing colors,ect....picture included.

did anyone ever had these problem after replacing the board.

all reban seem ok an the both side.

any help will be appreciated.thank you.

[dick_barton]

Re: lg 50pa4500 picture very bad

Run the self test and see if your colours are OK

[tonytiger]

Re: lg 50pa4500 picture very bad

his the self test the one that need a jumper around r452 and 451.i did forgot about this test...not sur is that is correct test.

[dick_barton]

Re: lg 50pa4500 picture very bad

That is part of it. Do a search for "self test" because I think you have to remove the ribbon from the power supply to the control board.

[dick_barton]

Re: lg 50pa4500 picture very bad

Duplicated previous post - ignore

[tonytiger]

Re: lg 50pa4500 picture very bad

well i did the test and all colors are there but still ugly.could a main board do this even if there is picture and sound or most likely another problem...thanks for your help

[dick_barton]

Re: lg 50pa4500 picture very bad

If you ran the self test and it passes then it normally suggests a mainboard problem. However in your case the mainboard does not appear to be the problem.

I'm not a plasma expert but it may be your control board at fault.

Perhaps more experienced people can offer you better advice.

[tonytiger]

Re: lg 50pa4500 picture very bad

that the problem,i did change the control board also,i just forgot to say it....but me also am not a plasma expert..but thanks you for the time and help..very appreciated.

[dick_barton]

Re: lg 50pa4500 picture very bad

On the plasma panel at the back of the set there is a label with voltages given. Have you then checked that all the voltages on the circuit boards match the label?

[tonytiger]

Re: lg 50pa4500 picture very bad

yes all voltage are the same.have no more ideal what to check....

[maxvalutech]

Re: lg 50pa4500 picture very bad

Have you done a factory reset via menu?

[ReeceyBurger123]

Re: lg 50pa4500 picture very bad

Zsus erc coils, resolder them. Or could be two resistors on Ydrive for Yfr that are failed.

[dskall]

Re: lg 50pa4500 picture very bad

Don't know a lot about plasma but you may have to go into service menu and change some settings. Put your old control board back in and see if that changes things.

[Davi.p]

Re: lg 50pa4500 picture very bad

I don't know about plasmas, but once i have followed a Samsung plasma thread, that has a tipical solarization defect, it was the main board, it seems to me that in plasmas gamma correction is made on main board.. possible? tell us the mainb. model code..

[tonytiger]

Re: lg 50pa4500 picture very bad

thanks for the time...i did change the upper buffer board,zmain board and the logic board.i did swape back the old one 1 by 1 to see if there was a defference but no always the same...i did a factory reset no change,now im trying to find if there is a firmware updates,ect...but the one i found did not work...so still checking.but at my experience i do think that Davi.p is right by saying the main board since that is where i supect the problem....but customer will not pay $200 for this board...so i guest it will be take apart for recycling by the weekend....thank you.

[dick_barton]

Re: lg 50pa4500 picture very bad

But how could it be the mainboard. If you ran the self test with the mainboard disconnected and the colour patterns displayed are all still wrong then that does not point to the mainboard?

[Davi.p]

Re: lg 50pa4500 picture very bad

ok dick you're right... from the pictures it seems that images lack of many bits of colour information, maybe some flat cables problem...?

[tonytiger]

Re: lg 50pa4500 picture very bad

yes i dit check all these flat cables,i re-seated them more than once try to find if they where going forther in ect,but all seem to be ok,i will try and experience today by heating the main board probebly will not do any changes but no much more to try....

[Davi.p]

Re: lg 50pa4500 picture very bad

i'm not sure about your post #6, the self test is positive or not? If not, no reason to suspect mainboard...

[rccrasher65]

Re: lg 50pa4500 picture very bad

yes i dit check all these flat cables,i re-seated them more than once try to find if they where going forther in ect,but all seem to be ok,i will try and experience today by heating the main board probebly will not do any changes but no much more to try....

Do as Reecy suggests on post 12. Your problem is not the main board. Take the advice of the professionals, thats why we are here!