Lg 50ps3000

[sparks2112]

Got an lg50ps3000. When i turn it on light goes blue as if ok to go. But no pic or sound. When i unplug ysus board get sound but no pic. If i plug that back in and unplug zsus board i get picture and sound (colour not right, but good pic) simple question. Y sus failure or z sus failure. Or both? Or something else lol.any help is much appreciated. Thanks

[jasonr2000]

Re: Lg 50ps3000

Can you post some pictures please of the issue and the whole back side of the tv showing all the boards

[steviewonder]

Re: Lg 50ps3000

definitely Z sus failure,no doubt at all on that description.

[sparks2112]

Re: Lg 50ps3000

no pic or sound or back light when i start tv. Only when i unplug one of the boards.

[sparks2112]

Re: Lg 50ps3000

Thank you. Could i repair this with them kits you get on ebay or amazon. May have to dig a little deeper to troubleshoot this one. Get back to you if sort it. Thanks again for your time and knowledge

[steviewonder]

Re: Lg 50ps3000

yes,there are no backlights-it's a plasma.with the zsus unplugged,you usually get a dark,red orientated picture...It will have a short circuit when connected causing the psu to trip!

[steviewonder]

Re: Lg 50ps3000

Luckily,z sus panels are rather cheap on ebay,so you should be up and running in no time.Beware of repair kits-they don't always cover everything that can fail,and need considerable skill and knowledge,quite often,to fit,if not experienced with this kind of thing..yes,let us know how it goes!

[sparks2112]

Re: Lg 50ps3000

Ye im a noob. but not shy to have a go. Just looked a board up on ebay £17 so try that option. Cheers

[sparks2112]

Re: Lg 50ps3000

finally got board this morning. fitted and working and sold! .thank you very much stevie.

[candy-men]

Re: Lg 50ps3000

Hi Folks, i´ve bought a 50PS3000 as defect for repair for myself. The reason why it doesn´t show any picture was found very fast: The ZSUS Board was faulty. I´ve then found 3 Mosfets on this board , and all are fryed. So i replaced the two 20NF20 , the one 51N25 and a fryed 45F122 against a IRG4BC40F which seems compatible. Now the TV is working again, and everything seems to be fine. But i think the little Heat-sink, on which the both 20NF20 are mounted, is far too hot!!! It is nearly 50°C , and i think this is too much for this one. What could it be? If i let it this working in this way, i believe the 20nf20 will be fryed soon again...
Or is it normal that this is the hottest heat sink on the PCB?

[ReeceyBurger123]

Re: Lg 50ps3000

Have you added enough thermal paste ? Also did you replace the resistors for the fets they normally fail O/C and can cause issues ?

[candy-men]

Re: Lg 50ps3000

You mean the both 2,2R Resistors? They are okey. Or do you mean the both 470R Resistors for the Gate? But these ones are also okey
Thermal Paste is added, i had to insulate the Fets with a silicon pad, beause they are normal To220

[candy-men]

Re: Lg 50ps3000

But if they dont have a good thermal coupling, the heat sink would not be that hot!!! So the heat coupling is definitly okey ;-)

[ReeceyBurger123]

Re: Lg 50ps3000

Yeah its a bad design overall, its the reason why they commonly fail is because Lg never engineered them with good cooling so they get very hot and slowly break down until the point where the fets blow and short at start up. Maybe add a fan to the heatsink ?

I also covered this theory about them fets failing in one of my videos.

[candy-men]

Re: Lg 50ps3000

If it is normal thta the little heat sink is that warm, i can live with it. But i think this would not be good. Adding a little Fan is possible, but this would make a little noise. I only need to know if it is normal and the ZSUS Board is working in its parameter. I will measure the Temperatur an give you some values.....

[ReeceyBurger123]

Re: Lg 50ps3000

Run it for a good few days with the cover slightly screwed on see if it fails.

[candy-men]

Re: Lg 50ps3000

Now i've discovered a strange behaviour. The Temperature raises fast after booting up the TV. In the first Two Minutes the HeatSink is up to 120℃ . But then the Temperature falls back to 55℃ and stay there while working in normal Operation.

[ReeceyBurger123]

Re: Lg 50ps3000

Thats because on start up the Panel needs to be primed properly so you dont get M/D. So the controller sets the Sustain boards to work slightly harder to get the gases up to operating temperature faster so you dont get any misfires/sparkles in the image. But when the gases are hotter they need less power to go to them to emit light.