PS43D450A2WXXU picture quality problem

[predseda]

Hi Guys,

I recently repaired my PS43D450A2WXXU where I suspected that the Y-Main is faulty. Just to make sure I also ordered X-Main. After I replaced the Y-Main TV started to work however when I was watching the TV I have noticed this shivering redish/greenish maps showing up on the screen from time to time. It is especially noticable when the picture is purely white. As it is mainly happening on the side of the screen where there is X-Main I tried to replaced it as I had a spare part for it, but it didn't help. Any idea what can be wrong? Is it the display or do I need to replace also power supply or signal board?

Thanks.

[tom66]

Re: PS43D450A2WXXU picture quality problem

I have replied to your post in another thread, but I will repeat:

Try checking the PSU Vs voltage matches the panel specification. Samsung have a technical bulletin out about increasing the Vs voltage from the panel spec of 207V to 212V for pink diffusion on full white images.

[predseda]

Re: PS43D450A2WXXU picture quality problem

Hi Tom,

Thanks for reply.

I'll try that this evening, can't wait

Thanks again.

[predseda]

Re: PS43D450A2WXXU picture quality problem

Hi Tom,

I have tried to adjust the Vs and have to admit that the pink diffusion is now occurring less frequent and is less visible. I have gone to 213 V but was afraid to go further. Is there any safe upper limit of Vs to try?

Thanks.

[tom66]

Re: PS43D450A2WXXU picture quality problem

An absolute safe limit would be around 218V.
You can also yet checking the -Vsc voltage is OK.

[predseda]

Re: PS43D450A2WXXU picture quality problem

it measures -183 V, sticker says it should be -185. I am playing with this voltage now.

[predseda]

Re: PS43D450A2WXXU picture quality problem

I am sticking with Vs=213 V and Vsc=-185 V. It is not fully gone but the area which has diffusion is only in the middle on the left side of the screen(before it was happening through the whole horizontal middle of the screen). And the diffusion is not as intense and frequent as it was before. It is only happening when the picture has big area of white or light blue on left side.
I have tried Vs=215 V but didn't see any difference. Also tried Vsc= -175 V but again no difference from -185V.
I have tired Vsc=-189 and felt it was little less obvious but still visibly there. What would be safe ranges for Vsc?
It is not ideal but it is acceptable for now.

Thanks for good tips Tom.

[tom66]

Re: PS43D450A2WXXU picture quality problem

-Vsc must not go below -200V. i.e. -210V is too high. Also, please note you should not try adjusting Va as doing so can cause irreparable damage to the plasma panel.

In addition, make sure you've installed latest Samsung firmware update -- if only to prevent repeat failure of X- or Y-main boards.