Samsung Ps-50Q96HDX/XEU

[ReeceyBurger123]

Hello we need help with this samsung Ps-50Q96HDX/XEU as this plasma has 3 of us tv techs at our knees, the ysus was repiared by replacing the whole row of power mosfets, there we two blown mosfets that had als blown their resistors replced them with good exact parts. The tv will now work I see that the xsus has lit its back row of pixels but the ysus isnt lighting its from row and nothings workson thelowwer half of the screen, checked the ysus over and over and cant find nothing out of spec, the ysus is a LJ41-50120A can anyone who has repaired one of tese before give us an insight into what to check next, any help is much appreciated thank you.

[tom66]

Re: Samsung Ps-50Q96HDX/XEU

Hard to tell what you're referring to... bottom half missing or the interlaced lines? The lines appear to be the pixel drive lines and are normal.

BTW, X-main and Y-main both drive the -whole- screen, both X-main and Y-main appear to be working, likely it's a Y-buffer fault (check cable between buffers seated properly)

[satinser]

Re: Samsung Ps-50Q96HDX/XEU

From the picture most likely the bottom connector from ysus board to buffer board either not seated properly or not at all.

[ReeceyBurger123]

Re: Samsung Ps-50Q96HDX/XEU

Thanks for the reply we are going to try new buffers and double checking the ysus for anymore shorts. Will get back to you on how it goes.

[ReeceyBurger123]

Re: Samsung Ps-50Q96HDX/XEU

Tried different buffers and still half a screen so that leads us to think that the ysus is still faulty. As this model of ysus seems to have a lot of issues will caps going bad then wiping out the power fets and small smd parts, we are going to try replacing the old ysus or repair it.

[tom66]

Re: Samsung Ps-50Q96HDX/XEU

I really doubt the Y-sus/Y-main is causing this fault as you have an otherwise good image on the working half. There is a small chance the data isolator which carries the data from Y-sus/Y-main to the Y-bfufer is bad but I would say that is pretty rare.

[ReeceyBurger123]

Re: Samsung Ps-50Q96HDX/XEU

I really doubt the Y-sus/Y-main is causing this fault as you have an otherwise good image on the working half. There is a small chance the data isolator which carries the data from Y-sus/Y-main to the Y-bfufer is bad but I would say that is pretty rare.

We had to repair the ysus before hand, replaced the fets and some smaller parts so we aren't sure weather or not its working. We have also tried different buffers that were good I will take photos of the ysus and buffers in the morning thanks.

[freakaftr8]

Re: Samsung Ps-50Q96HDX/XEU

Do you mean that you can see the bottom of the screen backlighting but nothing being displayed? If so your buffers are working correctly but data is not being transmitted to the lower buffer.

I am currently working on one of these boards here in the States. HP-T5054 model. I have never run into a board with more problems than this. Mosfets test ok but they keep blowing and at one point I had lost the lower half of the screen myself. unfortunately to repair this board I have to replace the whole bank of MOSFETs again and I gave up in put it on the back burner until I can find another board. Let me look at that bored again tonight I believe there is a SMD IC on each side that controls the data going to the buffers.

[ReeceyBurger123]

Re: Samsung Ps-50Q96HDX/XEU

Do you mean that you can see the bottom of the screen backlighting but nothing being displayed? If so your buffers are working correctly but data is not being transmitted to the lower buffer.

I am currently working on one of these boards here in the States. HP-T5054 model. I have never run into a board with more problems than this. Mosfets test ok but they keep blowing and at one point I had lost the lower half of the screen myself. unfortunately to repair this board I have to replace the whole bank of MOSFETs again and I gave up in put it on the back burner until I can find another board. Let me look at that bored again tonight I believe there is a SMD IC on each side that controls the data going to the buffers.

Yes thats what is happening the pixels ignite but nothing gets displayed, all the fets test good though. I will check it in the morning as that board is at my mates thank you.

[freakaftr8]

Re: Samsung Ps-50Q96HDX/XEU

Have you checked the ribbon going from the control board to the YSUS? Also make sure it's seated properly. on this model the control board is completely covered up by the main board and its a pain in the arse to get to unless you remove the main board and bracket and I have made the mistake in the past of pulling out the ribbon from the control board causing all sorts of symptoms when it was just something simple. Also I have seen ribbons with micro fractures causing data loss.

[ReeceyBurger123]

Re: Samsung Ps-50Q96HDX/XEU

Have you checked the ribbon going from the control board to the YSUS? Also make sure it's seated properly. on this model the control board is completely covered up by the main board and its a pain in the arse to get to unless you remove the main board and bracket and I have made the mistake in the past of pulling out the ribbon from the control board causing all sorts of symptoms when it was just something simple. Also I have seen ribbons with micro fractures causing data loss.

Will have a good luck tomorow I think it was all in fine but now you say that im not sure, I will update you tomorrow thank you.

[ReeceyBurger123]

Re: Samsung Ps-50Q96HDX/XEU

Just sorted this tv months after turns out there was a shorted ceramic capacitor and zenerdiode behind the lowwer heatsink with the fets with the fets mounted on replaced that and lower half of screen come back