Samsung Ps-50q7hd plasma tv, green dots??

[leeno382]

Hi Guys and girls, i am new to this forum, and thought id see if anyone is able to help me out, I have recently been given a 50" plasma the samsung ps-50q7hd and my mate who give me it told me it had this fault with it, that i thought wouldnt be anything major to fix, (I am a pc engineer) and fancied my chances, it turns on great operates as normal, but the its got loads of green dots over about 3/4 of the screen, i come across a site that the guy said alter the vscan to adjust the image which i did, and the picture immediately went 50% better, but there still there? does anyone have a rough idea what i could try, i think i am going to have to replace a board or two, but the parts are easily available? am a newb to tv's as such and i would appreciate your much needed info....

This is very similar to what ive got:

http://www.youtube.com/watch?v=vFyd7irtF7U

Thank you

[tom66]

Re: Samsung Ps-50q7hd plasma tv, green dots??

"Sparklies" are caused by the plasma driver Y-sustain/Z-sustain not completely erasing previous pixels (wall charge on the pixels.) It is caused by the panel aging, but it is often fixable.

Adjusting Vscan sometimes fixes it, but the timing controls Yfr and Yrr can help too. I found Yrr to fix the problem on the one Samsung plasma I have repaired. Adjust it one way a small amount while getting a friend to look at it (or use a mirror). If the picture gets worse, adjust it the other way. (Good idea to make a mark of the adjustment beforehand.) If it gets better, but it's still got the sparklies, you can drop Vs by about 5-10V. The picture will dim by maybe 5% (barely noticeable), but it significantly reduces sparklies in my experience. Also check the voltages with a multimeter if possible.

[leeno382]

Re: Samsung Ps-50q7hd plasma tv, green dots??

"Sparklies" are caused by the plasma driver Y-sustain/Z-sustain not completely erasing previous pixels (wall charge on the pixels.) It is caused by the panel aging, but it is often fixable.

Adjusting Vscan sometimes fixes it, but the timing controls Yfr and Yrr can help too. I found Yrr to fix the problem on the one Samsung plasma I have repaired. Adjust it one way a small amount while getting a friend to look at it (or use a mirror). If the picture gets worse, adjust it the other way. (Good idea to make a mark of the adjustment beforehand.) If it gets better, but it's still got the sparklies, you can drop Vs by about 5-10V. The picture will dim by maybe 5% (barely noticeable), but it significantly reduces sparklies in my experience. Also check the voltages with a multimeter if possible.

Thanks Tom, i will have a go at that now, providing i can find my multimeter, is there any point in changing any boards then? i was going to change the small power board that the vscan is on, but i might not need to now eh? thanks regards Lee

[tom66]

Re: Samsung Ps-50q7hd plasma tv, green dots??

Thanks Tom, i will have a go at that now, providing i can find my multimeter, is there any point in changing any boards then? i was going to change the small power board that the vscan is on, but i might not need to now eh? thanks regards Lee

No need. Sparklies aren't caused by faulty boards, except on LG's, and that is a control board issue (firmware out of date.)

[leeno382]

Re: Samsung Ps-50q7hd plasma tv, green dots??

No need. Sparklies aren't caused by faulty boards, except on LG's, and that is a control board issue (firmware out of date.)

excellent mate, i appreciate you taking the time to help me out on this, i have made a small adjustment to the bits you mentioned, exept the vs and they do make a small difference, however the screen is still 3/4 with green dots and the the other 1/4 is black ? any ideas?

[tom66]

Re: Samsung Ps-50q7hd plasma tv, green dots??

excellent mate, i appreciate you taking the time to help me out on this, i have made a small adjustment to the bits you mentioned, exept the vs and they do make a small difference, however the screen is still 3/4 with green dots and the the other 1/4 is black ? any ideas?

Could be bad buffers... but did you try Yfr too?