Samsung FP-5084 plasma tv no picture

[freakaftr8]

Ok guys im stumped. This TV powers on to a grey screen (sustain boards are working). Waiting for the info banner to come up. Nothing but a dark grey screen. So I figured mainboard or logic board. I went ahead and crossed pin 1 and 2 on logic board and removed LVDS cable and bingo color patterns..

So I looked over mainboard and nothing wrong with it as far as testing goes, but I figured what the heck ill pick one up anyway. New board came in off ebay guaranteed working..

Installed, and same issue... So I have never encountered this yet, but is there a chance the logic board can be faulty even though I can get color patterns up? LVDS cable looks good and as far as I can tell no problems with it.

[ajshoe]

Re: Samsung FP-5084 plasma tv no picture

how about a pic of insides ?? try reversing LVDS cable ??

[freakaftr8]

Re: Samsung FP-5084 plasma tv no picture

Tried reversing the cable no change. Pics to come soon

[ajshoe]

Re: Samsung FP-5084 plasma tv no picture

think the model # is Samsung FP-T5084 ? also assuming u tried selecting inputs ?

[freakaftr8]

Re: Samsung FP-5084 plasma tv no picture

Yes it is. Sorry. It's actually FP-T5084X/XAA. Yep inputs have no change. menu shows nothing

[freakaftr8]

Re: Samsung FP-5084 plasma tv no picture

Well a new logic board fixed this set. Somehow oddly even though I could engage the test patterns off the original logic board it would still not display anything coming from mainboard.
But has a beautiful picture now...

But now a new issue..
With scene changes and a picture pulling more current from the power supply the power supply makes noise, almost a buzzing sound. Probably from a transformer? its sporadic.

[tom66]

Re: Samsung FP-5084 plasma tv no picture

It's possible for the LVDS input of the control board to fail. Rare, but possible. To be certain you can use a scope and check the LVDS data lines.

That kind of buzzing is pretty typical for older plasmas and should not be heard once the case of the TV is on.

[freakaftr8]

Re: Samsung FP-5084 plasma tv no picture

True I'm familiar with the frequency sounds coming off the sustains on plasmas. This is certainly power supply. And man does the power supply get hot. Hotter than most plasmas I've encountered.

[freakaftr8]

Re: Samsung FP-5084 plasma tv no picture

http://s845.photobucket.com/user/inf...02d2d.mp4.html

Here's the sound. Loud and gets louder while it's been on for a while. Lots of heat coming from the power supply. Hotter than normal.

[freakaftr8]

Re: Samsung FP-5084 plasma tv no picture

Checked for cold solder joints. None found. It's definitely one of the primary transformers. The biggest one on the power supply

[tom66]

Re: Samsung FP-5084 plasma tv no picture

It sounds just like what my Panasonic plasmas do. The transformers on the power board do buzz a lot. It draws about 500W from the mains so that's not at all unexpected.