Samsung 50" Plasma HPT5044, No Picture but powers up

[dmesser100]

Got this tv as a gift. have checked all the fuses, no bulged caps. so started checking voltages, im getting when its on 206v to the Y board, is that right? it has 5v next to the pin I checked. discounected the y board, still nada on the screen, no faint image either. so maybe the problem lies on the main board? im stumped

[mmartell]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

You should have used the Search function there is plenty about these models with exact symptoms. In the mean time I will tell you that you likely have at least one blown IC on the upper buffer board which may have in turn killed the YSUS. Is there a steady green light lit on the YSUS ?

[dmesser100]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

I have looked on that board closely, no burnt parts at all. and the led on that board is a steady green. Have searched it already, have checked the things mentioned in them. all seemed fine so far.

[mmartell]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

Have searched it already, have checked the things mentioned in them. all seemed fine so far.

Then you will know from your searching and checking of those things that a steady green light indicates a "Protection Fault" so your YSUS has a problem, possibly shorted mosfet(s). As for the buffer boards you need to pull them and use a meter to test for shorts. There is a link to the video in on of those relevant threads.

[dmesser100]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

well im learning more. it seems that the mosfet, q5500 and the 4 others on that heat sink are testing bad.

[mmartell]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

Alright now we're getting somewhere

It's very unlikely they are all bad but because they of the way they are wired if one is bad they will all appear that way. You need to get them out one at a time and test them. If you find a bad one check the others in circuit to see if they are still shorted or you have removed the short condition.

If you don't have the proper tools to remove the heatsink (requires alot of heat) you can remove the mosfets by removing the screw and lifting upward as there is just enough clearance under the heatsink. You may have to trim the leads a little under the board first and pull the mosfet forward as you pull it up but it can be done this way. Report back.

[dmesser100]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

Reporting back! I started removing the 88n30w mosfet one by one, testing what I took out and the remaining ones aon the board as I went. as fate would have it, it was the last one I removed out of the 4 that was bad. could not open and close it like I could the other 3. while im waiting on the replacement to get here, im going back everything else to double check if ive missed some thing else. thanks for the knowledge guys! I will report back when I get the new mosfet.

[tw2005]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

Reporting back! I started removing the 88n30w mosfet one by one, testing what I took out and the remaining ones aon the board as I went. as fate would have it, it was the last one I removed out of the 4 that was bad. could not open and close it like I could the other 3. while im waiting on the replacement to get here, im going back everything else to double check if ive missed some thing else. thanks for the knowledge guys! I will report back when I get the new mosfet.

Tom has done a video on testing the buffers but it's such a common fault should not be hard finding something with a search.

Can pretty much guarantee it will be shorted.

Getting a new FET is easy for the Ymain, finding a new upper buffer, that's the challenge. If you find a cheap source, let me know. We've got one at work that's had PSU,Y and buffer failure all at once!

[dmesser100]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

So when the main goes out it takes the buffer with it? that sucks. ive seen where others have had burnt components on theirs. mine shows none. but will look toms video

[dmesser100]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

So should replace all the mosfets that I took out? seems to be a fail waiting to happen

[mmartell]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

Depending on your skill level the buffer ic's can be replaced. But first watch the video and report back.

[dmesser100]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

Ok video was very helpful. seems two chips on my upper buffer board is bad. $61 repair service seems the best deal going so far.

[dmesser100]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

ZD5806 seems to be shorted and Q5000 and Q5002 I cant get any readings from, odd

[mmartell]

Re: Samsung 50" Plasma HPT5044, No Picture but powers up

Make sure there isn't a low ohm resistor around in parallel screwing up your readings.