Samsung PN42C430 Plasma no picture please HELP

[sergio2013]

My Plasma has an issue that im having a hard time diagnosing. Sometimes the TV will stay on for many hours with no problems other times it will stay on for a short while then the screen will just go black no light at all, but the sound keeps working, if I turn off the TV from the remote and back on again the picture comes back sometimes for a short while and sometimes for many hours, when it happens again I just have to turn it off on the remote and back on again in order to get the picture back.

I have checked the VA and VS Voltage when the TV is operating correctly and its at spec, I also measured the VA and VS voltage when the TV experience the issue and its very low to almost nothing. All the capacitors on all the boards look ok with no bulges. Anyone know what could be the fault?

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

I would try heating up boards one at a time and seeing if you can get the fault to occur again -- then you will know where the problem is. As it's almost certainly heat related. A hairdryer or hot air gun works -- keep heat below 60°C.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

I would try heating up boards one at a time and seeing if you can get the fault to occur again -- then you will know where the problem is. As it's almost certainly heat related. A hairdryer or hot air gun works -- keep heat below 60°C.

I don't think it would be heat because I don't need to leave it off to cool down, I just turn it off and right back on again and it comes on and sometimes stays on for many hours, so it doesn't need a cool down period, also I have been watching it in a cool basement with the back off and it still does it, so I don't think that's what it is. Any other ideas?

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

Almost always it is heat when a set will work for some time then shut off. The reason I say this is that when the power supply turns off (goes into standby) it can cool down quickly. A cracked solder joint or intermittent component can be operating right on the boundary of the working and not meaning the slightest change is all that is necessary. There are a few exceptions but it's a generally good idea to try a heat test first.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

Almost always it is heat when a set will work for some time then shut off. The reason I say this is that when the power supply turns off (goes into standby) it can cool down quickly. A cracked solder joint or intermittent component can be operating right on the boundary of the working and not meaning the slightest change is all that is necessary. There are a few exceptions but it's a generally good idea to try a heat test first.

Maybe your miss understanding, it does not turn off, the screen turns off, but the TV continues running and has power and sound, it does not shut down. But if you say that it could be heat then ill try that test.

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

The plasma display power supply is mostly separate from the main board (sound, processing) power supply. The plasma display part has to provide around 200W peak.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

The plasma display power supply is mostly separate from the main board (sound, processing) power supply. The plasma display part has to provide around 200W peak.

Well I did as you said and its for sure not heat related I heated up each board one at a time while the set was running, I gave it enough heat that I could not even leave my finger on the heatsinks and it kept running with out any problems not even an artifact on the screen because I put a mirror so I can watch it as I do it. So now what?

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

OK, in which case we need to check some other things.
Let's try and rule out the main board by activating the control board self test.
https://www.badcaps.net/forum/showpo...61&postcount=2

Leave the patterns running for the normal time the TV takes to cut out. If the TV does not cut out, then the problem is most likely on the main board. However, I would consider that possibility unlikely.

It should look like this:
http://www.youtube.com/watch?v=JCtF5...ature=youtu.be

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

OK, in which case we need to check some other things.
Let's try and rule out the main board by activating the control board self test.
https://www.badcaps.net/forum/showpo...61&postcount=2

Leave the patterns running for the normal time the TV takes to cut out. If the TV does not cut out, then the problem is most likely on the main board. However, I would consider that possibility unlikely.

It should look like this:
http://www.youtube.com/watch?v=JCtF5...ature=youtu.be

Ok sounds good im doing that now and its showing a bunch of solid colors and there is scrolling patterns like its supposed to have, so ill leave this running and ill report my findings if it turns off today and if it keeps going ill report tomorrow, thanks so far for your kind help.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

Oh forgot to say that last night I did do a similar test from the TV's menu and left it overnight and when I woke up it just had sound, but no picture and had to turn it off and back on again to get picture back. I don't know if its basically the same test as this, but it was similar patterns for removing screen burn in.

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

But in that case were you feeding it signals in via a computer or similar device through the main (video input) board?

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

It had a signal from a satellite receiver going into HDMI port number 1 at the same time I ran that test. so I could hear the TV sound, but it didn't display the TV picture, just the patterns over the sound.

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

But anyway, you can't remove screen burn from a plasma display by using patterns. You can reduce image retention but that usually doesn't happen on Samsung plasma displays. If it was executed from the main board, the main board was probably generating the patterns and we want to check the control board.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

Ok no problem I will leave this test running. Also a bit more info on the issue, I'm assuming it could be related to this problem, but sometimes not all the time the picture flickers slightly, like fluttering and one time when I turned it off and back on after the screen went dark it came back on with tons of red dots all over the place the whole screen was distorted and I just left it on and slowly from top to bottom the dots started disappearing till the picture was perfect again, that happened only the one time.

[Alastair E]

Re: Samsung PN42C430 Plasma no picture please HELP

Have you tried tapping the crap out of each and every board --carefully, with a plastic handle of a screwdriver......?

This often will show up dry-joints/bad connections on PCB's...

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

That would be my suggestion if the control board test makes the TV shut down -- at the moment I would like to see if the main board is faulty as it is more common with these newer Samsung TVs.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

Ok ill report my findings, thank you and this is a great site.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

Ok the screen just turned off so it took an hour and a half. What do you suggest for the next step? TV is still on but screen is black.

[tom66]

Re: Samsung PN42C430 Plasma no picture please HELP

The cable that goes between the control board and power board -- check the pins marked VSON, PSON and the 5.2V/5.3V/5.4V/15V if present.

[sergio2013]

Re: Samsung PN42C430 Plasma no picture please HELP

The cable that goes between the control board and power board -- check the pins marked VSON and PSON.

What do you mean check them? with my multimeter? with the tv on or off? with the problem or turn it off and back on so it has no problem then test?