Samsung PS50C550 screen not powering

[stupot1]

Hi, this is my first post.

I have a Samsung PS50C550 plasma with a smashed screen (don't ask), after the screen got smashed the TV would make a 1(ish) second buzz then turn off.

I found another Samsung PS50C550 on eBay that had a good screen but apparently had "just stopped turning on".

I have moved the good electronics over but the TV will not turn on, after this I started googling and looking for a service manual but to no avail.

These are my findings though:

With all the boards plugged in I get 6 flashes from the power LED after turn on.

With all the boards plugged in, the Va and Vs voltages are not held up to there 210 and 65 volts, the PS_ON signal from the LOGIC board is held low so i'm guessing this is turning these voltages off.

When I unplug the Y_SUS board from the LOGIC board, PS_ON is 3.3V and the Va and Vs voltages are good - also the power LED on the front panel behaves as normal, ON when in standby and OFF when TV is turned ON.

This behaviour with unplugging the Y-SUS board is the same with both sets of Y-SUS and Y-Buffer boards.

Does this indicate that there could be a problem with the new panel or possibly both sets of Y-SUS boards?

I have also had a play around shorting out the jumpers on the LOGIC board with all the boards plugged in, to try and get the test screens to display. And I am sure I got the screen to flash up for about 0.5s with a display but have been unable to repeat this so think this could be a frustration induced hallucination!

Additionally, does anyone know what the different LED flashing pattern are on the LOGIC board? The two green LEDs LED2000 and LED2001 - shown in image.

With the Y-SUS unplugged, which I am presuming is running OK and not detecting a fault, is LED2000 flashing at approximately 1Hz.

With the Y-SUS plugged in, which I guess is a fault detected safe mode, LED 2001 flashes much slower - maybe 0.25Hz.

Thanks for reading and any help or input would be greatly appreciated.

I do electronics work for my job so have access to meters, scopes etc and also a technician who will be happy to undertake any surface mount rework for me (after some beer bribery).

Stuart.

[ViperRunner]

Re: Samsung PS50C550 screen not powering

Hey!

Sorry for posting on your topic stupot1, but i am unable to open threads, and how it's issues that look alike, i though you wouldn't mind for me to post here.

I have a
SAMSUNG Plasma
Model: PS50C550G1W
Model Code: PS50C550G1WXXC
Version: IZ02
Manufactured in January of 2011

I was working fine, until a couple of months ago it turned off, and when on and of with a clicking noise, and didn't answer the remote. When it was on, the screen was a dark grey that could hardly be seen.

Well, for what i read on the symptons, it could be the power supply board, so i ordered one on ebay.

When the psu board arriver, i mounted it on the tv, and nothing..

Well, i gave up and took it to a local reapair shop to ask for quotes, and he told me it needed to take a Y and the t-con boards, and gave me a crazy quote for the repair that i could with the same value just buy another used one just like mine. So i paid him for the checking and left there my old psu board asking him just to check if it was ok, because for the looks of it, it should be ok, since it had just the same symptons with the new board. Some days latter i came back there to ask him about the psu board condition and he came with excuses saying he sent it to the trash, he said he understood i told him it was broken.. he was lying.. i think that for sure he used it to fix another samsung plasma that he had there fixing that when i when there with mine he told me it had a psu problem just like mine.. i should know better, in the past i already had seen he was too expensive and a cheater, but i thought i should give it another try.. ok.. that went well..

well, i ordered new y and t-con boards and while i waited them to arrive, i took the opportunity to check the components on the old boards. for the looks of it, the Y-main board has some mosfets burned. but the t-con didnt look to have any problem, but what the hell i got one for cheap. I also checked the Y sustain buffer board as in the Tom66 video http://www.youtube.com/watch?v=51SZsfH60EY and it looked ok.

Whell, the waiting was really hard for the boards to arrive, but when they did, the i checked the Y board for burned mosfets and everything ok, so i mounted everything up.. deception.. it kept on clicking for around 4 or 5 times and then stopped fully disconnected and only with the fixed red led just as before, but at least now the remote turns on the tv, even if she turns off after 10 or 15 seconds but hey.. that”s something.. lol..

i took the y board out and now it has shorted mosfets.. and i think the psu has also some now..

Some thing to consider, the Y-Main board was exactly the same part number, date and version, but had some things a bit different from my original one, mine had some more caps, can the new one coming from the uk be incompatible??

Some measurements:

Factory sticker values say:

Va = 55v
Vs = 211v
Vsc = -185v
Ve = 83v
2Ve = 74

With everyting mounted, when turning on the tv, until i had only about 10 or 15 seconds until it turned off, but even then here is the 10/15 second measurements:
Va= nothing
Vs= 22v
Vg=15,5v

without the X-board

the same 10/15seconds on/off

Va= nothing
Vs= 22v
Vg=15,5v

without the Y and X boards (when disconnecting the Y, as the X is connected to the Y, they are both disconnected)

Va= 56,7v
Vs= 219v
Vg=15,5v

Well.. now i”m stuck without knowing what else to do or try.. and my boards, are they fixable? if i change the mosfets, check the caps and change any burned caps, will it do to fix them? or will i have to order new one's??

Thanks for reading and for any help!

Best regards everyone

[tom66]

Re: Samsung PS50C550 screen not powering

Can you post a picture of the chassis layout and one of each board?

[ViperRunner]

Re: Samsung PS50C550 screen not powering

Can you post a picture of the chassis layout and one of each board?

Thanks for the quick answer!

Here are the images! If you need anything else please just say!

Best regards

[tom66]

Re: Samsung PS50C550 screen not powering

Unplug this connector here. Does Va rise to rated 55V? Does the screen glow?

[Note: Do -NOT- re-connect this while the panel is powered up!! Doing so will permanently damage the plasma panel.]

[ViperRunner]

Re: Samsung PS50C550 screen not powering

Unplug this connector here. Does Va rise to rated 55V? Does the screen glow?

[Note: Do -NOT- re-connect this while the panel is powered up!! Doing so will permanently damage the plasma panel.]

With everything the rest connected except for that small plug right?

The Va keeps not giving any value and no glow in the panel.

Best regards

[ViperRunner]

Re: Samsung PS50C550 screen not powering

Can someone please help?

[tom66]

Re: Samsung PS50C550 screen not powering

With everything the rest connected except for that small plug right?

The Va keeps not giving any value and no glow in the panel.

Best regards

Everything except that connector. So from what you have said I would consider a Y-main or X-main issue; most likely Y-main.

[ViperRunner]

Re: Samsung PS50C550 screen not powering

Everything except that connector. So from what you have said I would consider a Y-main or X-main issue; most likely Y-main.

But has i said before, i already replaced the y-main, and it shorted.

And for what it looks like, the psu board looks to have some mosfets also shorted now.

Best regards

[tom66]

Re: Samsung PS50C550 screen not powering

So, you may have had a bad X-main, replacing both of them at the same time is often required. If the PSU outputs Vs/Va with boards disconnected, then I'd say it probably -doesn't- have any shorted FETs.

[tw2005]

Re: Samsung PS50C550 screen not powering

Like Tom says, Y & X can take each other out. Just did a 42C451 today, tried to be clever with it working out which board and what parts. they just kept blowing each other up. Did the 3 board swapout, Y,X & buffer.

That fixed mine, original buffer ended up ok.

Also I believe you can earth the blue wire on the harness connector from the PSU to the main board to start the PSU. I could on mine, voltages were there. The Y , X and main were not connected.

I think also with the X & Y disconnected including the ribbons to the logic board mine started up and I could measure the voltages.

[ViperRunner]

Re: Samsung PS50C550 screen not powering

So, you may have had a bad X-main, replacing both of them at the same time is often required. If the PSU outputs Vs/Va with boards disconnected, then I'd say it probably -doesn't- have any shorted FETs.

Hi again Tom, and thank you so much for all the quick answers!

Yes, with the x and y mains disconnected from the psu board it is able to measure correct Vs and Va. If they are disconnected form the psu, but still connected to the logic board, it is able to measure the correct voltages but in they start to fall right after started up, untill we finally ear the click on the psu board relay disconnecting and connecting again and again starting to drop voltages.

if the x and y are disconnected, both form the psu board and logic board when turning on the tv, we ear the rellay click and are able to measure the correct Vs and Va voltages that keep steady for around 15 seconds untill i ear the psu board relay disconnect and connect again and the voltages are able to be correctly measured for the 15 seconds.. and this goes on and on and on...

Best regards

[ViperRunner]

Re: Samsung PS50C550 screen not powering

Like Tom says, Y & X can take each other out. Just did a 42C451 today, tried to be clever with it working out which board and what parts. they just kept blowing each other up. Did the 3 board swapout, Y,X & buffer.

That fixed mine, original buffer ended up ok.

Also I believe you can earth the blue wire on the harness connector from the PSU to the main board to start the PSU. I could on mine, voltages were there. The Y , X and main were not connected.

I think also with the X & Y disconnected including the ribbons to the logic board mine started up and I could measure the voltages.

I tested how tom told me to do, with the x and y disconnected from both the psu and tcon and indeed the voltages where there. Wasn't counting on that, because with the diode check function on the multimeter, the psu looked has it had some shorted mosfets.. are they able to look shorted and being not??

and in the y and x boards, are they fixable? or are they trash? do i have to get new ones?? as also the y buffer board?

Thanks for the answers!!

Best regards

[tw2005]

Re: Samsung PS50C550 screen not powering

I don't mind having a go at component level however those boards are covered in a fairly heavy duty lacquer and I suspect some of the smd parts fail. I could not clearly identify them so apart from making a futile attempt at replacing the transistors which simply blew again on both the X & Y boards I just got new boards.

I was lucky because they were cheaper than components, it simply made no sense to try any harder to repair the board.

It seems the only way is to replace them at once. As for the buffer, you could do a basic test between gnd and the outputs at the ribbon connectors for shorts.

I decided not to chance it and got the buffer as well although it turned out the old one was ok, I did not find any shorts and I have put it in and is fine but only after I compared every pin to the new board.

The buffer was twice the price of the sustain boards. Interestingly, here in australia I could have gotten a Y new genuine from Samsung for only $38 delivered, The X and buffer were over a $100 ea! Makes me wonder if the Y had a problem and Samsung was selling them cheap to look after their customers? Who knows, it makes no sense sometimes.

Taken 2 weeks to get them from the US and just was not worth taking the chance with my original buffer at first. You have to weigh up the risk/cost of trying to go too cheap and blowing the boards again or copping the extra cost for piece of mind.

Which ever way you go it's not going to be a really cheap fix but should be cheaper than buying a new TV.

I had a quick look in Ebay, there's a Y & X board package 35GBP + 10 for postage to portugal. You just have to hope you get good boards, that's the only risk for that one. Don't know what that converts to in your currency.

There are some fairly cheap y boards on their own but the 3 boards ?? Don't know how that will add up.

http://www.ebay.com.au/itm/LG-YSUS-Z...item27d456c1ad

Justy doing quick searches, you'll have to be sure they're compatible.
http://www.ebay.co.uk/itm/SAMSUNG-PL...item4ab319ce02

Sometimes the seller appears not to ship international, always pays to ask and get quote for shipping. Sometimes you can be nicely surprised.

Good Luck.

[ViperRunner]

Re: Samsung PS50C550 screen not powering

I don't mind having a go at component level however those boards are covered in a fairly heavy duty lacquer and I suspect some of the smd parts fail. I could not clearly identify them so apart from making a futile attempt at replacing the transistors which simply blew again on both the X & Y boards I just got new boards.

I was lucky because they were cheaper than components, it simply made no sense to try any harder to repair the board.

It seems the only way is to replace them at once. As for the buffer, you could do a basic test between gnd and the outputs at the ribbon connectors for shorts.

I decided not to chance it and got the buffer as well although it turned out the old one was ok, I did not find any shorts and I have put it in and is fine but only after I compared every pin to the new board.

The buffer was twice the price of the sustain boards. Interestingly, here in australia I could have gotten a Y new genuine from Samsung for only $38 delivered, The X and buffer were over a $100 ea! Makes me wonder if the Y had a problem and Samsung was selling them cheap to look after their customers? Who knows, it makes no sense sometimes.

Taken 2 weeks to get them from the US and just was not worth taking the chance with my original buffer at first. You have to weigh up the risk/cost of trying to go too cheap and blowing the boards again or copping the extra cost for piece of mind.

Which ever way you go it's not going to be a really cheap fix but should be cheaper than buying a new TV.

I had a quick look in Ebay, there's a Y & X board package 35GBP + 10 for postage to portugal. You just have to hope you get good boards, that's the only risk for that one. Don't know what that converts to in your currency.

There are some fairly cheap y boards on their own but the 3 boards ?? Don't know how that will add up.

http://www.ebay.com.au/itm/LG-YSUS-Z...item27d456c1ad

Justy doing quick searches, you'll have to be sure they're compatible.
http://www.ebay.co.uk/itm/SAMSUNG-PL...item4ab319ce02

Sometimes the seller appears not to ship international, always pays to ask and get quote for shipping. Sometimes you can be nicely surprised.

Good Luck.

Thanks for the quick answer!

The x-main of that kit is for HD and mine is a FHD. mine has 2 panel inputs, whereas that one has only one. One more thing, do you know if my pane is compatible with the 3D version of this tv??

I found one PS50C7000 with a broken panel, and it was quite cheap! if my panel was compatible, it may worth making the buy.

Best regards

[tw2005]

Re: Samsung PS50C550 screen not powering

Ah, ok I did not realise, looked the same pcb. I find Shopjimmy website is a wealth of info on what is compatible. Do a search on there and look at the panel numbers they list.

[ViperRunner]

Re: Samsung PS50C550 screen not powering

Already replaced the Y and X Boards, as well the y sustain buffer board and the t-con, and it didn't resolved. It keeps doing the click click sound and not turning on

Can someone give me any tip aboput what may be going wrong?

regards

[freakaftr8]

Re: Samsung PS50C550 screen not powering

I would say now that there is a panel incompatibility issue you are having. When you swapped the boards did you examine the panel labels to make sure that they match part number wise? Also in panel voltages? Were the panel voltages close match with each other? Also between the two logic boards. You call them tcon but do the part numbers match?

[ViperRunner]

Re: Samsung PS50C550 screen not powering

I would say now that there is a panel incompatibility issue you are having. When you swapped the boards did you examine the panel labels to make sure that they match part number wise? Also in panel voltages? Were the panel voltages close match with each other? Also between the two logic boards. You call them tcon but do the part numbers match?

Thanks for the quick reply freakaftr8!

The set of boards where taken from a working tv with the same panel reference.

Yes, the part numbers are all the same, as also the date and reference numbers of all the boards

Thanks.

Regards