Samsung 50" Plasma, No Picture or sound

[RCFLYER]

Re: Samsung 50" Plasma, No Picture or sound

IT WORKs !!!!!!!!!! I want to thank everyone that helped especially
Tom66 and PlainBill. This is a great website!!! I love you guys.

[tom66]

Re: Samsung 50" Plasma, No Picture or sound

Awesome! Enjoy your TV.

[RCFLYER]

Re: Samsung 50" Plasma, No Picture or sound

Well I was so excited it worked that I didn't notice a shadow at the bottom of the screen. I hope this is a simple fix. I'm realy happy that it's
working though.
Please help.

[tom66]

Re: Samsung 50" Plasma, No Picture or sound

Well I was so excited it worked that I didn't notice a shadow at the bottom of the screen. I hope this is a simple fix. I'm realy happy that it's
working though.
Please help.

Loose Y driver FFC for the associated rows, disconnect and reconnect, if it still gives problem use a bit of contact cleaner in there (leave for 30 minutes for cleaner to evaporate, some are conductive.)

I had the same problem with a Panasonic plasma and it was difficult to get the connectors just right. If you didn't get them just right you would get an interlaced pattern on some rows, like in your image. There's a trick to doing it, but it varies from manufacturer to manufacturer (or even model to model.) In case it's the same as the Panasonic, you have to push it in until you feel a slight click, and then you can engage the lever to lock it in place.

Of course do this while it's switched off as those rows are energised with 400V.

[RCFLYER]

Re: Samsung 50" Plasma, No Picture or sound

You were right on Tom66. I cleaned the contacts and the Picture looks great.

Now I can say "It's fixed!",

Thanks again

[tom66]

Re: Samsung 50" Plasma, No Picture or sound

I'm glad you fixed it.

By your username, do you fly model aircraft? That is one of my hobbies too, especially the electronics side (developing an on screen display product.)

[RCFLYER]

Re: Samsung 50" Plasma, No Picture or sound

I'm glad you fixed it.

By your username, do you fly model aircraft? That is one of my hobbies too, especially the electronics side (developing an on screen display product.)

Yes, I'm President of a Club called Northwest RC in Hoffman Estates Illinois. Check out our website northwestrc.com I would like to find out more of the on screen display product.
Thanks

[netdent]

Re: Samsung 50" Plasma, No Picture or sound

I also have this tv with faulty y main, I replaced one of the fets on the left that was shorted this cured psu tripping out but remained a blank screen, would love to repair the board but have been looking for a used replacement with no luck

thanks Ronnie

[RCFLYER]

Re: Samsung 50" Plasma, No Picture or sound

I also have this tv with faulty y main, I replaced one of the fets on the left that was shorted this cured psu tripping out but remained a blank screen, would love to repair the board but have been looking for a used replacement with no luck

thanks Ronnie

Check all of the FET's on the Y sustian board, I had to replace 6 of them.

[tom66]

Re: Samsung 50" Plasma, No Picture or sound

Yes, I'm President of a Club called Northwest RC in Hoffman Estates Illinois. Check out our website northwestrc.com I would like to find out more of the on screen display product.
Thanks

http://www.rcgroups.com/forums/showt...90963&page=120

Starts at page 1... but all the interesting stuff is later on.

I'm working on the PCBs tonight.

[netdent]

Re: Samsung 50" Plasma, No Picture or sound

Check all of the FET's on the Y sustian board, I had to replace 6 of them.

That was the only one short on mine, if I remember right the solder was a pig to remove! must be high melt solder? just worried I spend loads on fets and still not work?

thanks Ronnie

[tom66]

Re: Samsung 50" Plasma, No Picture or sound

That was the only one short on mine, if I remember right the solder was a pig to remove! must be high melt solder? just worried I spend loads on fets and still not work?

thanks Ronnie

Probably lead free but the main problem is going to be the heatsinks and the large traces leading out of the devices. It may be helpful to remove the heatsinks first.

[RCFLYER]

Re: Samsung 50" Plasma, No Picture or sound

Well, bad news. It worked fine for about 10 hours then stopped working.
Same clicking noise. I checked the Y sustain board and 4 Mosfet's were shorted on the first heatsink and 1 on the second heatsink. What can be shorting these out?

[tom66]

Re: Samsung 50" Plasma, No Picture or sound

Well, bad news. It worked fine for about 10 hours then stopped working.
Same clicking noise. I checked the Y sustain board and 4 Mosfet's were shorted on the first heatsink and 1 on the second heatsink. What can be shorting these out?

That sucks. Were the same devices failed? It's quite possible they did not have good thermal contact. Did you use thermal paste? What type of paste did you use? I've not heard of a plasma TV blow them after just 10 hours. Maybe after 10 seconds, or after a year, but 10 hours seems like it's past the early failure point but too early for a wear-out failure.

[RCFLYER]

Re: Samsung 50" Plasma, No Picture or sound

That sucks. Were the same devices failed? It's quite possible they did not have good thermal contact. Did you use thermal paste? What type of paste did you use? I've not heard of a plasma TV blow them after just 10 hours. Maybe after 10 seconds, or after a year, but 10 hours seems like it's past the early failure point but too early for a wear-out failure.

The first four were replaced. I used thermal paste from Radio Shack

[tom66]

Re: Samsung 50" Plasma, No Picture or sound

The first four were replaced. I used thermal paste from Radio Shack

I've never used Radio Shack thermal paste but I'm going to guess it isn't the most optimal stuff. Do you have a photo of how you mounted these devices?

[lebthug]

Re: Samsung 50" Plasma, No Picture or sound

Hi! Sorry to reopen an old thread but I have a similar TV (PN51D550) with possibly the same exact problem. I'm just not home to check the MOSFETs for shorts, but my X board when plugged causes a short on Vs.

If I unplug the Y (and the X since it's connected through the Y), I get proper Vs and Va values.
If everything is plugged in, I get 6 clicking cycles then unresponsiveness, and 0V on both Vs and Va.

I tested for shorts while the TV is unplugged and I get a short on Vs as long as X board is plugged in, no short otherwise.

I was wondering if the problem was resolved due to bad thermal contact or if it's potentially useless to replace the shorted MOSFETs because they will fail again.

It seems like reliable TVs are well behind us All I hear about is broken TVs everywhere, and I'd like to fix mine with better components if I can instead of replacing failed parts with harvested parts that are bound to fail.

Thanks

edit: not exact same TV, got lost reading too many threads!

[j33jared]

Re: Samsung 50" Plasma, No Picture or sound

I also have a similar problem. When I plug my tv in it clicks like it is going to turn on and then clicks several seconds later like it is turning back off. The picture and sound never come on. It will do this until unplugged. Click on, click off, click on, click off. Hitting the buttons will not do anything for it.

[rogerazambuja]

Re: Samsung 50" Plasma, No Picture or sound

Hi guys. I have the Brazilian model of this set, PL51D550. Yesterday I was watching TV then suddenly a loud sound of shot come from the television and then picture was gone. Only audio works now.
I had tested all voltages on the boards and checked for broken capacitors but i didn't found anything wrong. The led on logic board blinks indicating that everything is fine, but the self test that is supposed to show some image patterns on the screen don't work.
Any suggestions?

[david j]

Re: Samsung 50" Plasma, No Picture or sound

i have the same problem with mine to same model ps50b450 turns on and melody sound 5 blinks on standby light stays ok on then nothing done the y main test and x main still the same changed main board changed power board but i did notice no flashing led light on the logic board i have posted help but not had a reply so i saw yours in a search on the net and hope to get help like you did