Samsung Plasma problem PN60F5350AFXZA

[Jerryv]

Trying to help out a friend with a Samsung plasma that quit working. It is only a couple of years old. I am not familiar with plasma TV's at all, but I have had some success fixing various electronics so I thought I would give it a try. He had replaced the power supply and the main board, but then gave up. When you plug it in and hit the power button, it turns on the red power indicator and there is a green led on the main board that blinks slowly. No picture or sound. I have not seen one of these operate so I don't know if there is supposed to be a startup sound or not.

Couldn't find a service manual for this specific model, but after doing some research I checked the voltages listed on the panel and found some problems on the Y-sustain board. After replacing some IGBT's and Mosfets, the Vs, Va, Vsc, and Ve voltages at the test points now match the label values, but only briefly after pressing the power button. Then they slowly bleed down to zero. To test again I have to unplug the set, wait a few seconds, plug it in, and hit the power button again.

I see another test point on the Y-sustain board marked Outl, but I am not sure what voltage should be on it. I measure zero volts there.

The layout of the boards is similar to this thread:

https://www.badcaps.net/forum/showthread.php?t=46458

Any help would be appreciated.

Jerry

[Regor]

Re: Samsung Plasma problem PN60F5350AFXZA

Bump. Your problem is same as mine; the PS is shutting down to protect the circuit. I've troubleshot and I believe there is a short in 1 of 3 boards; y-main, y-buffers, or x-main. Good luck and I'll keep watching here for ideas from those smarter than me (which is most everyone).

[tom66]

Re: Samsung Plasma problem PN60F5350AFXZA

Check the screen very carefully for small cracks, such cracks can cause this fault and unfortunately they would render the TV unrepairable

[Hamie]

Re: Samsung Plasma problem PN60F5350AFXZA

Are you saying the layout is exactly like the other thread?

Ie: no control board.

If so you need to check the critical voltages.

VS and VA located on the power supply.

VSC (Vscan) located on the y-sustain

VE located on the z-sus

There should be test points.

All voltages may only appear momentarily, so you might need to turn the tv off and on and quickly check each point.

[Jerryv]

Re: Samsung Plasma problem PN60F5350AFXZA

Are you saying the layout is exactly like the other thread?

Ie: no control board.

If so you need to check the critical voltages.

VS and VA located on the power supply.

VSC (Vscan) located on the y-sustain

VE located on the z-sus

There should be test points.

All voltages may only appear momentarily, so you might need to turn the tv off and on and quickly check each point.

Yes, I saw the label on the panel and found the test points. Initially the Vs wasn't working because of a shorted IGBT and the Ve wasn't because of a faulty Mosfet. I changed those and now the voltages are:

Vs label 208 actual 209 momentarily at power on then drops slowly
Va label 57 actual 56 "
Vsc label -195 actual -195.5 "
Ve label 113 actual 112 "

If I understand the names correctly, there is no control board.

I tried to get some pictures. Poor light and flash glare, but you can see the layout.

I will try to flip it over and check carefully for cracks. Would a crack cause the power supply to go into protection?

Jerry

[tom66]

Re: Samsung Plasma problem PN60F5350AFXZA

A crack will cause a failure to sustain, which will trigger a shutdown.

[Jerryv]

Re: Samsung Plasma problem PN60F5350AFXZA

A crack will cause a failure to sustain, which will trigger a shutdown.

I didn't take the front bezel completely off, but I lifted it and checked all the way around the edges. I don't see any cracks or imperfections in the glass. Are there any special ways of checking for them? Would a problem with the Y buffer boards cause this symptom?

Thanks
Jerry

[Regor]

Re: Samsung Plasma problem PN60F5350AFXZA

I didn't take the front bezel completely off, but I lifted it and checked all the way around the edges. I don't see any cracks or imperfections in the glass. Are there any special ways of checking for them? Would a problem with the Y buffer boards cause this symptom?

Thanks
Jerry

A short in any of the boards could cause power supply to shut down like yours is. I would try taking the suspected board off and outing in freezer for a hour and then re-install. I would try Y-main first, then X-main.

[freakaftr8]

Re: Samsung Plasma problem PN60F5350AFXZA

Try disconnecting both upper and lower buffer boards and power up. Does it stay on now?

[tucocaps]

Re: Samsung Plasma problem PN60F5350AFXZA

Thanks for the posts. I happen to be working on one of these at the moment.

It's a cracked/damaged screen. I am still trying to "learn" plasmas, mostly for the sake of salvaging parts.

I notice that I have standby, and if I short PS-on to ground, the power supply will turn on and stay on. However, the mainboard appears to turn on for a few seconds, then off. This is the same action with/without the PS forced on. I know it may have been asked before, but is there any way in cases like this, to "trick" the set into allowing the mainboard to power on for purposes of testing sound and so on?

I also notice that if I disconnect the power cable running to the Y-main (but leave the X connected), then I have (i think) over 200v at VS at start up. This slowly fades down to about 12 volts. If Y-main is connected, it is at 12 volts all the time. Would this be normal in the case there is something wrong with the y-main and/or the panel is damaged? Does it fade because there is no load on it?

[Jerryv]

Re: Samsung Plasma problem PN60F5350AFXZA

Try disconnecting both upper and lower buffer boards and power up. Does it stay on now?

I thought I would try checking them for shorts so I took them out. Not sure exactly which pins to check but I didn't find anything conclusive.

Those connectors to the Y-main board are annoying, but I got them apart again without damaging them.

With the buffer boards out, the voltages still do not stay on, but I did notice a slightly different behavior. When I plug in the power, the red LED on the front stays on. Then when I hit the power button, it goes out, blinks twice, slowly blinks ten times, and then gives two more quicker blinks. Is this some sort of code? Maybe it was doing this before and I just didn't notice it. The green LED on the Main board just continues to blink slowly.

Tucocaps: When mine was not producing the Vs voltage momentarily, I found that one of the IGBT's in the upper left of the Y-main board was shorted. I replaced both and then started getting the 208V momentarily each time it turned on. I have not tried shorting the PS-on for fear of blowing something out again.

Jerry

[freakaftr8]

Re: Samsung Plasma problem PN60F5350AFXZA

Samsung's do not implement a error code in there red stand by light what you're seeing is some kind of over current protection being trip or something to that nature. This could be a number of things. Have you tried running it with no buffer boards and disconnecting the X board?

[ned1]

Re: Samsung Plasma problem PN60F5350AFXZA

You may try to disconnect Y sustain and Z main board from the power supply and see if the power supply still shuts off.

[tucocaps]

Re: Samsung Plasma problem PN60F5350AFXZA

I thought I would try checking them for shorts so I took them out. Not sure exactly which pins to check but I didn't find anything conclusive.

Those connectors to the Y-main board are annoying, but I got them apart again without damaging them.

With the buffer boards out, the voltages still do not stay on, but I did notice a slightly different behavior. When I plug in the power, the red LED on the front stays on. Then when I hit the power button, it goes out, blinks twice, slowly blinks ten times, and then gives two more quicker blinks. Is this some sort of code? Maybe it was doing this before and I just didn't notice it. The green LED on the Main board just continues to blink slowly.

Tucocaps: When mine was not producing the Vs voltage momentarily, I found that one of the IGBT's in the upper left of the Y-main board was shorted. I replaced both and then started getting the 208V momentarily each time it turned on. I have not tried shorting the PS-on for fear of blowing something out again.

Jerry

I think mine is at about 190, and then falls. I just want to know if this is normal with no load on VS. In this case, I don't care about saving or fixing any boards, but just taking the PS and the main , and hopefully being able to test them to the extent I can assume they are probably OK.

I notice there are two outputs labelled VS, so I'm also wondering if I load test those with lightbulbs, if I need to connect to both , or just one.

[freakaftr8]

Re: Samsung Plasma problem PN60F5350AFXZA

Your power supply is sending vs output so I think it's okay have you tried only one buffer board at a time?

[tucocaps]

Re: Samsung Plasma problem PN60F5350AFXZA

Your power supply is sending vs output so I think it's okay have you tried only one buffer board at a time?

I have tried disconnecting both buffers, but not just one. I think I get VS over 180 at plugin with both buffers disconnected, and no PS-ON jumpered. So, as expected, the short/problem is likely at the buffers/panel. The question is how to bypass, which always seems to be difficult with plasma.

I'm confused about the main board action, even when PS is forced on. Why does it turn off? I determine it turns off, because no sound, and I can see the optical out light up for several seconds, then off. Does this mean the board is bad, or is there some other shutdown condition still taking place?

[freakaftr8]

Re: Samsung Plasma problem PN60F5350AFXZA

Well the system may be designed to shut down at no load is detected or if a overload is detected so you might want to try one at a time

[tucocaps]

Re: Samsung Plasma problem PN60F5350AFXZA

Tried one at a time, but same result. I didn't reconnect the panel ribbons.

The PDP is quite damaged, so I'm not sure this would work anyway?

[Jerryv]

Re: Samsung Plasma problem PN60F5350AFXZA

Thought I should update this thread and close it out.

I sort of dropped it when I got busy with other things last fall and the thread kind of got hijacked. Two weeks ago I started looking at it again. Disconnecting things doesn't seem to help at all on these sets. There must be feedback that shuts the voltages down if everything isn't just right. The repairs I had made to the Y-main board got the panel voltages to work momentarily at turn on, but I still had nothing on the OutL tp as I originally mentioned so I checked the board more thoroughly and found some more shorted diodes and transistors on the back side. There is a lot of circuitry on the back side.

Giving up on the repairs, I ordered a replacement board on eBay that supposedly came from a set with a broken screen. With some skepticism, when it arrived, I checked the parts that appeared bad on the original and found no shorts so I installed it. Amazing! The TV came back to life and seems to be working 100%.

Judging from the threads on this forum, it looks to me that plasmas are more complicated and less reliable than LCDs. Might be one reason they have gone extinct.

Thanks for the help and I hope this info may help someone else.

Jerry

[ReeceyBurger123]

Re: Samsung Plasma problem PN60F5350AFXZA

Hey hey nice fix ! But a good Plasma for example Pioneer or FHP is 100x more reliable than any top end Lcd fact Samsungs and other ones are just poorly engineered so they fail way before their expected life time