samsung on off issue

[FishFind]

1I have a Samsung pn50a550s1fxza. That has the power board bn44-00222a

My Tv takes about 15-30 minutes to turn on. It will cycle on and off on its own when attempting to start. When it does start it will stay on untill I shut it off. I can leave it all day and it wont shut off. I have read that caps may be an issue. I took a look and all of mine look fine. I replaced all the 1000uf and 2200uf for good measure but did nothing. I did see that I had one cap that was blown apart and that was one labeled 4700 j 400mkt. It was the top one out of the two. I replaced it with a .0047 500v that I found at a shop near me. I can get power to the tv when all the plugs are taken off the power supply board except the one cluster of wires that has 12 pins on top and bottom. So 24 wires total. This is the wire harness that goes to the inputs board where you connect the hdmi,svid and such. When I take this wire off I get 0 power at the main wires or vs, anywhere.

I have checked the volts on every pin against the specks on the board and everything is where it needs to be even the vg, and vs voltage. This is when tv is up and running and when it is doing its on off cycle. I notice the top right transformer is buzzing a little.

The two wire plug that comes from the power supply has 58-61 volts on both sides of the wire "one blue one brown" when I use the chassis as a ground. The fuse that is close to the two wire connector has 64v the other two fuses have 120-130v

Any Ideas?

[Dgtech]

Re: samsung on off issue

Post pictures of the boards when you get a chance.

[FishFind]

Re: samsung on off issue

Here are some picks. Hope thay are good enough if not I can take some better ones.

[FishFind]

Re: samsung on off issue

Any thoughts?

[tom66]

Re: samsung on off issue

The pictures aren't really clear enough to see anything obviously wrong.

Try taking the photo in sunlight with macro mode enabled, if your camera has the feature.

What capacitors did you use as substitutes for the old ones?

[FishFind]

Re: samsung on off issue

I will get some better picks. Some of the caps are from raidoshack some are nichicon 1000uf 25v. I have not had a chance to take out the raidoshack yet.

[tho]

Re: samsung on off issue

Hello Fishfind.
Your problem is on the RTE-801 and RTE-802. You need to replace 2 of them the same time. The problem is value of the component. I do not know about it. I have the same problem like you. After troubleshooting . If you have a schematic, Please post on here I can share with you. Thank you.

[FishFind]

Re: samsung on off issue

Hello Fishfind.
Your problem is on the RTE-801 and RTE-802. You need to replace 2 of them the same time. The problem is value of the component. I do not know about it. I have the same problem like you. After troubleshooting . If you have a schematic, Please post on here I can share with you. Thank you.

Thank you for replying to me. I am having a hard time understanding what you are talking about. What is RTE-801 and 802.

[tho]

Re: samsung on off issue

RTE-801 and 802. Look at the component the side is about 1 cent and color is green. It is a 2 legs and beside the leg RTE-801 and 802. on the Ebay It is cost 3 dollars each.
You ca searc on ebay type therimitor and look at the item 5ohm ,12amps ,side 20mm. Good luck. I have not to much time to get here.

[ben7]

Re: samsung on off issue

RTE-801 and 802. Look at the component the side is about 1 cent and color is green. It is a 2 legs and beside the leg RTE-801 and 802. on the Ebay It is cost 3 dollars each.
You ca searc on ebay type therimitor and look at the item 5ohm ,12amps ,side 20mm. Good luck. I have not to much time to get here.

What I think your saying is, RTE-801 and RTE-802 are NTC's?

[freakaftr8]

Re: samsung on off issue

I remember working on a 42" Samsung last year build date of 2007 sorrydont remember model number. It was a cold solder joint on a MOSFET in the power supply caused this exact same symptom.

[FishFind]

Re: samsung on off issue

Why do you sat rte-801 and rte802 are bad?? they look good. What is it that they do?

Here are some better picks.

[tom66]

Re: samsung on off issue

Those devices limit the charging current the capacitors draw so breakers and fuses don't pop when the TV is turned on from cold.

You need to look underneath your power supply. Solder joints should appear somewhat shiny, with a volcanic shape. If the joint appears like a ball on top, and appears dull or white-tinted, it is a cold joint. Reflow it with solder and soldering iron.

[FishFind]

Re: samsung on off issue

Ok took a look and fixed everything I thought looked odd. No effect. I did not change the rye801 or rye802. Do I need to? What now?

[gilly1984]

Re: samsung on off issue

Can we have a nice clear pic of the underside too please.

[tho]

Re: samsung on off issue

Hello fishFind.
I m so sorry to make you comfuse about it. I have no time to get up here until now.
I just want you to clear about it. Look on the picture you posted from point b to piont A and go to the end of the heat sink. do you see the rte-801 and rte-802 ? The next to rte-801 and rte-802 is 2 relay (that is the switch, SDT it is call is single fold double through , black color) go to next is the input power conector. It is 2 pin, righ? .The problem is right there. The power ac input from the connector , 2 pin .It go to the relay sdt switch and from the switch go to the rte-801 and rte-802 and from the point rte 801 and rte-802 to the diot, Righ? If the pin on the sdt cold solder or open . It will burn the rte 801 and 802. or if the the 2 relay (sdt shorted, It will not use the remote control to turn it off, or on. In my case, the rte801 and rte 802 was burn, I troubleshooting from the ac input to the relay (sdt) I found the the 1 pin on the sdt (relay) is cold solder so it make the rte hot and it up. I check the number on the rte 801 and 802 the value is SCK0512 that mean 5 ohm and 12amp and diameter is 20mm. I replace it. It is work ok now.

[tho]

Re: samsung on off issue

I will be back to let you know more about it. Good luck O Please use the meter to check the how many ohm on rte-801 and 802? SCK801 and SCK-802 is mean Power Thermistor for limiting inrush current . SCK0512 can handle maximum current up to 12amp and operating temperature up to 150 dregree c. It is very hot. do not put your hand on it when power on.

[budm]

Re: samsung on off issue

I think THo is trying to say is that the relay is SPDT (Single Pole Double throw).
The relay contacts will close to bypass the inrush current limiter RTE801 and RTE802, if the relays fail to bypass the limiters, they will get very hot.
I am not sure that is the problem you are having, and we still do not get to see good clear pictures of the bottom side of the board yet.
I also believe the relays may be just a SPST (Single Pole Single Throw) type relays, cannot tell unless we can see the bottom side of the board or the P/N as printed on the relays.

And by the way "The two wire plug that comes from the power supply has 58-61 volts on both sides of the wire "one blue one brown" when I use the chassis as a ground."
When you work in the primary side, you do not use the chassis safety ground as a ref ground point for primary side. If you want to check the AC voltage feeding the circuit, you will measure between Hot (Black or Brown) and Neutral (White or Blue) and you DO NOT WANT TO TOUCH AND PART OF THE TV with your body while you are doing this. The DC circuit ground for the primary side will be the negative side of the large DC (350~450VDC) filter cap.

[FishFind]

Re: samsung on off issue

Thanks guys. I will get some picks of the bottom when I can. I put the board back in so I can use the tv un-till I fix it. Here is something that I did notice that may hold a clue. If I have the tv on a input that I am not using like pc it will start much faster like 1st or second attempt. I noticed it will always start much faster if it is a black screen with no image.

Also I never said before but when it is starting and failing it will sometimes have a very distorted screen "black, snow, green, pink." and a loud pitch squeal from the speakers.

[tom66]

Re: samsung on off issue

That would make a lot of sense - plasma displays use much less power on black scenes, so if those NTCs are in series, they will drop less voltage and TV may be able to work.

I have a variac (variable transformer) at home and played around with an LCD on it, found it would work down to 60V, before it started flickering badly. I have not tried a plasma display yet.