Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

[Jeremie]

I bought this TV new back in 2012 and it worked well for the first couple of years. Just over a year ago it started to randomly turn off and then back on while using it. It was replaced by another Samsung TV that was a couple years newer and wasn't used very much after that. The problem mainly occurs when using an external input.... i.e. an HDMI cable or cable TV source, it almost never happens when streaming movies on Netflix.

I took it apart today and noticed 3 burned connectors on the P/S to M/B connector and damage to the cable on that end as well. I'm wondering if just replacing the P/S board and Cable will fix the problem or if that issue was cause by the M/B cycling the TV on and off frequently causing the connections to burn out.

I'm new to TV repairs, so any advice you can give me will be greatly appreciated.

J.

[freakaftr8]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Can you show us a picture of this? Something doesn't sound right. Connector should not burn unless its making a shotty connection on the backside of that board

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Here are some pictures of what I found. The bottom of the board appears to be normal.

[freakaftr8]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Looks like the 13v to the BU board. Can you confirm on the mainboard that pin 10 13v is not shorting to ground on that board?

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Let me pull that board and take a look at it.

[ReeceyBurger123]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Check out this video by badcaps user Tom66 very common on these:

https://m.youtube.com/watch?v=bJdDsxxxn2U

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

The mainboard shows no signs of a short on it anywhere, everything looks clean.

[Agent24]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

It could even be that pin was loose and heated up from high current going through a loose connection, causing the connector to be damaged and the TV to drop out.

Since the TV still works mostly, there probably are not shorted parts. Maybe with Netflix only it draws less power so the dodgy connector doesn't come into play.

I would replace the connector and cable, ensuring they are well connected and see what happens.

[freakaftr8]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Or in a pinch you could get by and cut the wire off of the harness and carefully solder it to the back side of the mobo for pin 10 since the harness connector is already bad and see if that straightens you out

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Any idea where I might be able to get a replacement connector from? I really have no idea what I need to search for to find the right part.

[ReeceyBurger123]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

You probably wont be able to find one, do what freak says and what is shown in the video. More reliable !

[budm]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Pin 7 and 9 carry the 13V (They use two wires for reason), so may be pin 7 is not carrying the current due to bad/open connection so most of the current is flowing though pin 9 instead. Check the the connection on pin 7. I would solder the wire as suggested.

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

So, I got out my multi meter and it seems pins 7,9 and 10 all have continuity with each other. Where would I look to find out if this is normal? Also, when I touch the connection for any one of these pins on the back of the board and then any other pin on the top row I get momentary continuity, and then an open circuit....is this normal?

[budm]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

According to the chart as printed on the board pin 10 is also for the same B13V as for pin 7 and 9, so that is correct.
So do you have 13V on those pins when TV is ON?

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

I haven't actually plugged it in since I took it apart this morning. I'll put the boards back in it and see what I have for voltages at those pins.

[freakaftr8]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

That would probably be the best option. If you can find a way to strip pins 7 9 and 10 off the connector to find a way to solder them directly to the corresponding connections on the board that may be your best bet for a long term solution. You have to be really careful to make sure you get the right wires on the right pins and solder the wires to the proper areas of the board. If you don't feel comfortable with soldering those wires to the underside where the pin connectors are soldered into the board you could trace the tracks to a suitable location on the board and you may have to add some extension wire to the wires at you clip off of the connector. All you have to do is follow the traces from the underside where the connector pins go to an area that you can solder the wire to that will not interfere with any other connection. Hopefully that makes sense. At least this is what I would do in this situation

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

That makes sense.....I may give that a try. I just put the boards back in it and checked the voltages. I have 12.76 volts at pins 7 and 9 on the P/S board and 12.70 volts on those same pins on the mainboard side. I couldn't get to pin 10 to check that voltage.

Also there is a dark section at the top of the screen that extends from the top of the screen down 6 inches and then the picture is normal again. It's like there is a shadow over that section of the screen. The picture is still active in that area, it's just darker the higher up the screen you go....Any ideas on how to fix this issue as well?

[freakaftr8]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Once you solder those wires and get this TV up and running take a picture of the screen so we can see the fault. It sounds like a backlight issue possibly and these D series are very well known for backlight issues

[kartwood]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

The p.n. for this cable ass'y is: BN39-01479A.

A local Samsung parts dist or ASC should be able to get one for you.

[Jeremie]

Re: Samsung UN55D7000FLXA cycles on/off P/S to M/B cable appears to be damaged

Thanks for the part number, not sure I'll need it now though.

I've soldered the wires to the connector and have the TV working again. Attached is a picture of the dark area at the top of the screen.

As soon as I started playing a movie from my PS3 the TV started to cycle on and off. I noticed that it seemed to coincide with every time the screen went black, the TV would power off. As long as there was a picture on the screen it remains on with no issues, if the screen goes black between scene changes or after the piracy warning the TV power cycles. Any idea on what could be causing this behavior?