Announcement

Collapse
No announcement yet.

Samsung PN51D7000FF cycling off and on

Collapse
X
Collapse
 
  • Page of 3
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 3 template Next
    #1

    Samsung PN51D7000FF cycling off and on

    I have a Samsung PN51D7000FF that over the weekend started cycling off then back on again. It generally runs for 2-3 minutes then powers off and back on. This continues no matter how long the TV is left on. Turnaround time on the cycle (on -> off -> on with picture and sound again) seems to be 5-6 seconds. None of the caps are swollen or visibly leaking. The only fuse I see is on the power board, and I assume it is OK because the TV powers on still. I verified that disconnecting the board with the power button does not improve the situation. Picture and sound quality are still good and seem to be unaffected by whatever the problem is.

    I am going to snag a digital meter from work tomorrow so I can verify my assumption about the fuse and start looking at voltages.

    Any help/advice anyone can provide would be greatly appreciated.

    -Jason
    Tags: None
    #2
    Re: Samsung PN51D7000FF cycling off and on

    So i got the meter from work today and measured what I gather are the key voltages based on my research here and in the quick service manual. Voltage info sticker and board images are now attached.

    Va = 58.3
    Vs = 207.9
    Ve = 79.7
    VSC = -186.2

    Incase any of these might be useful:

    STBY 5V=5.25 while the tv is off
    PS_ON= 0.165 while the tv is on, 3.325 while the tv is off
    VS_ON = 3.262 while the TV is on, 0 while the TV is off

    Once again any assistance anyone could provide is appreciated.

    - Jason
    Attached Files

    Comment

      #3
      Re: Samsung PN51D7000FF cycling off and on

      After more discussions with some electronics guys around the office they asked me to check if the 5VSB flicks off when the TV cycles. They suggested that behavior might point to the power board. When I tested the standby voltage does not vary even .01v during a cycle (at least not in a time frame my meter is able to display). Any chance that means the main board may be causing the power cycle?

      Thanks.

      Comment

        #4
        Re: Samsung PN51D7000FF cycling off and on

        Check the solder joints on the Psu, look for cracked joints on devices mounted to the heatsinks.
        Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

        https://www.facebook.com/Telford-Tel...7894576335359/

        Comment

          #5
          Re: Samsung PN51D7000FF cycling off and on

          Thanks very much for the suggestion. I unmounted the PSU board and carefully looked over all of the joints. I was unable to find any cracks. In particular the larger joints connecting whatever those are under the heatsinks looked solid. Anything else that I might be able to check?

          - Jason

          Comment

            #6
            Re: Samsung PN51D7000FF cycling off and on

            I wanted to post that I found a resolution for my problem. I was able to confirm by working with a local repair shop that the main board was bad. Unfortunately I am unable to find a replacement, but maybe someone else can benefit from this information.

            PS - If anyone happens to know where I could get a main board I would appreciate the info. I cant afford an OLED TV atm, and my TV is setup in a room with no windows/natural light so i need something with those deep blacks.
            Last edited by JayTheSpaz; 11-11-2015, 08:36 AM.

            Comment

              #7
              Re: Samsung PN51D7000FF cycling off and on

              One last post in case this helps anyone else. I was able to fix my TV using the main board from a PN51D8000FF/FFXZA. The board was not documented as compatible with my TV so YMMV. I compared all the other boards in my TV, and they were listed as compatible replacements for the D8000. I took a gamble and ordered a model BN94-04402C board, which as it turns out does work in my TV.

              Comment

                #8
                Re: Samsung PN51D7000FF cycling off and on

                (I know this is an old post, sorry to revive it, but need some help)

                Jay,

                I have the exact same TV with the exact same problem. I have done a lot of research and come to some of the same conclusions. Caps dont look to be busted on the power board. I tried unplugging the power button assembly, but still have the same problem. I got a voltage meeter in hand, but dont really know what I need to do to test what you did.

                I was thinking about ordering a replacement power supply board, but am not 100% sure that will fix my issue. How did you find out for sure that your main board was bad, and not the power supply board? You mentioned looking in the service manual. Do you have a copy of it? Thanks for any help you can provide!

                Comment

                  #9
                  Re: Samsung PN51D7000FF cycling off and on

                  bp805

                  If your tv turns on and stays for only 2-3 minutes then reboots then you more than likely have the exact same issue. One way to know for sure is to take a stopwatch and see exactly how long your set stays on for. I currently have this tv with this issue and my tv only stayed on for 1 minutes and 15 seconds every time. If your problem is coming from anywhere other than the main board then you will have a variation in your time meaning if it is an overheating issue, the tv will reboot more and more often as it keeps warming up more and more. If its a cracked solder joint, same thing. If it is a firmware issue than it will be like clock work.
                  This is a common issue on these sets, and just like Jay the spaz, I have purchased the main board BN94-04402C to replace the original one. I have not received the board yet so I can't confirm that it will work, however I will update the post as soon as it does.
                  Good luck

                  Comment

                    #10
                    Re: Samsung PN51D7000FF cycling off and on

                    NicksTVS,

                    Thanks for the reply. Depending on what I did, it was either 45 seconds until it cycled, or about 80 seconds. I with everything plugged in as normal, it cycles on/off every 79 seconds or so, like clockwork.

                    I have seen some people say they can get the tv to power cycle with the main board unplugged from the power supply board, but that did not work on mine...it would not come on at all.

                    How long have you had the tv? When did it start having issues?

                    Comment

                      #11
                      Re: Samsung PN51D7000FF cycling off and on

                      Update:

                      I tested the voltage on all of the test points (Vs, Va, Vsc, and Ve) on both the power supply board and the x and y-main boards. All voltages were within 1v of what they were supposed to be according to the sticker on the inside, except for the Vs which was 214v instead of 207v.

                      Ill take a closer look for cracked joints on the power board, but from what I have seen so far, I dont see any issues.

                      Is there a way to run some tests on the main board to try to find out if that is actually what is causing my issue? What about the firmware issue you spoke of? How does that come into play? Thanks!

                      Comment

                        #12
                        Re: Samsung PN51D7000FF cycling off and on

                        The firmware is corrupt. Nothing you can do about it since this model is discontinued and no more updates will be available nor parts since they are all out of stock. Like stated above if your tv keeps cycling exactly after 1min 19 seconds you have a bad main.
                        I will let you know if BN94-04402C is a suitable replacement.

                        Comment

                          #13
                          Re: Samsung PN51D7000FF cycling off and on

                          Gotcha. I found the firmware for the TV dated 11/22/12. Thats probably newer than the firmware I have in my TV since I bought it in 2011. I downloaded it, but Im guessing I wont be able to get the firmware to install to the TV since it only stays on for 1min19 secs on average? What would be the consequences if the tv power cycles off during the firmware install?

                          Comment

                            #14
                            Re: Samsung PN51D7000FF cycling off and on

                            That might result in a tv that won't turn on anymore. Might get stuck in just showing a logo or a blinking led.

                            So worst case scenario: Instead of working for 1.5 minutes , it won't work anymore!
                            I only repair Panasonic plasma tv's! Currently owning a TX-P55VT50 and still searching for a ZT60!

                            Comment

                              #15
                              Re: Samsung PN51D7000FF cycling off and on

                              Ok so I received the board today, and here is what I got.
                              The lvds cable connector was broken, but I think I was able to fix it, not sure. The problem is that while the tv turns on and operated properly in terms of internet options and so on, I get green vertical lines on every odd pixel. The menu is not affected by this but does get odd green horizontal lines sometimes. I then played a movie to see what it would do, and sometimes the colors would get really weird in some places. Kind of like in the link below his third picture but not as bad and green/teal instead of red
                              https://www.badcaps.net/forum/showthread.php?t=47843

                              So I don't know if A the board they sent me is bad, B the broken LVDS cable connector that I think I fixed, I actually didn't really fix properly, or C, the board is just plain and simple not compatible. However JayTheSpaz was able to get this board to work for him. I did double check his picture and he does indeed have the same board as I do which is the BN94-04689A. So I am not sure why my set wouldn't work.
                              Last edited by Nick's Tvs; 03-07-2016, 09:37 PM. Reason: Detail

                              Comment

                                #16
                                Re: Samsung PN51D7000FF cycling off and on

                                I have a BN94-04718A from a D6500. Seems to be identical layout etc.
                                PM if interested. Board came out of a wii controller victim.
                                Proud owner of dozens of broken TV's and many,many,many boards.


                                Our website and passion:http://hollenhundshepherds.com/

                                Comment

                                  #17
                                  Re: Samsung PN51D7000FF cycling off and on

                                  Super duper yes!

                                  Comment

                                    #18
                                    Re: Samsung PN51D7000FF cycling off and on

                                    Hmm, thanks for the info Nick'sTVs. Where did you find the alternate board? Are you planning on sending it back and getting a new one since it was defective when you got it? I sent Jaythespaz a PM to see if he could chime in on this thread about his results. Another thing he said on his PM to me, was that he was able to get his TV to power on with the main board disconnected, but I tried that with mine and it would not power on. Dont know how that factors in.

                                    At this point, I have tested all the DC voltages on my power supply and all were within 1 volt DC of what the sticker on the inside said, so Im guessing my power supply is good? IDK.

                                    Comment

                                      #19
                                      Re: Samsung PN51D7000FF cycling off and on

                                      Have you tried bringing up the test pattern? Or did you try to just jump PS-ON to ground and VS-ON to 5volt line?

                                      Comment

                                        #20
                                        Re: Samsung PN51D7000FF cycling off and on

                                        Hi sorry for the late response. Things have been busy. What I had told bp805 via PM was my diagnosis was confirmed by a local shop. They were able to power up the panel without the mainboard connected. In that state the TV no longer power cycled. Unfortunately I am not sure how they accomplished this. The LVDS cable in my TV is still in good shape, so I can't comment on the possible impacts of that for this TV. I ended up getting my board on ebay because, like Nick said, Samsung does not sell them anymore. Get it from a seller who allows returns and you can minimize your risk to the cost of shipping.

                                        Comment

                                        Previous 1 2 3 template Next
                                        Working...
                                        X