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Samsung PN50B430 Sparkles After Y-Main Replacment

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    #1

    Samsung PN50B430 Sparkles After Y-Main Replacment

    I manage to work my way through just about any problem these days but this one has me stumped. Picked up said TV from someone used (completely free). Checked it out and it had an obviously blown Y-Main. Buffer chip had a hole in it plus other shorted components. Typically, I wouldn't spend much on this model but the guy said the picture was beautiful until the day it died. Less than a week ago. Anyway, I got a replacement Y-main on ebay and have it installed. TV is functional but has an extreme amount of red and black sparkles. Vs, VA, VSC, are all exactly on spec with the panel. I tried adjusting Vs up and down about 5V and it didn't seem to help at all. Possibly slightly at +5v but definitely not enough to make the TV watchable. Based on what the owner said, it seems to me that it's got to be an adjustment issue. Any opinions on it? I'd certainly like to complete the repair at this point.

    Thanks,

    Aaron
    Attached Files
    Tags: None
    #2
    Re: Samsung PN50B430 Sparkles After Y-Main Replacment

    Looks like a y ramp issue. At the very least slight possibility could be a faulty control board. What's the resistor for y ramp checking?
    Did I leave the soldering iron on?

    Comment

      #3
      Re: Samsung PN50B430 Sparkles After Y-Main Replacment

      Originally posted by freakaftr8 View Post
      Looks like a y ramp issue. At the very least slight possibility could be a faulty control board. What's the resistor for y ramp checking?
      Could you point me in the right direction on where to look for that resistor? I don't think that's something I've checked on other ones. In my experience, raising Vs slightly usually fixes similar issues on these Samsung panels but this one has obviously got a different problem. I won't be able to look at it again til in the morning but I'll certainly follow your guidance on it.

      Emphasis again on the fact that the guy said the picture was perfect until the TV failed with a loud pop just a week ago. The top buffer chip was visibly blown apart so I'd assume that's what he heard. Seems unlikely that it would have damaged anything else. And I suppose there could be something wrong with the replacement I received but I've never seen one produce this issue before.

      Thanks again,

      Aaron
      Last edited by aaronwt6; 02-03-2018, 09:58 PM.

      Comment

        #4
        Re: Samsung PN50B430 Sparkles After Y-Main Replacment

        I'm not to sure I looked over the board this is a board that has the buffers Built-in to the sustain board. Y ramp should ne located off one of those big green resistors It is possible that it could have damaged the Z sustain. What is VE reading on z sustain? Does that match the label on the panel?
        Last edited by freakaftr8; 02-03-2018, 10:58 PM.
        Did I leave the soldering iron on?

        Comment

          #5
          Re: Samsung PN50B430 Sparkles After Y-Main Replacment

          I'll check Ve and let you know. I didn't test that one before. Sure hope the X-main is ok cause at that point I might as well have scrapped the thing. The picture gets much, much worse if the X-Main is unplugged so it's at least doing something.

          Comment

            #6
            Re: Samsung PN50B430 Sparkles After Y-Main Replacment

            You nailed it. Ve is only around 7V. I'm going to look for a repair kit for the X-Main. If I have to spend more than another $20 or so on this TV I'm over it.

            Comment

              #7
              Re: Samsung PN50B430 Sparkles After Y-Main Replacment

              Ok. R4011 on the X-Main is toast. Freakafter8, do you have the value for that resistor? If not, anyone else? Looks like at least a 1-2W, maybe higher. I cannot see the bands to identify due to the damage. It reads completely open. I've checked all the parts included in the kits available and they seek to be ok. I'm hopeful it just needs that resistor.
              Attached Files

              Comment

                #8
                Re: Samsung PN50B430 Sparkles After Y-Main Replacment



                Here's a closeup shot of your board from shopjimmy of the suspect resistor. Hope this helps.
                Attached Files

                Comment

                  #9
                  Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                  Not sure why I didn't think of that. So, it's 82 ohms and I sacrificed one out of a different X-Main. I have 88 volts now for Ve, but drum roll.............The sparkles persist. And what's really weird, I can't tell a difference from when Ve was only 6-7V. So, think there's got to still be an issue on the X-main. If anyone has more things for me to test, I'm all ears.

                  Thanks again guys!

                  Aaron

                  Comment

                    #10
                    Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                    There are repair kits that contain (4) RJH3044 IGBTs and (4) 10 ohm resistors but nothing in the area of those seems to be shorted and the resistors check out exactly at 10 ohms.

                    Comment

                      #11
                      Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                      Just a thought. I know enough about this to be dangerous as I am learning everyday but can you access the test patterns, maybe through the menu, and see if you still have the defects. Maybe could be the main board with the video inputs that may be contributing to the issue? I’m probably way off the mark. Had one with a lightning strike that had a similar effect and ended up being a main board issue.

                      Comment

                        #12
                        Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                        I haven't tried that yet but I'll give it a shot when I get back home. Seems strange that fixing that bad resistor made no noticeable difference. I was really expecting a clear picture after swapping that.

                        Comment

                          #13
                          Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                          I would have thought the same what little know. Good luck

                          Comment

                            #14
                            Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                            Tried the test patters. Definitely no change. Sparkles were still present. Also tried a different logic board which also didn't help. Rechecked all my voltages. All are dead on per the panel setting. I tried adjusting Vs up a bit from the 210 label which seemed to make a marginal improvement. I only went up to 212.5 though out of fear of damaging something. Anyone know what the max I should try, even if it's just to see if it improves?

                            I do believe that there are fewer sparkles now with that resistor repaired on the X-Main but its still not acceptable for viewing.

                            Thanks again,

                            Aaron
                            Last edited by aaronwt6; 02-04-2018, 04:16 PM.

                            Comment

                              #15
                              Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                              There are 3 other pots on the Y-Main that I'm not familiar with aside from VSC (which is dead on). I'm wondering if it could be one of those but don't want to blindly tinker with anything.

                              Comment

                                #16
                                Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                                Sorry was out at the park all day with my kids. If you found a burn resistor and replaced it now your VE is back up, That's does not necessarily mean that VE is reaching the panel you would want to check at the output ribbons of the X sus To make sure that there's no open components on the output.

                                The other parts of a Y main are ramp up, ramp down, -vy Which could equally be a problem. However given the design of this board I doubt that you will find a problem from a shorted buffer sense this board has not experienced this before.

                                I would be looking at more issues with the X sustain. I'm surly certain that the short a buffer traveled through the panel in damaged the X.

                                You will probably signed other components on the output of the exe like other open resistors or open fuses.
                                Did I leave the soldering iron on?

                                Comment

                                  #17
                                  Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                                  Well, I have a positive update. After checking over everything I could think of on the X-Main without finding any additional issues, I went back to the idea of tweaking voltages again with the pots. This time with more of the attitude of it either works or it gets tossed. With the following readings, I have a beautiful picture on it and they seem to me to be 'close enough' to the originals to not mess anything up. Any opinions on the settings are certainly welcome.

                                  Ve 90V
                                  Vs 214V
                                  VSC -195V
                                  Va remains at 55V
                                  Attached Files

                                  Comment

                                    #18
                                    Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                                    Those numbers I relatively close to the original voltage ratings. You could be compensating for an aged panel Which would make sense.

                                    Nice job!
                                    Did I leave the soldering iron on?

                                    Comment

                                      #19
                                      Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                                      Originally posted by freakaftr8 View Post
                                      Those numbers I relatively close to the original voltage ratings. You could be compensating for an aged panel Which would make sense.

                                      Nice job!
                                      Thanks! I feel dumb for not noticing that blown resistor on the X-Main. In the end, seems that was the only real issue with it. I was on the verge of just scraping the TV. Glad I decided to continue to tinker with it.

                                      Comment

                                        #20
                                        Re: Samsung PN50B430 Sparkles After Y-Main Replacment

                                        Congrats! Nice fix

                                        Comment

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