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    #1

    Samsung 305T Plus issues

    To the mods: I have seen the 305T thread but because it is quite a different error, and the model is different I started a new thread. Feel free to merge if you prefer.

    I own a used Samsung 305T Plus, for several years it worked ok, now it has decided the world should end in 2012. Since 30" monitors are now all crappy IPS (I loathe the shimmering effect) I really would like to fix it. In another thread they're talking about reflowing the boards, but the service manual of the 305T Plus shows different boards and since the distortions are quite different from the green haze that come up with Google, I'd like your input.

    I include a picture that shows the issue (without the flicker of course ) The top third of the screen shows the bottom part again, in a transparent flickering way, and added are flickering thin multicolored lines. The lines happen on bad cables too so I replaced mine, to no avail. Also tried different gfx card, no joy.

    The service manual shows only two boards. The signal input & processing board and the powersupply. Or should one also disassemble the display unit itself? I haven't opened it up yet, I'm waiting for Samsung service to call back and see what they charge for an estimate. Opening the case is easy, but I don't feel confident opening the display unit itself, should dust get between the glass plates.
    Attached Files
    Tags: None
    #2
    Re: Samsung 305T Plus issues

    Pictures of the boards in the monitor would be helpful. Opening the LCD panel itself should not be necessary - this is probably a fault in the tcon. It is possible it is a failure in the signal board or the LCD panel. I would suspect the tcon; if it is the LCD panel it is unrepairable.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

    Comment

      #3
      Re: Samsung 305T Plus issues

      ok, I'll see when I can make those pics. The display unit should be OK, in the BIOS screen only the flickering lines show up, and with no signal the monitor flashes sequences of full screen colors without distortions as it should

      Comment

        #4
        Re: Samsung 305T Plus issues

        OK, here are the pictures. Turns out there are 4 boards accessible, though 2 of them seem part of the display unit. The top board with Altera is there, just like on the 305T non Plus. Strange the service manual does not mention them. Since I don't know what each of these boards do exactly, I named them for their position or obvious role (power, input).

        None of the caps are bulged or bloated, they look outwardly fine (and I do know how bad caps can look - thrown out dozens of Dell SX PCs or MSI mainboards at work with caps foaming at the mouth )
        Attached Files

        Comment

          #5
          Re: Samsung 305T Plus issues

          The first board is what I refer to as the signal board, others call it the logic board. The second is the inverter. The third and fourth are bottom and top views of the power supply, the last two are the tcon.

          There are several auctions on eBay selling replacement tcons as a solution to the problem you describe. There are also several auctions selling capacitor kits as a solution to the problem. Given that you can recap the power supply and the signal card and the inverter for a small fraction of the cost of a tcon, recapping might not be a bad idea.

          PlainBill
          For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

          Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

          Comment

            #6
            Re: Samsung 305T Plus issues

            Thanks Bill! Will recapping solve the issue or just improve quality and lifespan (so I still need to get a replacement TCon; found a Dutch dealer selling it at 215 EUR, not cheap)

            Would reflowing the TCon help, or do you think some component is actually broken?

            Comment

              #7
              Re: Samsung 305T Plus issues

              Originally posted by KuroNeko View Post
              Thanks Bill! Will recapping solve the issue or just improve quality and lifespan (so I still need to get a replacement TCon; found a Dutch dealer selling it at 215 EUR, not cheap)

              Would reflowing the TCon help, or do you think some component is actually broken?
              Here's my $.02 worth. It could be any of the three - bad caps on the power supply, bad signal card, bad tcon. In my opinion, it is probably not the signal cards, and nobody is selling signal cards as a fix for the problem. That leaves a complete recap at $20 or a used tcon at $185. Since the recap is always a good idea on Samsung monitors, I'd start with that. If you get lucky, great! if not, there is always buying the tcon.

              I have now personal experience reflowing the solder on BGA chips, but it makes sense that it should be done in the proper manner - first remove the chip, have it reballed with 63/37 solder, and reinstall. I have no idea what that would cost.

              Assuming the most expensive approach is taken - a new tcon and recapping - you have invested less than $300 into a monitor worth twice that.

              PlainBill
              Last edited by PlainBill; 01-08-2012, 08:57 AM.
              For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

              Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

              Comment

                #8
                Re: Samsung 305T Plus issues

                I have not had time to work on the monitor in the past weeks, but with some free time coming up next month, I'm getting the necessary stuff together.

                I also tested a bit more with the monitor and noticed it will work fine at resolutions up to 1280x800. Above those the picture errors occur.

                Now, this monitor does not natively support any resolution apart from 1280x800 and 2560x1600. Anything inbetween, including 1920x1200 must be scaled by the graphics chip. So I do not know if resolutions above 1280x800 are already dual link.

                So my question is, can such an error, which only occurs at higher resolutions still be caused by the Altera's "bad soldering connections", solved by reflowing the board? I'm no electronics expert, but the dependency of the error occuring on signal frequency sounds to me more like a bad caps issue?

                Your thoughts?

                Comment

                  #9
                  Re: Samsung 305T Plus issues

                  Originally posted by KuroNeko View Post
                  I have not had time to work on the monitor in the past weeks, but with some free time coming up next month, I'm getting the necessary stuff together.

                  I also tested a bit more with the monitor and noticed it will work fine at resolutions up to 1280x800. Above those the picture errors occur.

                  Now, this monitor does not natively support any resolution apart from 1280x800 and 2560x1600. Anything inbetween, including 1920x1200 must be scaled by the graphics chip. So I do not know if resolutions above 1280x800 are already dual link.

                  So my question is, can such an error, which only occurs at higher resolutions still be caused by the Altera's "bad soldering connections", solved by reflowing the board? I'm no electronics expert, but the dependency of the error occuring on signal frequency sounds to me more like a bad caps issue?

                  Your thoughts?
                  I guess the question is that when you go to the higher resolutions does the problem appear immediately or does it take time to appear? If it takes time, then it could mean that the Altera chip is heating up. You could try using a fan to blow air on the chip to see if it lengthens the time before you see the problem occur.

                  Comment

                    #10
                    Re: Samsung 305T Plus issues

                    OT: what's with the workgroup name in the first pic? :O

                    But yeah.. seeing that it uses the infamous altera chip, that would be my prime suspect. Try heating it up a bit with a hairdryer and cooling it with a fan to see if the problem shows up or goes away.

                    Comment

                      #11
                      Re: Samsung 305T Plus issues

                      Originally posted by KuroNeko View Post
                      I also tested a bit more with the monitor and noticed it will work fine at resolutions up to 1280x800. Above those the picture errors occur.
                      It's a bad dual link DVI cable. If a single link DVI cable works up to 1920x1200 then buy dual link cables until you get a good one. The first two dual link cables I bought showed all manner of fuzzies and flashing blank screens.
                      sig files are for morons

                      Comment

                        #12
                        Re: Samsung 305T Plus issues

                        Thanks for all the replies guys! I'll provide a bit more detail to answer your comments:

                        - it happens immediately. If I switch back down to 1280x800, it immediately disappears. So no overheating of the Altera (yet)

                        - I have tried several dual link cables, same result. Single link cables give no picture at all, not even at 1280x800.

                        I just ordered a new Tcon board. If the seller can deliver (not in stock) that leaves me with the old one to 'experiment' (providing replacing the board solves the problem). If I can find a decent new soldering/desoldering set for an affordable price I'll try recapping too, my old one bit the dust.

                        @Scenic: hello neighbour (I'm in BE)! You mean "Das neue Reich"? I can imagine someone from Germany frowning on this. But it has nothing to do with Hitler's bunch, I assure you. Google for "Legend of Galactic Heroes", and you'll find out more (lots of info on Wikipedia too). It's a scifi drama about politics and war between two nations. One an empire, another a democracy, where it is not always clear which is which, highly recommendable, especially in the current political situation in the west.

                        Comment

                          #13
                          Re: Samsung 305T Plus issues

                          Hey all,

                          I poked in here a few months ago when my monitor started acting up, and am really impressed with how much info is here and how willing folks are to help!

                          I'm having almost this exact same problem on my 4 year old Samsung 305T (The screenshot KuroNeko posted is identical to what I'm seeing, but I get this behavior at all resolutions), and figured I'd attempt a self repair.

                          So far I've taken it apart and checked the voltages and some of them are a bit off. For example, the 24V output from the SMPS comes out to 24.48V. The 5.4V comes out at 5.35V. The 3.3V (POWER_EN) on the logic board comes out at 3.05V. Only the 6V standby comes out dead on (well, 5.99V). While I'll probably end up recapping the SMPS anyway, I was wondering if these values are within the "normal" tolerance range for these sort of electronics, or is this an indication of a problem? What would be considered an acceptable voltage variance?

                          The voltage values are steady, even with the monitor powered up and running, and my multimeter is a pretty decent model so I believe I can trust the data. The AC power comes in exactly at 120V and is behind a UPS/Power conditioner.

                          I've included some photos of the SMPS, but as with KuroNeko's boards, the caps on it appear in pretty good shape. It's interesting that they have a mix of CapXon and Rubycon caps. Since Rubycon is on the "good caps" list in the FAQ, if I were to swap the caps on this, would you recommend just swapping the CapXon caps, or do them all?

                          I've also included the schematics (305T[13].pdf) and some relevant pages of the troubleshooting guide Samsung provides, in case anyone having the same problem doesn't have them.

                          KuroNeko; I'd be curious to know if swapping your T-Con board solved your problem, so please post when you're done! In fact, if you're going to do that soon I may just wait on the re-cap and see what you find out. ;-)

                          Oh, one last question; The troubleshooting guide talks about checking the waveforms (albeit for their no-power scenario), but I haven't seen that talked about a lot here. Is this generally not a helpful step or does this provide useful information? I don't have an oscilloscope, but could probably borrow one if it would allow me to isolate the problem.

                          Cheers,
                          Kevin
                          Attached Files
                          Last edited by kklemmick; 02-28-2012, 02:05 AM.

                          Comment

                            #14
                            Re: Samsung 305T Plus issues

                            Originally posted by kklemmick View Post
                            The 3.3V (POWER_EN) on the logic board comes out at 3.05V. Only the 6V standby comes out dead on (well, 5.99V). While I'll probably end up recapping the SMPS anyway, I was wondering if these values are within the "normal" tolerance range for these sort of electronics, or is this an indication of a problem? What would be considered an acceptable voltage variance?
                            The POWER_EN is a bit low, but assuming it is the power on signal from the main board, then it is working because all your secondary voltages are present.

                            On most lcd power supplies, the secondary voltages are usually not regulated so your stable voltages are okay even though they are off a bit. The one exception might be the 5V (or 6V in this case) standby.
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                            Comment

                              #15
                              Re: Samsung 305T Plus issues

                              Good timing, I just received confirmation from the Dutch repair parts shop (official Samsung parts dealer) that my order has been shipped. I should have it by next weekend so I'll try and fix it then and keep you informed

                              Comment

                                #16
                                Re: Samsung 305T Plus issues

                                I have interesting news to report..

                                I didn't recap, but because I'm extremely impatient I decided to try reflowing the Altera chip on the T-Con board, as I've seen both here and elsewhere that this is the most common thing to go wrong with those boards and doesn't require waiting on parts.. Well, this has fixed the monitor!

                                To be fair, I don't know how long it will last, but if I see the problem again I'll add a fan or something to try and keep it cool.

                                I basically did what is described here:
                                http://hardforum.com/showthread.php?t=1527751

                                Except in my case I used a soldering iron and heated up a quarter (coin) sitting on the back of the chip. I added a small amount of flux paste around the edges of the chip (just below the aluminum) until the flux was entirely sucked in and then let it cool down. I didn't smell the tell-tail solder melting smell, so I probably didn't heat it up as much as others have said they needed to.

                                The nice thing about this repair: Zero cost! (except for my time, which was about 30 mins).

                                @KuroNeko: I'd suggest trying this solution - particularly if you've got a replacement board on the way. It doesn't actually require removing the chip. Just heat it up in place and let some flux flow in. If it works, resell the board.. ;-)

                                Again, word of caution: I don't know how long this will last.. But if it breaks down again, I'll be sure to post here so folks will know.

                                Cheers,
                                Kevin

                                Comment

                                  #17
                                  Re: Samsung 305T Plus issues

                                  Slap on a heatsink on that bugger and you should be good for an year or so. Use thermal adhesive to secure the heatsink to the chip, or if you're cheap n nasty like me, apply a blob of regular thermal paste in the middle of the chip and a dab of super glue in each corner, then press the heatsink on and hold it for a minute or so till the glue fully sets.
                                  Originally posted by PeteS in CA
                                  Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                                  A working TV? How boring!

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                                    #18
                                    Re: Samsung 305T Plus issues

                                    Originally posted by Th3_uN1Qu3 View Post
                                    Slap on a heatsink on that bugger and you should be good for an year or so. Use thermal adhesive to secure the heatsink to the chip, or if you're cheap n nasty like me, apply a blob of regular thermal paste in the middle of the chip and a dab of super glue in each corner, then press the heatsink on and hold it for a minute or so till the glue fully sets.

                                    I didn't think super glue could withstand the heat. Good info to know. Also, Severach did a fan/heatsink mod to his Gateway monitor, which uses the same board. May not work for the Samsung, but his photos will definitely provide some useful ideas:

                                    https://www.badcaps.net/forum/showth...highlight=305T

                                    Comment

                                      #19
                                      Re: Samsung 305T Plus issues

                                      I didn't think super glue could withstand the heat. Good info to know. Also, Severach did a fan/heatsink mod to his Gateway monitor, which uses the same board. May not work for the Samsung, but his photos will definitely provide some useful ideas:
                                      Indeed! Turns out I had a 12V 120mm Antec LED fan lying around in my spare parts drawer, so I threw it on by soldering the included power cable to the 18V output. It doesn't fit under the back cover though (about 1.5 inches to tall), but I was planning on leaving that off for now anyway. On the plus side it has the advantage of snapping in nicely with a single peg. It has 3 speeds and at the lowest I don't hear it at all and it has more than enough airflow to keep the metal T-Con cover cool to the touch after 2 hours of load I've thrown at it.

                                      Next time I'm at Fry's I'll pick up an 80mm inch fan and see if that will fit under the cover. It certainly won't cover as many of the holes, but considering this thing went 4 years with no cooling at all, I can't see why it would need anything more than a little airflow to keep it below the heat threshold.
                                      Attached Files

                                      Comment

                                        #20
                                        Re: Samsung 305T Plus issues

                                        A little update on my part: replaced Tcon, problem fixed. I'll use the old board to experiment on reflowing the Altera with a cheap hotair soldering station

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