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Samsung LE32M86BD continuous power cycle

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    #21
    Re: Samsung LE32M86BD continuous power cycle

    This board only has two small BGAs on it: the Samsung DNIe engine, and a Micronas device. The Samsung relied just on the shield for cooling, the Micronas had a small heatsink attached with gooey thermal adhesive. There's another larger chip under a heatsink but that's a QFP package.

    I decided to reflow the Micronas. The board is cooling now, we'll see what the outcome is. Edit: Same thing. It's marked as "OPTION" in the service manual anyway... On the other hand, i pressed with my finger on the DNIe engine (didn't bother to put the shield back on the board), and it stayed on after just a minute of being powered up. Garbled screen tho. So, the DNIe engine BGA is up next. Funny thing is - the DNIe chip barely gives out any heat.

    Edit 2: Finished with the DNIe too. Powered up first time, but stupor: Garbled screen. Heating up the board while it is working and power cycling the set afterwards brings the picture nice and clean. So the power issue and the garbled screen issue aren't one and the same. Grr. I'll now heat the devices one by one using a smaller nozzle, and see which one is buggy. The only one left is the big TQFP... Or maybe that crystal oscillator on the board is bad... We'll see.

    Edit 3: Not entirely sure as i got pissed and removed the smaller nozzle and heated the whole board, but it went like this:
    • TQFP to 80 deg C? Garbled.
    • Micronas to 80 deg C? Garbled.
    • DNIe to 80 deg C? Garbled.
    • Whole area, including TQFP, Micronas and SMD electrolytic capacitors to 80 deg C? Running in spec...


    Stupid capacitors. Gonna pull them one by one and check for ESR.
    Last edited by Th3_uN1Qu3; 09-04-2012, 06:12 PM.
    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!

    Comment

      #22
      Re: Samsung LE32M86BD continuous power cycle

      Bad SMD Samwha/Samyoung too? Samsung, you disappoint!

      The "Samsung DNIe" is likely just the main image processor SoC (it's also going to have the main processor on it) so very important for the image. I doubt they dedicate an entire ASIC to silly contrast/brightness/sharpness adjustments... On the LE32N73 it had the DNIe processor, as well as a main MICOM and sub MICOM. Sub MICOM was responsible for power up, error detection, IR, LED. Main MICOM communicated with DNIe to add OSD etc., it handled video switching and sync detection for VGA. Not sure why the sync detection was done on the main MICOM though.
      Last edited by tom66; 09-05-2012, 02:25 AM.
      Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
      For service manual, schematic, boardview (board view), datasheet, cad - use our search.

      Comment

        #23
        Re: Samsung LE32M86BD continuous power cycle

        Originally posted by tom66 View Post
        Bad SMD Samwha/Samyoung too? Samsung, you disappoint!
        ... Nope. Caps tested good, replaced and still the same. Either garbled, or just entirely blank screen on power up (like the Tcon is left unconnected).

        I found the board for sale for $45. Messaged the owner about it.
        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!

        Comment

          #24
          Re: Samsung LE32M86BD continuous power cycle

          It may or may not be the same problem, I'm just throwing it out there.
          I just had a different Samsung LN-T375 and had the same symptom and ended up being the panel. When I disconnected on of the four ribbons going to the panel the TV powered up. Before that was just power cycling.
          Found blown chip on the T-con, Tom66 said that it's the gamma chip.

          Comment

            #25
            Re: Samsung LE32M86BD continuous power cycle

            Since this one did the same when i unplugged the Tcon, before reflowing the BGAs on the sub board, we can rule that out. It's definitely the sub board here.
            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!

            Comment

              #26
              Re: Samsung LE32M86BD continuous power cycle

              Got a message from the owner, he said he doesn't want to buy the board, because the board isn't for sale locally and can't be tested before buying.

              I'll offer him $60 for the whole TV as-is and buy the board myself. I think he'll accept. I have a firm offer of $170 for this set already, so that would be $65 profit which isn't bad.
              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!

              Comment

                #27
                Re: Samsung LE32M86BD continuous power cycle

                I hope you can fix it. It would be interesting to see if it is that board at fault, I hope it is. Your first LCD TV repair? Once you start... you can't stop!
                Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                Comment

                  #28
                  Re: Samsung LE32M86BD continuous power cycle

                  Well, he doesn't wanna sell it. Or rather, his father doesn't, it's his TV. Put it back together. The good news is that it works fine after a while just like before, so i won't have any "you broke it" comments.

                  Edit: Entered factory mode. Panel on time is 17450 hrs.
                  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!

                  Comment

                    #29
                    Re: Samsung LE32M86BD continuous power cycle

                    On the T3 board, French-**** sign on top, top right on open TV set, model LE32M86BD Zou have electrolytic 1uF, only one, on edge, which You will measure that is OK.
                    - CHANGE IT! And try power on.
                    p.s. It is crucial for oscilator and power 3.3V which returns signal to main MB.
                    Probably going on breakthrough in mS.

                    Comment

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