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Samsung UN60EH6000 Tries to come on, but stops

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    #61
    Think it should be inverter fault

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      #62
      Re: Samsung UN60EH6000 Tries to come on, but stops

      if you replace the isl9860 make sure there is enough solder on the center pad.
      the 3 i have replaced did not.
      this may also be the cause of the 5 minute shutdown.
      the main path for heat to get out of the chip is through the pad to the boards copper ground plane.adding the sili pads to the chip is not good enough.

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        #63
        Re: Samsung UN60EH6000 Tries to come on, but stops

        Hi, the ISL9860 (IC7100) i think is almost surely bad, after replacement of it one must replace also the power mosfet around it (Q7101) and some diodes (D7106-7 at least) or only the chip and after try heating them all at turn to see which one shortens the working period. And also kc8adu advice is good, ther can be a thermal protection, one can warm up it a bit with the soldering iron before switching on and see the behaviour..
        Last edited by Davi.p; 12-21-2017, 06:43 AM.

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          #64
          Re: Samsung UN60EH6000 Tries to come on, but stops

          Thanks for the input guys.
          So, today I went ahead and replaced the same IC on two more 00628C boards that I had defective with same issue, no picture only backlight.
          One of them is giving me the same problem, picture cuts off after 15 min and the other is working fine, 2hrs so far.

          I noticed that the ones that cut picture off, the big IC's in the middle of the board, they get extremely hot.

          Inputs? Should mosfets and diodes cause this?

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            #65
            Re: Samsung UN60EH6000 Tries to come on, but stops

            Louis see the post #53 , test the point R that i think is the dc-dc regulator that feeds power to the processor (vcore) even if i can't judge if is a correct value or have to be a little more, example 1,2v, but 1v is almost typical...

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              #66
              Re: Samsung UN60EH6000 Tries to come on, but stops

              Hi Davi. It’s 1V

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                #67
                Re: Samsung UN60EH6000 Tries to come on, but stops

                Or it's drawing to much current due to a intermittent short on the panel...

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                  #68
                  Re: Samsung UN60EH6000 Tries to come on, but stops

                  All three boards measured 1V. One of this board seems to be doing fine. Tv is still playing. Going for two days of testing now.

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                    #69
                    Re: Samsung UN60EH6000 Tries to come on, but stops

                    I got the new chip installed along with two new caps. TV still does the same thing when I turn it on.

                    Before, the two caps measured shorted between them, but they are open now even with the new IC in place.


                    @davi.P
                    The points that I measured before for you... can you tell me what they "should" be reading? I am getting some different readings now on points N-T (post #53), but I don't know if what I am getting is good or bad.

                    Thanks,
                    Kirk

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                      #70
                      Re: Samsung UN60EH6000 Tries to come on, but stops

                      T= IC Supply pins= 12v, N= Switch-In = around 15v, if N not=15 then test the point O, if i understand if N not=15v then O not=15v, unfortunately the complete datasheet is by request, i have requested another D.S. to Texas Ins. for example, as a "hobbyst repairer" , they provide it to me.. i don't know what command that switch..
                      For info:

                      https://www.intersil.com/content/dam...9/isl98602.jpg
                      Last edited by Davi.p; 12-24-2017, 09:18 AM.

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                        #71
                        Re: Samsung UN60EH6000 Tries to come on, but stops

                        Yea. My "O" is not that value, so I am at lost as what to do next. I double checked that the ic is seated good and there are no bridged points. I have a good magnifing glass, but those points are really tough to see. Maybe I need to get a higher power glass.

                        Might be time to be trying to find a replacement board.

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                          #72
                          Re: Samsung UN60EH6000 Tries to come on, but stops

                          So which readings you have for points N,T,O?

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                            #73
                            Re: Samsung UN60EH6000 Tries to come on, but stops

                            N=12.7v, T=12.7v, O=18mV

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                              #74
                              Re: Samsung UN60EH6000 Tries to come on, but stops

                              Hi, the ISL is not switching a the output (pin40,39 AVDD/SWOUT) must be 15v, if O (pin38 of ISL) is 12v is because maybe an output circuit shorted to GND, so measure the N point to GND in ohm, if you see few ohms then something on the panel is sh.c., or maybe the new ISL chip is already shorted (measure in diode test between pin 36-37 and GND, if few millivolts=shorted).
                              Last edited by Davi.p; 12-28-2017, 01:06 PM.

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                                #75
                                Re: Samsung UN60EH6000 Tries to come on, but stops

                                Originally posted by Davi.p View Post
                                Hi, the ISL is not switching a the output (pin40,39 AVDD/SWOUT) must be 15v, if O (pin38 of ISL) is 12v is because maybe an output circuit shorted to GND, so measure the N point to GND in ohm, if you see few ohms then something on the panel is sh.c., or maybe the new ISL chip is already shorted (measure in diode test between pin 36-37 and GND, if few millivolts=shorted).
                                Tested point "N" to GRD its open, not shorted. I had 12.7V here.... but on the output side (pin 39 or point "O"), there is only 18 MILLI-volts. I agree that this needs to be somewhere between 9.5 to 15 Volts. Ohm tested point "O" back to ground and its open.

                                I looked at the schematic of the ISL9860 and found each point that should be going back to ground. Checking each point back to ground, I get this:
                                Pin 24 (VDC) = 400k ohms
                                Pin 28 (Phase1) = 504
                                Pin 26 (PGND2) = 0.7
                                Pin 7 (PGND1) = 0.5
                                Pin 33 (PGND3) = .5
                                Pin 34 (PGND4) = .5
                                Pin 12 (GHC) = 100k
                                Pin 11 (GHON) = 9.7k


                                I pulled the chip back off the board and tested from each trace around where the ISL9860 sits back to ground to see if anything was closed that shouldn't be. The following pins show shorted to ground, Pin 7,26,33,34. Which makes sense with the schematic of the chip.

                                I wanted to see if the chip itself was shorted, but with the chip off the board, I checked 36 to GND and 37 to GRD. This is open. GND being the center heat sink of the chip.

                                Any other ideas? Right now the chip is not on the board.

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                                  #76
                                  Re: Samsung UN60EH6000 Tries to come on, but stops

                                  Sorry, many errors by me in the last post... both digitation and not.. not a good idea for me to remove the chip again so soon. Since datasheet is not complete, i assumed PVin1-2 was the chip supply pins, but i can be wrong, maybe are only the input of the BUCK1, so remount the chip and check SUPN-SUPP pins (5,9), maybe you can test them in volt also before remount the chip, the better is that you contact intersil (www.intersil.com) and ask him for the datasheet, tell him that you are an hobbyst repairer.

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                                    #77
                                    Re: Samsung UN60EH6000 Tries to come on, but stops

                                    I just ordered a replacment board and got that installed. TV works great now, so it is definitely a problem with the T-Con board. The board that I replaced this with is a BN95-00944B (BN97-07663A). This board doesn't have the same ISL9860 chip on it. I was hoping it did, that way I could check some voltages and ohms on the working board and compare that to the non-working board and find the problem.

                                    I may try again to replace the ISL9860 on my original board and see if it works. Since I could not find anything that stands out as being the problem, it might just be my soldering job.

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