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820-2530 ppbus .19 volts always stays green

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  • #16
    Any diode should work there; not dificult to find one.
    It should work with jumper too.

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    • #17
      I did put a big fat diode on there. Pin 2 is not shorted. I have a short on pin 17.
      Last edited by shanenin; 02-13-2019, 05:59 PM.

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      • #18
        So you have a short on PPBUS_G3H.
        Remove F7000 and see which side the short remains.

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        • #19
          I am embarrassed. I am not sure what I did, but 17 is not shorted :-( Sorry. I think I may have read M(ohm) as plain ohms

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          • #20
            OK, post then voltage at mentioned pins of U7000; after D7010 was changed.

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            • #21
              I do have a good ppbus of 12.61. I did before for a few minutes last time, but it did not last and d7010 burned out.

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              • #22
                So D7010 is burnt again???
                Really strange, as you got correct PPBUS_G3H.
                Change C7010 too...

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                • #23
                  I am sorry for being unclear. My oversized D7010 is still good and I still have a good ppbus. I was trying to say, whatever caused d7010 to burn out twice, will it happen a third time? What has changed?

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                  • #24
                    D7010 was burnt because of U7000, pretty sure.
                    Change C7010 just in case...

                    Is the board working now?

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                    • #25
                      now I lost ppbus, or it is .4 volts :-( This time d7010 is still good. I wonder if I shorted something on u7000 by checking voltages on some of the other pins(just curious). I will get more info later for you. Thanks for all of the help.

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                      • #26
                        I now have 22.5 ohm between 17 and 18 and still have 20.4 ohm between 27 and 28. May I ask what you were checking for when you asked for these?

                        these are the new voltages on the isl pins:
                        2 18.5v
                        3 4.4v
                        19 0.2v
                        20 0.2v
                        12 3.4v
                        1 18.6v
                        14,9,15 all have 0v

                        I also have short on 19 and 20, is that the issue?





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                        • #27
                          "19 0.2v
                          20 0.2v
                          ------------
                          I also have short on 19 and 20, is that the issue?"
                          For sure...
                          If both pins have short to ground, bad ISL6259.
                          When remove it, check for any short to ground before solder another one.
                          Change R7040, probably burnt now.

                          "now have 22.5 ohm between 17 and 18 and still have 20.4 ohm between 27 and 28"
                          All correct there.

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                          • #28
                            after pulling off the ISL, the only shorts are 6 and 22, but I think they are both grounds and normal. I am hesitant to put another one on as something is frying it. The board came to me with a bad d7010. I replaced it and I had ppbus for a few minutes then d7010 fried again. I then replaced that diode with a stronger(I am assuming) one, then my ISL fried. I am guessing whatever was frying the d7010 was what fried the ISL since this time the d7010 did not act as a fuse.

                            I do have the original ISL I pulled. I suspect it may have been good, since d7010 probably protected it. Before I put it back on, what might be damaging the circuit?

                            this is an isl 6258, I noticed Rossman does not sell this one and I am out of new donors

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                            • #29
                              Is true, that is ISL6258.
                              D7010 gets burnt because of U7000, not viceversa.

                              "2 18.5v"
                              A bit higher the input voltage.
                              Are you using bench power supply, or fake chinese charger?
                              16V should be normal voltage for original 60W charger.
                              However, original 85W charger shouldn't burn anything...

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                              • #30
                                It is a cheap one I have used for years. I will throw it away. I have only been buying genuine ones since I started following Rossman videos. Assuming the charger is not what fried it, could other things be doing it?
                                Last edited by shanenin; 02-18-2019, 10:30 PM.

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