Could I get some help reading this schematic?

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  • orientalsniper
    Badcaps Veteran
    • Apr 2013
    • 459
    • USA

    #1

    Could I get some help reading this schematic?

    First off, PQ2 was shorted. So I replaced it with a new one.

    And now PQ2 does not output any voltages in pins 5-8. I think it's not being activated since pin 4 in both PQ2 and PQ1 are on high (18v).

    So I noticed there's some OCP/OVP protection circuit in page 59. I think the relevant parts are PQ35, PR6. But I don't know how to make sure PQ35 is fine since I never tested its kind before, though it passes diode test I think. Also it has 18V in pins 1,3,4,6.
    Attached Files
    Last edited by orientalsniper; 08-31-2014, 11:51 AM.
  • dj_ricoh
    Badcaps Legend
    • Jan 2013
    • 2073
    • uk

    #2
    Re: Could I get some help reading this schematic?

    so your pq2 and pq1 will open with gate from PU3 pin 4 ACDRV#
    if that chip its broken and does not output that voltage for the mosfet you will not have any power.

    replace pu3 then you will have gate for pq2 and pq1
    Last edited by dj_ricoh; 08-31-2014, 12:06 PM.
    Just cook it! It's already broken.

    Comment

    • orientalsniper
      Badcaps Veteran
      • Apr 2013
      • 459
      • USA

      #3
      Re: Could I get some help reading this schematic?

      I've replaced PU3 with another one from a broken laptop, so I don't know if it's good or bad. But they had the same readings in all pins, the issue is, it takes me 2 weeks to receive any order from Ebay and I would rather confirm everything else is fine.

      Since both these guys changed PU3, I assumed PU3 was fine:
      https://www.badcaps.net/forum/showthread.php?t=36522
      http://www.reballing.es/viewtopic.php?f=22&t=5358

      I have to add if I short PQ2, computer runs fine with power adapter. Battery remains undetected.

      Comment

      • orientalsniper
        Badcaps Veteran
        • Apr 2013
        • 459
        • USA

        #4
        Re: Could I get some help reading this schematic?

        So I had been reading the schematic, would it make sense if I remove PR140 and PR9 and then measure pin4 of PQ1 to check whether ACDRV# is working or not?

        Comment

        • orientalsniper
          Badcaps Veteran
          • Apr 2013
          • 459
          • USA

          #5
          Re: Could I get some help reading this schematic?

          SOLVED:

          Replaced PQ2 and resoldered PU3.

          Comment

          • dj_ricoh
            Badcaps Legend
            • Jan 2013
            • 2073
            • uk

            #6
            Re: Could I get some help reading this schematic?

            perfect!
            for chips like that pu3 I got a microscope to be 100% sure its soldered.
            glad to see that it came on
            Just cook it! It's already broken.

            Comment

            • highpulse
              i hate HP
              • May 2013
              • 1488
              • portugal

              #7
              Re: Could I get some help reading this schematic?

              there is a good technique to solder without using microscope . simpe remove all solder frmo the pins with solder wick in both part board and chip itself , leave on a very small amount on the central pin GND (very small , like the amount of solder of a 0,65 mm ball
              give a bit of hot aair to make the bond on the GND , then apply flux on the 4 sides , and with your iron , gently drop a little big of solder in the iron , and pass slowly on the 4 sides with the iron , all pins will be perfectly soldered , without much need of microscope confirm , just with eye view you can notice if well or not well soldered .

              Comment

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