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  1. #1
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    820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    Hi,

    I have that board was not turning on at first + no green light.
    Replaced DC-IN board as some diode mode very different from a known working one.
    Still no go.
    I saw a difference in diode mode on F7005 between each side of it. Replaced F7005. Got a quick green light on the charger then off, then green light again and off, etc...

    Decided to use my DC power supply to power the board.
    It tries to turn on, I am getting all the rails (it seems) for a second and then the amperage goes to 0.1 and back 1.5Amp. You can see the fans spinning and slowing down when the amperage goes down then back to normal speed.
    It does that in loop like a quarter fan spin.

    I've checked different the S0 rails and they all show a proper value.

    I can't seem to find what's wrong with it.

    History is : Mac was used with a knock-off charger.
    Board looks fine under the microscope, no sign of corrosion or burnt components.

    I am thinking, I should rework the ISL6259 area. What do you think?

  2. #2
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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    check for leaky gates on q7180 and check all resistor values attached. my money's on bad q7180, but definitely check resistors because those tend to get fucked too with bad dc in. make sure q7010 circuit is good too, d7010 often gets smoked with bad dcin

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    sargfowler (02-13-2018)

  4. #3
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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    You nailed it! After replacing both Q7010 and D7010, it did it.
    I can't tell if it was the transistor or diode but good place to check if this behavior happens again.

    I own you a beer ;-)

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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    7010 gets smoked if a dc in board goes bad. if you use a bad DC in board with an aftermarket PSU or with a snipped msafe end hooked up to the PSU and manage to get the board to power, then you;ll often find q7180 gets burnt out too so I'd still check resistance between the s/d/g and make sure they are right, since the circuit will often still work for a while and make your ppbus, but will act funny and eventually give up the ghost!

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    overshoot (02-14-2018)

  7. #5
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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    Well I am not out of the woods yet.
    Screen is now flickering. It seems to happen when the computer is switching graphics from Intel IRIS to Nvidia GPU.
    Once connected to an external monitor, it is stabilized.

    Could the Mux chip be dead in your opinion?

    EDIT: I just read your answer. I'll have a look at that. Thanks again!
    Last edited by overshoot; 02-14-2018 at 12:40 AM.

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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    Q7180 was replaced. Diode mode on the transistor and the connected resistor measure fine.

    I have ran ASD and it shows an error on the IO5R sensor.

    Here is the video of the flickering by the way: [Only Registered and Activated Users Can See Links. Click Here To Register...]
    This happens when the graphics change from internal to discrete, like when launching Final Cut Pro.

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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    Quote Originally Posted by overshoot [Only Registered and Activated Users Can See Links. Click Here To Register...]
    Well I am not out of the woods yet.
    Screen is now flickering. It seems to happen when the computer is switching graphics from Intel IRIS to Nvidia GPU.
    Once connected to an external monitor, it is stabilized.

    Could the Mux chip be dead in your opinion?

    EDIT: I just read your answer. I'll have a look at that. Thanks again!
    stabilized because it won't switch when external connected.

    Take a close look at these you may have traces bad or damaged 8 x resistors. r8311 - r8318

  10. #8
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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    check those resistors and also check the resistors/filters 8301/2/3, very common to knock one off/loose installing the board; I often get boards back that I do board repair from angry customers that ended up knocking the dang thing off themselves

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    Re: 820-3787 Dead DC-IN Board + F7005 blown. Now quarter fan spinning

    No knock off resistors/filters.
    I did rework the whole area to make sure the connection were proper.
    I've checked for continuity on the filters and everything was fine.

    I did try the system and it worked for a day. At the time the customer came to pick it up, it did happen again... lame! ;-)

    Anyway, happy customer who didn't have to pay for the repair and got a partially working laptop.

    Thanks again for your precious help both!

 

 

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