+ and - flipt on power connection C64 reloaded MK2

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Don't Panic. Please wash hands.

    I am trying to repair a C64 reloaded MK2 but i need to identify a component. The owner swapped the minus and plus on the powerconnector. A diode for protection got shorted that was inbetween the plus and the minus. But there was more damage. I trace the 12v line to a component below the left side of the cartridgeport. This is Q11 with the marking text H7DUQ on it, does any one know which is the correct component for this code?, it looks like a mosfet transistor? But it only measures a diode value in one direction of all 3 pins (checked in all possible combinations).. Normally bad mosfets will shortout as far as i know? the top two pins have a resistor in between of 100k ohms.. this can be a gate connection on one pin? measuring one diode value only after damage can be a PNP transistor?

    Quote from CASBLT

    A diode for protection got shorted that was inbetween the plus and the minus.

    That's D8, a 12V Zener diode that will short anything above 12V or below 0V (reversed). Part# is 1SMB5927BT3G, where the "T3G" at the end means "tape and reel", so not a requirement for your one-off-repair.

    Quote from CASBLT

    This is Q11 with the marking text H7DUQ on it,

    IRLML5203 in SOT23 package.


    Quote from CASBLT

    But it only measures a diode value in one direction of all 3 pins (checked in all possible combinations).. Normally bad mosfets will shortout as far as i know?

    With enough current, you can easily melt a bonding wire and have an open pin.



    Jens