I haven't been able to find a schematic or board view for one of these out in the wild. I had one come in with a no charge/no boot issue.
It Uses two pairs of Source to Source Mosfets after the power jack to prevent back flow from battery or PSU after the power jack.
The drain on the board feed side of the Mosfets measures a near dead short to ground. I attempted a voltage injection there it draws about 1.4A at 1V absolutely nothing heats up on the thermal camera.
It draws 1.86A injecting directly to ground.
Is this just the way it is when these ultra low impedance Mosfets fail? So little power is dissipated across the failed junction that it doesn't heat up at all?
I saw something similar happen to a 2020 ASUS Zephyrus I was working on where the buck converter fets. shorted.
Is there an easy way to detect those failed parts so one doesn't need to desolder every power mosfet on the board until its located?
It Uses two pairs of Source to Source Mosfets after the power jack to prevent back flow from battery or PSU after the power jack.
The drain on the board feed side of the Mosfets measures a near dead short to ground. I attempted a voltage injection there it draws about 1.4A at 1V absolutely nothing heats up on the thermal camera.
It draws 1.86A injecting directly to ground.
Is this just the way it is when these ultra low impedance Mosfets fail? So little power is dissipated across the failed junction that it doesn't heat up at all?
I saw something similar happen to a 2020 ASUS Zephyrus I was working on where the buck converter fets. shorted.
Is there an easy way to detect those failed parts so one doesn't need to desolder every power mosfet on the board until its located?