jeffrimko

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  • Update on this, I think the Skylake PCH chip may have failed. This is based on: * A number of shorted power supply lines run directly to the PCH, e.g. +1.0VALW. * When supplying 1V to one of these shorted power supply lines and limiting the current to a few amps, the PCH is the only component that seems to get warm. So…
  • Thinking about it more, it's strange that with so many shorts to GND that there doesn't appear to be any current drawn from the bench power supply. I even tried ramping up the voltage but never seen any current draw register. Maybe there is short circuit protection somewhere that is active. I will try tracing from the…
  • Haven't found the problem yet. Been using a multimeter in beep mode and checking around the motherboard for shorts to GND. There are a lot. Focusing only on the large inductors, there are seven that are shorted to GND: PL809, PL807, PL806, PL7201, PL1301, PL602, PL402. Unfortunately, I don't have good soldering equipment…
  • Was able to find a schematic for this motherboard. After reviewing it a bit, don't think that previously mentioned MOSFET is the issue. Going to debug a bit more later today. Will report back if I find anything.
  • Haven't found a visibly damaged capacitor yet like in the video. Checked a few MOSFETs and found one that might be an issue, it has 19V on the drain and 0.2V on the source and gate. Checked this with the CMOS battery installed to make sure that didn't factor into the MOSFET turning on. The designator is PQ302, haven't…
  • Thank you very much for finding that video! It's useful to see how to remove the motherboard, I haven't tried removing it yet because wasn't sure if the heatsinks also had to be removed. I will take a closer look later today to see if I can find a damaged component.
  • Tried leaving the battery disconnected then connected the power supply but no LEDs turn on and the power button is unresponsive. Unfortunately I don't have any other RAM to test with. Guessing they are not the issue though since the LEDs would likely still come on even if the RAM is removed. Guessing something is up with…
  • Ah okay, just checked and the model I have does not have that extra switch. I see the empty footprint where it would be placed though. Here's a picture of the motherboard, a lot of stuff is disconnected while I investigate and I removed the tape from the SW2 switch:
  • Think the rightmost switch in the picture is the case removal switch (the one just below the memory). That's the one I have taped down. Unless there is another switch somewhere that detects if the case is removed.
  • Thanks for the quick response! Yeah, I just checked both with a multimeter. They both appear to be working properly. They both connect to ground when pressed which I'm guessing is correct.
  • Forgot to mention that I've also checked that the case removal switch works using a multimeter in beep mode. Have it temporarily taped down while working on it. Had issues previously with this switch where the laptop would suddenly shut off at random because the case screws loosened over time.
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