hp envy 15t k000 debugging

[tommy1331]

Hi, I'm quite new to this, I am trying to debug a faulty motherboard (DAY31AMB6C0). There was a fault in the DC input circuit with a faulty TVS diode after the first MOSFET shorting the VAD rail to ground. I was able to clear that fault by removing the diode and now the input section seems to be working correctly and I get the V3PCU power rail.

But trying to start the board still fails, I put some RAM in it and shorted the power button to start it up but it only blinks the power LED in the DC jack assembly 3 times. Maybe the AC detect circuit is broken? Or is this more likely to be an EC issue? I see in the schematics the EC handles the IO for the power button so it seems it's not completely dead, but it's also keeping MAINON low.

3v seems to be missing along with the S5 power states, I think S5 should be available even when the laptop is off right? HWPG seems to also be lower but maybe that's expected when the laptop isn't on.

I tried measuring the voltages on the different rails while pressing the power button to see if anything changes when it blinks the LED but it happens really quickly so it's a bit difficult to measure.

EDIT: v3 seems to be generated by APL3523A only if MAINON is high, so that explains why it's missing at least.

[tommy1331]

I went back and checked everything again and actually the board boots fine from battery now, and the adapter I was testing it might be the actual issue, the AD_ID seems disconnected in it. Looking at the schematics it looks like that would result in the 90W power supply being detected as a 65W power supply. Is there a way to force boot off of a power supply ignoring the AD_ID check or do I need to fix the power supply plug before debugging further?