For what it’s worth, I found [https://www.aonemobiles.com.au/2020/03/microsoft-surface-pro-4-no-power-no-schematics-no-problem/|this site] that seems to have a possible solution. I just replaced a bloated battery pack in mine and get no reaction to the power button. I checked my 3.3v rail and only was getting about 270mv so I ordered a 5 pack of the ITE chips off of aliexpress a few minutes ago to try out. If it fixes it, I will update, but it’ll be a few weeks.
+
+
+
+
PS: I know this is over a year after the initial post. Just trying to put it out there for future searchers.
For what it’s worth, I found [https://www.aonemobiles.com.au/2020/03/microsoft-surface-pro-4-no-power-no-schematics-no-problem/|this site] that seems to have a possible solution. I just replaced a bloated battery pack in mine and get no reaction to the power button. I checked my 3.3v rail and only was getting about 270mv so I ordered a 5 pack of the ITE chips off of aliexpress a few minutes ago to try out. If it fixes it, I will update, but it’ll be a few weeks.