As I don’t have any more ideas I’d like to ask around here.
Got a broken Switch “does not turn on”.
Identified and changed a shorted M92. The Switch started booting again up to the switch Logo.
I reflowed and somehow f*cked the wifi chip bga array (shorted after reflow because I knocked it to hard). So I removed, cleaned and resoldered it and the short was gone. But the unit still stops at Switch Logo.
I finally replaced the wifi chip with a harvested one but no luck (still stuck).
Someone here suggested that missing Caps left to the CPU shield could cause this issue - and indeed one little cap was missing there - replaced again with a harvested one. But still stuck.
As a last resort I changed the BQ. Shortly after that the MAX89??? On the back “blew” and brought the nearby coil to boiling-temperature (I posted on that in another thread). I replaced both and am now where I started “stuck at the switch Logo”.
Hopefully any of you has an idea how I could proceed?