I have a Fairphone 3+ and today it turned off randomly, and it won’t turn on again.
It does not give any life sign and does not show up on $ lsusb on my laptop
I tried the following:
charge it with Laptop and power brick <= 3A & >= 1A
clean USB-C Port
checked the connections inside and the power button
removed the battery
It could be that your battery is bad, because the fairphone wont boot if the battery not present or not working properly.
Do you have another battery to try and switch them?
Yes sadly your problem form the start didn’t seem like a battery issue.
Regarding the internal connections have you tried cleaning the earthing contacts between the display and core module. The ‘solder’ contacts outlined in red on the display.