Chosen Solution
I recently bought a new 3ds xl it worked well until I accidentally took out the battery while it was running. I wanted to change the housing of it so I swapped it, but the problem started when I was testing if it’s working properly, I temporally connected the battery without the case it showed red light which means low battery so I thought need to turn it off so tried to press the power button but cause I was using both of my hands I needed to use one of them. my hand slipped and the battery just got disconnected… from what I searched it might be a fuse or diode problem but I don’t know how to read the multimeter. Update (11/18/2021)
did you check all the ribbon cables are seated right and just in case reseat them? if it is a diode you can test a identical one on the board to find the OHM reading and knowing that fine one that isn’t the same as the rest.
