Tech9
Part of the Furniture
have you seen other models besides the 86U? I mean the boards.
Yes. All PCBs are different with different layout. Consumer products are made similarly with cost saving first in mind. Most use very close to SoC manufacturer suggested reference design in order to save on engineering. Some designs work for many years, some fail in few years. Tech companies don't like repair guys anymore. Some fruit logo companies use unmarked custom ICs or serial numbers coded in firmware to prevent repair attempts. I don't have too many posts on this forum and a quick search will tell you what I do and why.