Given that this is a proprietary board, official schematics are rarely public. Here are reliable methods:
Outlines the connections between the CPU (often an AMD E-series APU), RAM, and peripheral controllers. Power Distribution: bm5291 ver 1.3 schematic
If the original schematic is unavailable, you can design a drop-in replacement using a generic IC like the PT4115 or MP3388 . However, to match ver 1.3 behavior, you need: Given that this is a proprietary board, official