There are a total of four PCBs neatly stacked up to fit in the small AXX 200 chamber. It minimizes space. Saved space = bigger audio chamber = better audio.

To take out the stack of PCBs, first, disconnect the flex connector with tweezers.

After that, disconnect the two connectors. These are probably connected to the microphones at the top.

Lastly, disconnect the final connector that is linked to the battery from the bottom PCB.