jasoncoon, I've had this 6x6x6 L3D Cube for years. I finally decided it was time to dust if off and replace the built-in controller with a #PixelBlaze by @wizard!
Photo of the bottom black PCB of the L3D cube. A PixelBlaze Pico is secured in an empty spot, with the antenna near the edge, with red, blue, and black wires running from it to the main control PCB.
A closeup photo of the black PCB with the first LED's data in (DIN) pin labeled with blue masking tape. A blue wire is soldered onto the DIN pin. The resistor FB2 has been removed to sever the connection between the built-in controller and the first LED's DIN pin.
A closeup photo of the black PCB with a black GND wire soldered to the micro USB GND pad, and a red 5V wire soldered to a diode.