CD-ANA-2 board
The CD-ANA-2 board is the audio, video and power board for the front-loading NeoGeo CD. It was later modified and named NEO-CDA in top-loading systems.
Audio part
CN5 provides digital and analog audio from YM2610. CN10 provides I2S digital audio from the CD drive.
MONO goes to the video encoder for amplification and output to the DIN connector.
ON button part
The circuit is a fairly complex toggle switch with power-on reset and debouncing.
POWER is constantly at 5V when the power plug is connected.
VCC goes to 5V when STARTUP goes low.