NEO-AES board

First known version of the AES board, made (and maybe assembled) by NEC. Uses the first generation chipset, ,.

In later use of this board version, a video cleaner board was added.

Some consoles also have a metal shield connected to ground.

=Voltage protection=

The voltage protection circuit changed during the production of the board:
 * The first boards simply had no voltage protection. Meaning that using a higher than 5V power supply would fry everything.
 * Later on, components were added to dump excessive voltage as heat (see below).
 * Even later, the NEO-POWER-0 board was added as a factory mod to allow the safe use of 9V power supplies.

The voltage protection circuit starts operating as soon as the input voltage goes above 5.4V. If used with a 9V power supply for an extended period of time, it may fail due to excessive heat. Q2 and/or D1 may need to be replaced.



=Board map=




 * 1A: Power supply barrel jack connector
 * 1C: Audio/video output DIN connector
 * 1F: Main clock circuit
 * 1I: 68k user RAM chips
 * 1J: System latch
 * 1KL: System ROM
 * 1OPQ: Analog sound circuit
 * 2EF: Video DAC
 * 2Q:
 * 3B: Video encoder and color burst oscillator
 * 3EF: Palette RAM latches
 * 3HIJK: 68k CPU
 * 3LMNO: soundchip
 * 4F~M: Cartridge slot
 * 4PQ: Palette RAM chips
 * 5CD:
 * 5FG: L0 ROM
 * 5IJK: Z80 CPU
 * 6M: Z80 RAM
 * 7B: Slow VRAM chips
 * 7C: Reset button
 * 7H:
 * 7K:
 * 8E: Fast VRAM chips
 * 8OPQR: Memory card slot
 * 9C: Voltage protection circuit
 * 9EF: Joypad input filters
 * 9HIJK: Analog sound circuit
 * 9LM: More joypad input filters
 * 10B: Power switch
 * 10F: P1 connector
 * 10H: Headphone 3.5mm stereo jack connector
 * 10J: Headphone volume slider
 * 10M: P2 connector