NESessity NES PCB Replacement

Low_budget, creator of the now-discontinued NES clone the Super 8-bit, just revealed his latest project: a complete replacement for the front-loading NES motherboard named the NESessity

Designed to fit perfectly inside of an original NES case, the NESessity board’s circuit is closely based on the Super 8-bit layout (Low_budget recently released its full schematics) but the final design is notably missing a Famicom cartridge slot and multiple video out options (S-video and RGB).

The NESessity is sold as a kit and it includes a bare motherboard PCB and a RF module replacement PCB. Low_budget posted a Digikey parts list on the project’s Tindie page for all the components that the user must provide for him/herself. Designed with easy assembly in mind, the motherboard uses THT (through hole technology) for most on board components, with the exception of two SOIC chips, the LM4808 and the LM324.

Just like with its fully-featured predecessor, the original CPU (Ricoh RP2A03 or RP2A07 for PAL) and PPU (Ricoh RP2C02 or RP2C07 for PAL) chips must be obtained (desoldered) from an original NES.

Here’s the NESessity full list of features:

• Works and installs just like the original part in your original front loader console
• 15p Famicom expansion port in the location of the original unused NES expansion port
• Optional Famicom microphone support
• Adjustable stereo sound with auxiliary cartridge sound input through pin 54
• Can be assembled with or without original RF shielding
• 2 reset modes selectable with jumper: NES front loader reset (with screen blanking) or Famicom style reset (cpu only)
• No lockout chip
• PPU is in identical location to original NES so any video mods that fit original will fit here (such as NESRGB or Hi Def NES)
• Can use original AC NES power adapter or modern 12v DC power adapter
• RF module replacement board has room for larger heatsink on 7805 regulator (can also be used with switching regulator)
• RCA connectors for composite video and stereo sound
• Works with original power / reset button PCB
• Compatible with Famicom accessories: Zapper, 3D Glasses, Family Basic Computer, and 4 player adapter (some accessories may require db15 extension cable)

The NESessity serves as a replacement for original boards that may have suffered from a bad desoldering job while removing the CPU and PPU chips, corrosion or ripped traces. It also improves over Nintendo’s design by adding a Famicom expansion port, stereo sound and completely removing the lockout chip turning the system in hand into a region-free console. (A 60-to-72-pin adapter is still required to play Famicom games).

Low_budget might release a later revision of his board that will feature RGB video out but that solely depends on how well the current product will fare.

Priced at 39$, the NESessity is now available for purchase through Tindie.

NESessity thread on the Shmups forums: https://bit.ly/2TmIOan
Purchase PCB-only on Tindie:  https://bit.ly/2ABvisX

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