pt0025 - NESessity v1.3 (
bare PCBs Only). 3 circuit boards are included: The NESessity v1.3 motherboard and the A/V + power PCB that replaces the original RF modulator box. This is a new PCB for the Nintendo Entertainment System (NES) with new features designed by Low Budget in United States of America. Upgrade and/or repair your 30 year old Nintendo NES with this new design motherboard. The NESessity is a top quality replacement motherboard for your front loader NES console with a variety of new features and easy customization options. Circuit is based on a complete reverse engineering of the original system for 100% pixel prefect gameplay and compatibility. 3 circuit boards are included: The new NESessity v1.3 motherboard, a PCB that replaces the original Power/AV module, and a PCB for RGB and s-video out connectors. The new power & AV PCB connects to the main circuit board with a 8 pin JST connector. RGB and s-video output is only available when building the NESessity with the NESRGB add on.
Designed for easy assembly, all components are through hole (with the exception of two SOIC chips.) The full bill of materials is available at the bottom of this page as an excel file. Please note that CPU and PPU chips are required to be de-soldered and removed from the original NES. Aftermarket clone chips are readily available from Aliexpress and can also be used (although these will have sound issues and are not compatible with some games.)
- CPU: RP2A03 (original) or UA6527 (clone)
- PPU: RP2C02 (original) or UA6528 (clone)
The NESessity is designed to install in NTSC systems. Building a PAL compatible system is possible by using the correct PAL CPU (RP2A07) and PPU (RP2C07) chips along with a 26.601712 MHz crystal. Famicom games can be played but require a readily available cartridge adapter.
Improvements over v1.2
- When using a 7805 linear regulator, there's now room for a very large heatsink to eliminate overheating issues completely. Fits with original RF shielding too (some minor cutting of top RF shield required.)
- Additional solder pads for power switch that allow compatibility with Borti NES I/O board option.
- Several component footprints have been improved and some trace routing optimization.
Features:
- Works and installs just like the original part in your original front loader console.
- Region free; Famicom games require cartridge adapter.
- 15p Famicom expansion port replaces the original 48p NES expansion port.
- Adjustable stereo sound with auxiliary sound input from NES cartridge pin 54.
- Can be assembled with or without original RF shielding.
- No lockout chip; uses reset circuit from top loader NES.
- PPU is in same location as original NES so any video mods that fit original will fit NESessity. Compatible with NESRGB and Hi Def NES video mods.
- Can use original AC NES power adapter or modern 12v DC power adapter.
- Can be used with 5v switching regulator or 7805 style linear regulator.
- RCA connectors for composite video and stereo sound.
- Works with original power / reset button PCB (requires small modification.)
- Compatible with Famicom accessories: Light Gun, 3D Glasses, 4 player adapter. Some accessories may require a db15 extension cable to physically plug them in.
- Supports Famicom microphone and has LED to indicate when input is active.
- Ventilation holes for improved cooling.
- Premium quality PCBs have thick 2oz copper finish.
What's included?
- unassembled NES motherboard replacement PCB
- unassembled power / AV PCB (to replace original power/RF modulator)
- 8p mini DIN / 4p mini DIN connection PCB for RGB / s-video out
What's required?
- Original NES CPU and PPU chips (recommended) or aftermarket clone chips
- Parts listed on B.O.M. Almost everything is available from Digikey
- (Optional) NESRGB kit for RGB & s-video
- (Optional) Reused 5 pin connector for power/reset PCB
- Reused crystal from original NES (this can be hard to find new)
- The original front loader NES system case
Assembly Notes:
The original power / reset button PCB requires a simple modification; the polarity of the power indicator LED needs to be reversed. The v1.3 bill of materials is identical to the v1.2 BOM. It is not necessary to assemble any of the Famicom microphone components marked with and asterisk in the parts list if you do not need this feature. Assembly guide available to download in .rtf format. Digikey parts list has been updated 6/20/21 and is available to download in excel format; should be able to upload to a Digikey shopping cart.
Specs and Docs
Datasheet
BOM NES Assembly Guide
Youtube How To:
