OpenTendo NES Replacement Motherboard


The OpenTendo is a brand new replacement motherboard for the Frontloading Nintendo NES designed by Redherring32.


  • Identical (or better) performance to original NES motherboard.
  • Stays true to the original: reuses main chips from your original board – CPU, PPU & lock-out chip (optional).
  • Compatible with NESRGB.
  • Additional footprint for optional expansion audio.
  • High-quality matte black PCB with gold ENIG finish.

Please note: we are only supplying the PCB! You will still need to acquire the parts and assemble them to the PCB. Please see below for more information.

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SKU: NES-OT Categories: , Tags: , , ,


This is the V1.2 board. In addition to the components in the BOM (here), you will also need to source the following parts:

  • x1 CPU RP2A03 (NTSC)/RP2A07 (PAL) from original Famicom/NES or UA6527 (NTSC)/UA6527P (PAL) clone.
  • x1 PPU RP2C02 (NTSC)/RP2C07 (PAL) from original Famicom/NES or UA6528 (NTSC)/UA6528P (PAL) clone.
  • x1 Lock-out chip from original Famicom/NES or NullCIC replacement.
  • x1 30pF trimmer capacitor.
  • x1 4-resistor 6.8K common bus resistor array.
  • x2 2 DAN601 diode arrays.
  • x2 UPA64H diode arrays.
  • x1 1 2SA937 transistor.
  • x2 2 2SC2021 transistors.

Note for PAL consoles: If you wish to use the board in a PAL console, you will need to use a PAL CPU, PPU & PAL crystal (26.601712MHz) instead of NTSC.

Please note: By purchasing this board, please understand that it is DIY & for advanced installers only. Whilst we’re happy to offer support with any install questions, we cannot offer one-to-one guidance through the install process! More information on the project can be found in the github by clicking here.

Thanks to Redherring32 for the Opentendo project!

Additional information


Board Only, Board + NullCIC (replacement lock-out chip)