Video summary

Building a brand new NES in 2025 is EASIER than you think | The SM-Tendo

Main summary

Key takeaways

Technology

Overview

This video demonstrates how to build a “nearly brand new” Nintendo Entertainment System (NES) in 2025 by pairing salvaged original chips (CPU/PPU) with a modern, newly designed replacement motherboard and optional add-ons.

The focus is on:

  • Using surface-mount (SM) manufacturing for reliability
  • Removing legacy limitations
  • Upgrading video output quality beyond typical composite/RF

Core Project: SM-Tendo “Brand New” NES Motherboard

SM-Tendo motherboard (Zachor)

A new NES motherboard designed for easier manufacturing and assembly.

  • Surface-mount components (“SM” = surface mount)
    • Components are pre-assembled
  • Requires only the original NES PPU and CPU
  • Includes sockets for CPU/PPU
    • Avoids soldering the main chips onto the new board

Engineering tweaks vs. the original NES

  • Removes the CIC region lockout chip
    • Region lockout dependency is eliminated
  • Adds expansion audio capability
    • Inspired by features similar to Japanese Famicom systems
    • (Not originally present on NES)

Video Output Options (AV Solution)

1) PO Block (Zachor)

  • Provides composite video output via the PPU output path
  • Uses a more efficient power/video circuit than the original NES RF setup
  • Includes an extra output location for a future upgrade (see PPU Digitizer)

2) PPU Digitizer (optional mod)

Enables high-quality digital-style video output labeled “Luma code”, aimed at “almost HDMI-level” crispness.

How it works:

  • Extracts a pure digital video signal from the NES PPU
  • Converts/encodes it into Luma code
  • Requires an external scaling/conversion device (not a direct-to-TV solution)

The video shows decoding/process using:

  • OSSC (Open Source Scan Converter) with appropriate firmware/settings to convert Luma code into a standard display format.

Key takeaway: it’s not truly plug-and-play—it depends heavily on OSSC support and configuration.

Cartridge Connection Improvement: Nintend Drawer

The build uses Nintend Drawer for a more reliable cartridge interface than the original NES spring/push-down mechanism.

  • Uses a sliding insertion/removal action
  • Mentioned as V2 revision
    • Improves construction (an injection molded sled instead of 3D printed)

Shell / Product Build Quality

  • Uses an injection molded translucent purple NES shell from Retro Gamer Store
  • Praised for aesthetics and fit, but includes an important warning:

Warning: screw holes may be too narrow

  • The presenter notes the screw holes may not fit some original screws cleanly
  • While adjusting the cartridge door retaining clip, the presenter:
    • Breaks off a screw head
    • Notes it can’t be easily fixed
  • Recommendation:
    • Use narrower screws or drill holes slightly larger

Tutorial / Guide Elements in the Video

The video functions as a step-by-step build guide.

1) Disassembly & salvage

  • Start with a damaged/“wrecked” NES donor unit
  • Desolder/remove through-hole components
    • Remove expansion port
    • Then remove CPU/PPU (chips are later reused)
  • Uses:
    • Fresh solder
    • A Hakko desoldering gun to speed removal

2) Install the SM-Tendo motherboard

  • Prepare the new SM-Tendo board
  • Install the expansion port
    • Presenter clips off “guide pegs” that interfere with seating/soldering
  • CPU/PPU installation:
    • No soldering required (they press into pre-installed sockets)
    • Requires careful alignment and some “brute force” handling

3) Install PPU Digitizer (optional)

  • Align digitizer correctly to pin 1
    • Pin 1 identified via a dimple
  • Solder it on
  • Wire Luma code output connections:
    • Black → ground
    • Red → Luma

4) Assemble PO Block & wiring

  • Optional RCA jack for digitizer/Luma output
  • Install JST connector for routing the Luma signal
  • Connect PO Block to the SM-Tendo motherboard
    • Via header pins or wire/cap-leg style approach
  • Critical wiring note:
    • A ground wire from a PO Block through-hole must connect to motherboard ground plane
    • Presenter forgot this initially, causing the console not to power on

5) Final assembly checks

  • Confirm correct power/reset harness/connector style from the kit
  • Avoid controller port confusion:
    • Don’t mix up Player 1 vs Player 2 wiring
  • Delay soldering certain header pins until spacing/alignment is verified

6) Bring up Luma code video with OSSC (configuration guide)

  • Video quality initially looks poor until OSSC settings are tuned
  • Uses:
    • OSSC firmware 1.1a
    • On-screen/remote menu tuning on the OSSC
  • High-level setting workflow shown in the video:
    • Video processing → Luma code mode: set to NES
    • Sampling: advanced timing 256x240
    • sampling phase set to 28
    • Guy offset: set to 140
    • Sync option: ADC PLBW changed from “High” to Medium
    • Output processing:
      • set 240p → 88p
      • then use line5x processing mode to 256x240 optimal

Reported result:

  • After tuning, the image becomes crisp
  • Still reports some artifacting, suggesting potential improvement with:
    • future firmware
    • further tuning

It requires OSSC support and does not work out-of-the-box.

Pros and Cons (Review-Style Assessment)

Pros

  • Revives otherwise unplayable consoles (extends retro lifespans)
  • Beyond-original feature set
    • Adds expansion audio (Famicom-like capability)
  • More reliable cartridge loading via Nintend Drawer
  • Easier CPU/PPU integration using SM-Tendo sockets
    • Minimal soldering for the main chips
  • Shell is high quality aesthetically (with caveats)

Cons

  • Shell screw-hole sizing issue may cause damage during assembly
  • PPU digitizer setup is finicky
    • Requires careful OSSC configuration
    • Some artifacting remains (may improve with future firmware/tuning)
  • PPU digitizer requires extra hardware (OSSC) and isn’t plug-and-play

Price Breakdown (As Stated)

  • SM-Tendo motherboard: $65 (Zachor; includes JST cable for power/reset)
  • PO Block: $35 (recommended)
  • PPU digitizer: ~$50 (optional)
  • Nintend Drawer: $55
  • Aftermarket shell: $110 (most expensive item)

All links are stated to be in the description.

Main Speakers / Sources

People / roles referenced

  • Speaker/host: Tito (channel: “Retro Renew”)
  • Core project creators referenced
    • Zachor (SM-Tendo motherboard and PO Block; kit-related work)
    • Red herring 32 (foundation: NES motherboard reverse engineering)
    • Copper Dragon (Luma code concept/origin)
    • Marx 85 (help mentioned for OSSC/Luma debugging/tuning)
    • Andy (donor NES provided to the presenter)
  • Referenced makers/companies/products
    • Retro RGB (connected presenter to donor/contact Andy)
    • OSSC (Open Source Scan Converter; firmware requirements)
    • Retro Gamer Store (shell supplier)
    • Nintend Drawer (mod product referenced; specific maker not named in subtitles)

Original video