DIY Upgrade: UM6561 Chip in Yuxing PC

If you're into DIY upgrades for student computers, this article is worth checking out.

We're taking a closer look at one of the earliest Yuxing New Century Type-A multimedia PCs. This machine features a full version of the UM6561 processor—not a cut-down variant—complete with exposed 50/60Hz and PAL/NTSC pins, making it super convenient for selecting your preferred video output standard.

What makes this chip particularly interesting is that it integrates everything: CPU, PPU, PSG, RAM—all on a single NES-On-A-Chip (NOAC). It requires only minimal external components: just a few resistors/capacitors and a crystal oscillator, which makes it both easy to work with and a great piece for collectors. You can even follow along and modify an FC84 circuit diagram, have a custom board made, and drop it right into an original Famicom case.

Here's what you need to cover:

Yuxing New Century Type-A and select Type-B motherboards

The processor is on a separate PCB, making it ideal for DIY transplants.

UM6561 pinout diagram — Important note: the 80-pin configuration used in the Yuxing Type-A does not directly match this pinout, so proceed with caution.

Dendy Junior schematic with UM6561F-2 processor, useful as a reference for your peripheral circuit design.

Original Dendy schematic with UM6561 processor, another helpful guide for external component layout.

That's it!