There are several schematics for the Famicom, but they're all a little different. It's not clear if this is from different board revisions, mistakes, modifications, etc. So, I thought I'd trace a board that I had already depopulated for another project.
The main goal was to make an accurate schematic, but I decided to recreate the PCB layout too. It's not perfect. I had to fudge some footprints, but they're in the ballpark. This would serve as a good starting point for making a replacement original board.
There are some oddities in the schematic, but nothing too interesting. A tristate buffer is abused into working as an amplifier for the audio. A few passives have a dotted outline, indicating that they're not usually (ever?) populated. The oscillator circuit is little different from other schematics. Files are on my github here.
Here are the new traces overlaid on a scan of the PCB. This highlights the accuracies and inaccuracies.
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| Overlay |
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| New schematic |
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| New PCB top |
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| New PCB bottom |
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