If you're following this blog regularly (I hope you do), you'll remember the post about the French NES which I fixed and modded so it would have regular composite video output.

Another thing I wanted to change about this console was its power source. It comes with a 9V barrel power jack.

However, internally this gets transformed to 5V before it reaches the mainboard or other components. Hence, I figured I could simply remove the block with the (now unused) RGB output and 9V jack.

Then I stripped the board and its power and RF components off this block, leaving only the metal frame.

I had a set of USB-C ports lying around that even had fitting screw holes for the metal frame. Nice coincidence!

So I attached a USB-C port to the frame and mounted it back into the console case. The small breakout board of the port made it easy to connect a 5V and ground wire to it. The picture below shows where the 5V are connected to the NES' mainboard.

Note: The only thing you have to take care of is to connect the power button correctly as it now needs to switch the 5V from the USB-C on and off. You have to run the 5V wire to the switch and back to the board.
The reset button however is not affected by this mod, as its logic is handled by the board itself.

One thing I noticed when powering on the NES was a slight hum - some audio distortion. Usually, audio hardware is sensitive and requires very clean signals which appeared to be a problem with my USB-C adapter. Using a better adapter almost fixed the problem but adding a 1000 μF capacitor to the USB-C input turned out to be the better general solution.

So, that was it? We're done now right? ... well, almost.

Bonus - Disabling the Lockout Chip

Another thing that had been bothering me for a while was that one of my cartridges (California Games ☀️) simply would not work with this console. I had bought it from a trustworthy seller who had assured me that it had been tested fine. So I had closer look and indeed found this disclaimer on the box.

CAUTION: This Game Pak can only be used with the Mattel version Pal System of the Nintendo Entertainment System.

Hmmm ... the Mattel version ... was that the problem? I did some digging and apparently it was.

The NES' lockout chip that should actually prevent the spread of unlicensed games also prevented playing this game on my NES (all other games I had worked fine).

So I went for the tried and true lockout chip disable mod.

• Locate the chip labelled 3195A (or 3193A).
• Locate pin 4.
• Cut or unsolder it from the board and lift it up.
• Connect it to 5V.

All done! The NES is powered by USB-C now and running all my cartridges!