You might remember my glitchy Mario from a previous blog post. Basically I thought my copy of Mario 2 was just old and glitchy, but it appears that it’s actually the Famicom Disk System RAM Cart that was causing the issue!
I googled it and found this particularly useful blog post by synt4x and I’m here to confirm that this works super well! It’s worth noting that the particular FDS Board I have is a HVC-FMR-03.
As syt4x explains in their blog, the PRG lines of the FDS RAM Cart seem like they receive some interference, so by adding in a 9pin 4K7 Resistor Array to these pins, we help ensure there’s no signal interference.
I ordered my 4K7 Resistor Array from this seller on Aliexpress, it took close to two months to arrive so probably try find some a bit closer to home if you’d like this fixed quickly!
The actual soldering job is quite easy:
- Bend the first pin on the Resistor Array (RA) up.
- Line up the remaining pins:
- RA Pin 2 to FDS Pin 6
- RA Pin 3 to FDS Pin 7
- RA Pin 4 to FDS Pin 8
- RA Pin 5 to FDS Pin 9
- RA Pin 6 to FDS Pin 10
- RA Pin 7 to FDS Pin 11
- RA Pin 8 to FDS Pin 12
- RA Pin 9 to FDS Pin 13
- Put a bit of tape on top to hold it in place while soldering.
- Solder the above pins to each other.
- Solder some wire to RA Pin 1 (I used 30 AWG wire)
- Solder other end of wire to the above spot on the FDS Board
Here’s another couple of pictures to get a better idea:
Here are the results!