Category Archives: Famicom Disk System

Fix Glitchy Famicom Disk System Sprites!

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:

  1. Bend the first pin on the Resistor Array (RA) up.
  2. Line up the remaining pins:
    1. RA Pin 2 to FDS Pin 6
    2. RA Pin 3 to FDS Pin 7
    3. RA Pin 4 to FDS Pin 8
    4. RA Pin 5 to FDS Pin 9
    5. RA Pin 6 to FDS Pin 10
    6. RA Pin 7 to FDS Pin 11
    7. RA Pin 8 to FDS Pin 12
    8. RA Pin 9 to FDS Pin 13
  3. Put a bit of tape on top to hold it in place while soldering.
  4. Solder the above pins to each other.
  5. Solder some wire to RA Pin 1 (I used 30 AWG wire)
  6. 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!

Adding Games to the FDS Stick

I’ve written this guide mainly because I had just a little bit of trouble figuring out the FDS Stick, I’ll try keep it short.

Long story short, I expected it to be as easy as plugging it in, a folder pops up, drag games to folder and plug into the RAM Cart and off you go…

Adding Games:

1. Download and run the FDS Stick Software:

Plug in the FDS Stick and run the software, it should look like this:

If you see “not connected” where the “256M” is, plug your FDS Stick into a different USB Port, click Disk, then click back to Flash.

Click “Add…” then browse to the folder you store your FDS game backups and select a game, you should see something like:

You MUST click “Apply” for this game to be written to the FDS Stick, if you do not and take the FDS stick out of the port, nothing will have changed. Likewise, if you click “Remove” on a game you MUST click “Apply” for it to take effect.

Once you hit “Apply” and the progress bar fills up you are good to go! Unplug your FDS Stick from your PC and plug it into the Famicom RAM Cart:

It is important to keep it accessible as you will need to use the button.

If you add just one game, the FDS will boot straight into it. However, if you add more than one game, you will be presented with a game list:

From here, simply select the game you wish to play and it will boot up.

Some game require loading both “sides” of the Game Disc into RAM before you can play, Zelda is one such title, so when you boot it up you get this screen:

The Japanese text under the Zelda logo is asking you to insert “Side B” of the Game Card, this is where our button comes in handy.

One click of the button changes the loaded Game Card to “Side A”

Two clicks of the button changes the loaded Game Card to “Side B”

Holding the button ejects the Game Card.

It is important to remember that the FDS Stick is a Famicom Disk Reader Emulator, the games are not modified in any way, and still wait for the hardware signals that tell it the Game Card has been ejected, turned over and reinserted.

It is also important to note that if you are already on “Side A” and you press the button once, it will read as you having ejected the Game Card, turned it to “Side A” and reinserted it. It does not retain any contextual awareness of what side was previously inserted, so if like me, you though, just pressing the button once would “flip the disk” you are wrong!

Anyways, with this knowledge, when you are at the above screen in Zelda, simply press the button twice and you will be greeted with a black screen that says “Loading” and eventually you will end up here:

Have Fun!

Potential Issue:

One thing I have noticed is that there is no way to Load “Side B” first. For instance, Super Mario Bros. 2 is entirely on “Side A”, however, “Side B” contains a whole other game, Volleyball. In a regular FDS Drive, you would just load “Side B” facing up and it would boot straight into Volleyball.

If you have any questions please contact me on twitter!

Famicom Disk System + FDS Stick

Quick History Lesson

Famicom + Famicom Disk System

The Famicom Disk System was an addon for the Nintendo Family Computer (Famicom) released back in 1986. It used an entirely new system of loading games for the Famicom, in the format of Game Disks, which were essentially a proprietary sized floppy disk. The FDS unit itself comprised of two parts, the Disk Reader (large red unit) and the RAM Cartridge. The RAM Cart slotted into the Famicom’s cartridge slot, with a cable coming out of it that hooked into the Disk Reader, you then inserted your Game Disk, powered on the console and loaded your game into the RAM Cart’s memory!

Disk Reader (Red) RAM Cart (Black)

The Problem

Game Disks, like their floppy counter parts are subject to wear and tear. They contain a floppy magnetic disk inside, which has the game data written to it. This can become an issue with age as the disk might begin to fail through sheer use, data on the disk can become corrupt due to rogue magnetic fields and magnets can straight up destroy all data on a disk if it gets too close!



The FDS Stick

FDS Stick

The FDS Stick is a USB stick with 256 megabits of flash storage, however, it also has a port that connects directly to the Ram Cartridge and allows the FDS Stick to act as a Disk Reader Emulator! The special thing about this is that instead of emulating a game running on the console, you are emulating the hardware supplying the game data TO the console.

This means that the gameplay you experience is the 100% console accurate version of the game, no input lag, no miscalculated emulator code, just raw game, assuming of course that the copy of the game you are playing is unaltered!

I used to play a lot of emulated games before I started collecting, so I have no real qualms if people did want to use the FDS for that, but personally I’m just going to keep copies of the games I own, adding more as I collect more and play them from it to help preserve the actual Disks.


A Wild Glitch Appears

Glitched out Mario ;_;

I recently purchased an FDS Stick as when I booted up my copy of Super Mario Bros. 2, the japanese version of which, was only released on Famicom Disk, was glitchy! I naturally just assumed this was caused by my particular copy of Super Mario Bros. 2, I bought it used in Japan and it’s at most, 32 years old… So instead of risking buying a second copy, only to have it also be glitchy and given the fact that none of my other FDS games exhibit any odd glitches like this, I decided to buy an FDS Stick and I’d try a pristine copy sourced from the internet. Since I own the original, I don’t have any issue with doing it this way.


Well, when I got the FDS Stick, I went straight to an emulation site, had my antivirus pop a warning and immediately found a safer one. There I downloaded a copy of Super Mario Bros. 2, thenĀ  I struggled to figure out how to copy the game to the FDS Stick, I assumed it would pop a folder open and just drag and drop, but nope. After struggling to find anything on the internet to help, I just figured it out by myself.


Well, what happened next was totally unexpected. I hooked it up to my Famicom, it loaded into a menu where I could pick the ROM I wished to play, selected Super Mario Bros. 2 and the screen went black, text scrolled up and the game started, and I swear, it looks clearer than the Disk version, which I don’t think it actually is but it definitely looked it. Anyways, I start the game and log and behold THE EXACT SAME GLITCH!


This really bamboozled me, the only two explanations I can think of are:

  1. My copy of SMB 2 is the EXACT COPY this scene group ripped and put on the internet 20 years ago.
  2. Something is up with my FDS RAM Cart.

synt4x’s Glitch

I googled it and found 1 blog by synt4x who had experienced the same thing, the glitch in their picture even looks the same. Mine doesn’t seem as bad as that, however it seems the issue is not with copy of the game or the FDS Stick, but with the RAM cart itself.


So with the information I gained from synt4x’s blog, I ordered some resistor arrays and will attempt the fix myself when they arrive. In the mean time I’m going to disassemble the RAM cart and give everything a really good clean just to make sure it isn’t something as simple as that.

If/when the time comes to modify the cart, I’ll do my best to document the procedure and write it up, though it doesn’t look majorly complex.


You can get yourself a FDS Stick from the source over here: (I’m not in any way affiliated with them)

I’ll write up a short guide on how to use the FDS as I couldn’t find any material on it myself and just brute forced it into working. I’ll replace this line with a link when it’s done.