Famicom Disk System

What You’ll Need

Parts

• Parallel Cable with male connector (DB25) or D-sub connector & hood
• FDS RAM Adapter disk drive connection cable
• USB cable
• Small project box
• Small, round stickers, numbered 1 through 25
• Heat shrink tubing
• 2 small zip ties
• Electrical tape

Tools

• Soldering iron & solder
• Wire stripping tool
• Screwdriver
• Dremel tool with small grinding bit
• Multimeter

Step 1

Take the DB25 parallel port cable, cut the wire, and strip off about three inches of the plastic sheath and metal shielding.

Step 2

With a multimeter and wire strippers, strip about an inch if insulation from each wire one-by-one and check each using the continuity setting. Label the wires on the DB25 cable one-by-one with small round stickers denoting the pin number to which each wire corresponds. If you’re using a D-Sub Hood and connector, you can simply solder the wires to the pins listed in the chart below.

Specifically, you’ll be looking for the following wires/pins (BLUE box, DDU aka DB25 column, from fdsloader.txt file):

On the DB25, pins 3 though 9 and pin 16 are unused for this project. When you find the wires for these pins, cut the wire off at the base of the shielding. Pins 18 through 25 are ground pins. The wires for these pins should all be soldered/connected together.

Step 3

Prepare the FDS disk drive cable by disconnecting and removing it from the RAM Adapter. If you prefer to not build a connector to plug the existing wire connector into, simply cut off the connector and prepare the wires by stripping off about an inch of plastic wire insulation.

Step 4

Now you can begin connecting the wires. The picture below shows which wires on the disk drive cable correspond to the letters and numbers from the above chart (FDS column). Connect each wire from the GREEN box (FDS column) to the corresponding wire on the DDU/DB25 (BLUE box) as noted in the above picture. For example, the green wire (#1) on the disk drive cable connects to pin #14 on the DB25 cable. I’d suggest just twisting the wires together or wiring them to a solderless breadboard first to test the unit before soldering and using heat shrink tubing or electrical tape on the connections.

Step 5

Prepare your USB cable by determining which wires are the power (5V+) and the ground wires using a multimeter. These wires will typically be RED for 5V+ and BLACK for ground. Once these have been determined, cut the remaining wires down by the base of the shielding to prevent mistakes in wiring. Double check the voltage coming from your computer’s USB port. If it’s greater than 5V, you can add a 7805 voltage regulator to drop it back down to 5V.

Step 6

For the ground, connect the brown wire (#4, outlined in brown in the above chart) of the disk drive cable to pins 18-25 of the DB25 cable. Also connect the USB’s ground wire to these wires. Shield these wires with electrical tape or heat shrink tubing.

Step 7

For the 5V+ DC power, connect wire #2 (light blue) of the disk drive cable to the USB 5V+ power wire.

Step 8

Test the unit on your computer with FDSLoader. If it does not function correctly, check the computer’s parallel port settings and the cable’s wiring.

Step 9

Once the unit works correctly, solder the connections and use the heat shrink tubing to prevent short circuits.

Step 10

Using a Dremel (or similar) tool and bit, cut out the holes in the project box for the wires to pass through so the connections can be inside. Once this is completed, add zip ties to the wires to keep them from pulling on the connections and secure them in the project box.

Here’s what your completed FDSLoader disk drive dump cable should look like:

Step 11

Re-check your cable to ensure it works correctly and then have fun dumping disks. Remember that the FDS drive still needs the AC adapter connected to it for the dump cable to function.

As a side note, current disk dumping methods result in dumps that are missing 2 bytes of GAP data and 2 bytes of crc16 checksum data. However, the disk dumps will still work for rewriting and emulation.