Riffmaster Guitar Mod - 3.5mm Jack for Stomp Pedal (Overdrive Activation) for Rock Band and Fortnite Festival

I am a huge fan of RockBand and was extremely excited for the release of the Riffmaster Guitar controller. I was very saddened -- though not surprised -- that the jack for a tap pedal was not included in the controller design. It wasn't included in the RB4 guitars either, which was maddening, since it was probably one of the best features that the RB2 guitar had added. I modded both of my RB4 guitars to add a pedal jack by splicing in to the Left DPad wiring based on this instructable.

This project adds a pedal jack to the PDP Riffmaster Guitar controller by surface soldering wires on to the appropriate test points of the main PCB to "splice" in to the Left DPad. I think it came out pretty well, and it was easier than I thought it would be. Enjoy!

To add the jack to the Riffmaster controller, you will need:

• Small phillips head screwdrivers (to open the guitar)
• Soldering iron, solder, flux
• 24 gauge wire
• 3.5mm mono jack
• Hot glue gun and glue sticks

You will also need a non-latching pedal switch. You can use the pedal from a RockBand drum set, or you can buy something simple and cheap from Amazon or other. The items I bought and used are the following...

3.5mm Mono Jacks

24 Gauge Wire

====== Pedal for OverDrive Activation ======

Tap (Foot) Switch Pedal (non-latching)

3.5mm to 1.4" Male-to-Male Cable

Start by opening the guitar. You will need a P2 or P1 screwdriver to remove 8 screws from the back, 4 screws from under the pick guard and 4 screws from bendable neck area. The front and back screws are the same size. The screws in the neck are smaller, so keep these separate for ease of reinstallation later.

Once you have the back of the guitar case off, you should immediately remove the battery connection to the PCB so that you do not have any shorts. Just follow the wires from the yellow battery to the PCB and gently pull the connector out. I found wiggling softly back and forth helps to free the connector.

Now free all of the wires from the Main PCB by gently wiggling and pulling at the white connectors. To remove the ribbon cable, you must first pull the black crimp connector out so that the ribbon is released. I used my fingernail to get this done.

Now remove the two small silver screws holding the PCB to the case and the single silver screw that holds the audio jack onto the case. You will remove the Main PCB and the Audio PCB together since there is a black wire soldered between the two.

You should now have the Main PCB (and Audio PCB) free of the guitar case. It's a good idea to take pictures before you remove the wires and remove the board so that you know how to put it back together.

Once you have the Main PCB removed, you can flip it over and remove the silcone buttons of the DPad by pulling up gently to release the two "plugs". I confirmed via a voltmeter that test point 78 (TP78) was ground for the PCB. The two large rectangular copper areas are also ground if you'd prefer to solder to a larger contact area. Test Point 90 (TP90) is the "hot" side of the Left DPad button.

Add a dot of electronics flux to each of these spots and using as low a temperature as possible add a bit of tin/lead solder to each test point. Tin the ends of two 24 gauge wires, then attach them to the solder points by holding the wire flat against the PCB and touching the hot iron to the points. The tinned wire and pre-soldered test points should attach very easily. My solders are not very pretty, but they are solid and there is good conductivity and stability in both points with no bridging. I verified all of this with multimeter prior to the next step.

It is important to note the positioning of each wire so that they do not interfere with reattaching the PCB to the case. You need to make sure that the wire attached to TP78 (black) runs to the right so that it can be fed through an opening in the top of the DPad seat. The wire attached to TP90 (red) should run to the left so that it can be fed through an opening on the side of the DPad seat (see pictures in next step). Now reattach the silicone DPad buttons and make sure to firmly seat them by pull the "plugs" though until they click.

This step is simple as long as you have soldered the wires in the right orientations. Simply make sure that the wires are positioned in the openings in the DPad seat (top and side) as shown in the pictures so that the wires to not interfere with proper seating of the PCB in the case.

Now screw the Main and Audio PCBs back in to place.

Reattach all connection to the PCB, making sure that the wires run through the guides that keep them free of being kinked or cut by the screws.

I had at first hoped to be able to use a 1/4" audio jack for the pedal, but there was just barely enough space for a 1/4" jack, and I feared it would end up hitting the PCB. I did not want to risk it, though it could probably be done if one were really careful about it. So, I fell back to using the same 3.5mm mono jacks I used for my RB4 guitar pedal mods.

Simply solder the contacts of the jack to the wires. If you are using the same jack as I did, then solder the black wire to the contact that is set at 90 degrees from the axle of the socket. Solder the red wire to the contact that is furthest from there. The contact in the middle is unused (I cut it off). I also used heat shrink tubing to reinforce/protect the connections.

Now, hold the connector in position just to the left of the screw post that is below the PCB (see picture) and make a little mark on the outside edge of the case so you know where to drill a hole. Lay the jack and the wires somewhere out of the way in the top case and reattach the bottom of the case with 2 or 3 screws just to hold everything in place. Use a power drill to make a clean pilot hole with a 1/16" bit. Hold the drill tightly to make sure the drill doesn't 'lunge' in to the guitar and damage the PCB. Once you have a clean pilot hole, repeat with a 15/64" bit to make the hole fit the jack tightly. If you don't have that size, use 1/4" bit and then add a dot of hot glue to the opening to hold the jack in place. You get the idea: make it fit nice and snug.

Reopen the case (don't lose the screws)! Manually seat the jack in the new opening to ensure a good fit. Once you are happy that it is seated correctly, apply copious amounts of hot glue via glue gun to build up a base for the jack and secure it in place. Once the glue started to cool, I put the bottom of the case back on and just held it shut for 5 minutes while the glue did its final hardening to make sure the jack was held in place properly.

Make sure all the wires are in their proper positions. Add a dot or two of hot glue to keep the new wires in place and out of harm's ways.

Close the case and apply all the screws (4 to the neck (accessible in folded position), 8 to the back of case, and 4 to the front of case). Reattach the strap connector (screw it in) and the pick-guard (snap it down) to your Riffmaster.

Plug in your pedal and ROCK OUT with foot activated OVERDRIVE in RockBand4 and Fortnite Festival. ENJOY!