Some of the more common issues we see here are problems relating to the wiring of the 3PDT "stomp" switch. There are typically 6 wire connections to be made to the footswitch in the customary true-bypass configuration, plus two jumpers--one between the 3 and 6 lugs, and the other between the 4 & 9. The #4 lug presents the additional complication of also requiring a wire connection from the PCB, so that lug tends to be the one we see get "buggered up" the most, especially by novice builders.
Something else to be aware of is that the body of these footswitches is made of plastic, and if you get enough heat into it while soldering on the lugs, that plastic will eventually melt. That can allow the lugs to physically move within the switch and mess up the internal switch connections, resulting in a switch that operates unreliably or not at all. For this reason, you want to make your soldering operations on the lugs as quickly as is reasonably practical. If you find a particular lug joint giving you problems, allow the switch to cool down for a minute or two between applications of heat.
One other preliminary comment--it is well worth taking a couple of minutes to test the function of your 3PDT footswitch with a multimeter before installing it. It is, by far, the most complicated mechanical component present in the typical pedal build, and "bad" switches are encountered from time to time. Check out THIS POST
from Stephen to see how to test your footswitch before installing it.
While there are several workable techniques for rigging your switch, here's the one that I favor. Before you mount your footswitch in the enclosure, install the 3-6 and 4-9 jumpers. I don't bother with wire for these connections, nor do they need to be insulated, when properly installed. I just use some component lead clippings from the PCB component installation process. For the 3-6 jumper, hold the lead cross-wise in the jaws of a needlenose pliers so that the length of the gripped portion of lead is about 1/4". Then just bend the leads over 90 degrees, forming a square U shape with the lead. Insert the two ends through the holes of the 3 and 6 lugs from the interior side of the lug array. Snug the jumper up against the two lugs and bend the protruding leads outward to hold the jumper in place. Solder the leads to the lugs and trim off the excess lead ends.
For the 4-9 jumper, use a straight length of component lead and just run it through the two lug holes. You want to use a thin lead, like a resistor lead, for this purpose, since thicker leads will be difficult to insert. It may take a little wiggling and finagling to get it through, and occasionally I find that I need to twist the lugs slightly with pliers to better align them (only do this with a cold switch). Once you have the lead inserted through the two lugs, solder ONLY the 9 lug end in place, and trim the lead at that end. Leave the 4 lug unsoldered, so that you can later insert your PCB connecting wire there. At this point, your switch should look like the first photo attached below. The switch is now ready to install in the enclosure. Orient the switch as shown in the kit instructions, making sure that the jumpers are in their proper positions.
I recommend prepping all of your PCB connecting wires at this point, if you haven't done so already. My standard sequence for this is:
- Measure wire lengths needed and cut, allowing some extra at both ends for stripping & soldering
- Strip about 1/8" of the insulation off the wire ends for connections going to the switch or the PCB. For the older BYOC kits that have footswitch connections directly to the I/O jacks, strip off about 1/4" for those connections. (NOTE: Some builders like to prep their wiring with longer stripped ends to allow enough for wrapping around the lug for a more secure mechanical connection prior to soldering. Strictly a matter of personal preference.)
- Twist the wire strands together as tightly as possible, using a spiral twisting motion between your thumb and forefinger.
- "Tin" the twisted wire ends with a small dab of solder. The idea is to just wet the strands with enough molten solder to bind them together. You do NOT want a "blob" of solder on the wire end.
Once your connecting wires are prepped, solder them to their respective eyelets on the PCB (or to the appropriate I/O jack tab on the older kits). Mount your PCB into the enclosure per the kit instructions. Now solder the remaining wire ends to their appropriate footswitch lug locations. The technique that works well for me is to insert the tinned & twisted wire end into the lug hole up to the insulation, and then bend over the wire end with the blade of a small flathead screwdriver. This holds the wire in place in the lug and frees up both hands to do the lug soldering. I generally hold the tip of the solder iron (well-tinned for good heat transfer!) against the side of the lug and then touch the solder against the heated lug until it flows into the lug hole. Properly done, this should only take a couple of seconds to do. Avoid using too much solder--the joint shouldn't be blobby when done right. Remove the solder iron, allow the joint to cool for a few seconds, and trim off any excess protruding wire end with a pair of fine nippers (and the excess jumper lead on the 4 lug). I find it works best to solder the 1, 4 and 7 lugs first, and then the 2, 5 and 8 lugs in the middle row of the switch after that. Your switch should look something like the second photo below when you're done.