I will also add:
1 Welcome!
2. Some of the carbon pile resistor pedals can be rebuilt. The Singer ones are the most common ones to rebuild but some of the others are doable as well. Sometimes it's the carbon disks inside have been broken (they're very fragile and can be broken when the pedal is dropped.) or escaped which means there's too much gap to take up and so the machine doesn't respond to the pedal until the pedal reaches the shorting bar - full on. If it just starts going as soon as you plug it in, it's what Rodney says. If you press on the pedal and get nothing nothing nothing full tilt boogie....it's the pedal. If it races sometimes but not all the time even if the pedal isn't depressed - it's likely the wiring.