Old Apollo Wah pedal problems

Hey,
I dug out this old Apollo wah pedal I had. It's from around '74-'75. It used to work fine, but when I plugged it in to check it out it was picking up radio signals. What should I check out to get rid of that or is there something else outside of the pedal I should be checking? I'm not so electrical-tech savvy, so write SLOWLY.

Thanks!
Jonny

You can try a few different things:replace the cables from the input and output jacks to the circuit board with shielded cable.Solder a 100-220 pF capacitor from the input to the ground.Try to find the smallest one that stops the radio signal.If you still hear the radio you can shield the inside of the Wah Wah if the case isn´t made of metal.I have never needed to do more than the two first things.