I have an Electro-Harmonix switch blade channel selector I bought back in the 70’s. The issue I have is it was modified in the 70’s, to be just an on/off foot switch. I want to return it back to it’s original functionality. However I need a wiring diagram. I might be able to get by with a close-up picture of the wiring. Is that something someone can provide? I would really appreciate it. Please let me know. Thanks.