/diy/ - Do It Yourself

>>1424614
>esp since I don't see a +5V supply source on the schematic anywhere
Yeah, the schematic isn't perfect. Someone mentioned that it was for a prototype of the pedal. There's a 7805.
I'm going to need some more help though. Honestly I don't understand how this optocoupler stuff works, nor the switching stuff. With the diode test function on my multimeter I'm getting 1.55V across both LEDs, which seems fine. When the pedal is on I'm measuring 4,998V at the anode of both LEDs, so that's obviously fine as well. But then I've got 3,5V at the cathode of D6, and 0 at D27?