I picked up a partially functioning First Act MX530 on Reverb for about $15. The switch was openly non-functioning, and I figured it would be an easy fix to drill a new hole and drop in a replacement somewhere else on the case.

Well, I was wrong.

The switch was one of those plastic "pedal" style flapper momentary switches. Six pins, but the board was using them redundantly, so really only three active pins/positions. The solder joints looked cold, so I tried reflowing, which didn't do anything, so I pulled the switch to test and replace it.

Using my multimeter, I figured out that the switch was some sort of "double" momentary (I'm not sure what to call this - apologies). See the following:

[a] [b] [c]

[d] [e] [f]

Pins a, b, and c are redundant. Pins d and f are NC and open when the switch is depressed (and close again when it is released). Pins e and f are NO and close when the switch is depressed (and open again when it is released).

I tried for about an hour to figure out how to wire up another switch to it, but nothing worked. The original switch (despite seeming to function when I tested it with my meter) did nothing when installed on the board. In the end, the only thing that works reliably is touching a piece of metal (I used a copper alligator clip) to pin e to turn the pedal on, and unplugging one of the jacks to cut the power and turn it off.

I'm thinking this pedal uses some sort of digital switching circuit, but otherwise I'm stumped.

Any ideas?