I've modified one to act as a double switch for Kronos and my DX7s.
What I wanted was a pedal to compliment my Korg Sustain pedal (used on Kronos). Ideally, a pedal that could act as sustain on my DX7 (which is running as a MIDI master for additional channels in Kronos under Combi mode) and an assignable foot switch.
The awkward bit is that the DX7 requires a CLOSED switch for sustain (ie the circuit is closed until you press the switch, thus opening the circuit, creating sustain).
This was fun - I ended up using an electrical switch - the kind used as emergency stop buttons in workshops!!

To fix it to the case, I've used superglue (might up rate this "no more nails").
So the sustain works!

The additional footswitch cool too.
The ORIGINAL cabling is based around a balanced cable (ie Tip Ring Sleeve 1/4" connection - 3 connections: +ve, -ve & earth)
As it stands, I've cut the connector off, and re-soldered an unbalanced/mono connector and used +ve and 1/2 of the earth cable for the sustain.
The -ve and the remaining earth have been re-spliced into a 1/4" socket (unbalanced) and feed the other switch.
Currently, the configuration is -
Sustain - DX7s (midi controlling Kronos)
Footswitch - connected to "Switch" and controlling SW1 (from the Global page)
Works FANTASTICALLY!!!.
Pics to follow.
Dan
