re that big capacitor
Hello Luke.
I seem to recall that same spring unit was sold by Maplin many years ago. As the thing hardly changes, perhaps there is still some info on using it. The English magazine Practical Electronics used the same unit, in many projects. The spring is quite short, this means the sound produced will not have a great deal of reverb. If you ever stumble on an old Hammond organ, some of them had a very long reverb unit which you might be able to salvage.
As for connecting the board, it is best to trace the circuit and draw it on paper - that way you end up with something to go on. Use a Ohm-meter to identify which pin connects directly to that big electrolytic capacitor on the right hand side *****- it looks like a power supply filter capacitor. On pin should connect to the positive lead, and on pin to the negative lead. If you manage to identify the two supply pins (positive and ground) you might find a working voltage printed on the side of the big filter capacitor, use that value, less 20%, as your supply voltage. Example: the capacitor reads 12V WKG (12 volts working limit) so you are safe to use a 9 volt supply.
That accounts for two of the pins, the other three could be either for a volume or 'tone'control, or maybe even a kind of 'reverb-presence control'.
Regards.
***** when I said right hand side, I meant from your perspective in the image, not the readers perspective.