Did you build this from a kit or was it built by us, at ZDL? What is your serial number?
Just to be clear, you are saying that the pedal works fine, when it is either bypassed or engaged, but when it is engaged the effect doesn’t seem to be working (there is no tremolo), just a louder guitar signal. Is this correct?
About the volume issue, set the volume knob in the center and adjust VR10 until the gain is set to unity.
-Brach