Whammy 4 not reaching octave - Fixed

[stallik]

Couldn't find reference to this issue among these pages so I thought I'd post about it

Friend dropped off his son's Whammy 4 with me last night stating that the treadle couldn't reach the full octave even after multiple calibrations. I confirmed this myself by trying multiple times as I'd heard that it can sometimes take 4-5 calibrations before it 'takes'

Inside I found there was some dust on the graduated acrylic plate between LED & LDR which I figured might be altering the graduation so cleaned it off with a microfibre cloth.

The 'LDR' is actually a radial sidelooker LPT80A which is actually a phototransistor (Q2). It has a moulded plastic 'lens' on one side and, from what I could tell, small angle adjustements of this component in the light beam resulted in quite a change to it's sensitivity. So I moved it. Just a tiny bit. This moved the position of the top and bottom lit led's during calibration.

I went round this loop several times till I found a setting which would calibrate every time. conveniently,this was anywhere the top and bottom led's remained within the 'Whammy' section on the faceplate.

I postulate that the calibration routine within the firmware will only run correctly between a narrow range of voltages. Anything beyond that gets clipped somehow leaving you without the full treadle range. The pics of the board are taken before I messed with it and the jaunty angle of the LED is how I recieved it (straightening it did not effect a cure) though missing washers from all the top plate screws point to it having being opened before. The pedal was second hand so goodness knows it's history

Pedal now working correctly, Neighbours tired of my Whammy antics, not sure if I'd ever buy one. Mind you, the harmonies were pretty lush