Although it is possible to bugger it up real good, note that the Morley uses a photocell/shutter arrangement, which means that it is possible to modify the taper of the sweep by altering the physical properties of the shutter.
My own experience is that sometimes the bulb, photocell, and shutter can get jostled, and small nudges of the photocell, in particular, can detract from the sweep. Where Vactrols seal the light source and photocell inside a common chassis, the Morley arrangement physically separates them to make room for the shutter.
My own experience is that sometimes the bulb, photocell, and shutter can get jostled, and small nudges of the photocell, in particular, can detract from the sweep. Where Vactrols seal the light source and photocell inside a common chassis, the Morley arrangement physically separates them to make room for the shutter.