The FM mod for Cocoquantus is done by adding five input screws, each wired to a ready-to-wire CV input pad on one of the quantussy oscillators.  I arranged the screws in an arc, following a photo I saw.  There is plenty of room, but be careful with placement to clear everything below deck.  The left-most screw on mine comes very close to the nearby input jack.  It’s a simple mod for anyone with soldering experience.  The new CV input is sensitive and sweeps the oscillator over a very wide range when patched directly to one of the triangle wave outputs.  Sometimes I patch in a potentiometer with alligator clips to attenuate the CV.

Detail of the new inputs

I could not find an exact match for the screws at two local hardware stores.  The originals must be #4 brass wood screws, 3/4″ in length.  The stores only had shorter #4s.  The 3/4″ length ones were #6, so that’s what I used.  I managed to fit #4 flat washers under them.

FM Mod Wiring

White wires run from the screws to pads surrounded by white squares.  The pads are easily identifiable, since these are the only ones inside a white square.  Two of these are visible in the photo.