No diode effect measured. Resistance between each of the 6 pairs of "probes" is 100K ohms. This, of course, is the measurement of the parallel SMD resistor.
Note, there is only one sense conductor per color, and one Vcc (or Gnd -- haven't delved into the assembled and powered printer to determine this).
So, heaters are out of the question.
Would a centimeter of ink be in the neighborhood of 100K ohms? This, in parallel with the SMD resistor, would create a 2:1 change in the voltage across them when ink flows in the tube.
Just measured tap water, submerging DMM probe tips in a beaker: 300K ohms across ~0.75 inch (~2 cm). (Don't have any ink lying around to measure.)
I'm tempted to just add 50K ohm resistors parallel to the probe connections and see what happens.
Ideas?
Thanks.