Finally made my breakout cable, and got the following results:
Pin Voltages Dir Name Comment 1 0.0v Out ENC_A Encoder A Output 2 0.0v Out ENC_B Encoder B Output 3 0.0v Gnd GND Ground 4 1.6v In CYM Ink Control 5 0.0v / 0.9v / 1.1v ? CYM Ink Control 6 0.0v Gnd GND Ground 7 0.0v / 1.5v ? Disconnect - No effect 8 0.0v / 1.5v ? Disconnect - Immediate stop of printing 9 0.0v Gnd GND Ground 10 1.6v In Black Ink Control 11 1.1v / 0.9v / 0.0v Out Black Ink Control 12 0.0v Gnd GND Ground 13 0.0v Disconnect - print continues, no ink output 14 0.0v Disconnect - immediate stop of print, E - Ink 15 3.3v Vcc VCC 3.3v for logic 16 0.0v ? Disconnect - immediate stop of print, no error 17 16v In VINK Voltage for ink jet 18 16v In VINK Voltage for ink jets 19 16v In VINK Voltage for ink jets 20 16v In VINK Voltage for ink jets
So, interestingly, looks like all the CYM ink control is on just one shift register.
Next, need to set up some LEDs to see if I can figure out which signals are used when, until I can get a good logic analyzer attached.
For now, investigation will focus on pins 4,5 and 10,11.
Hopefully the LED test will reveal which of the other pins is the ink shift register clock.