I'm using the CD40175 for switching logic. All 4 inputs, d1 thru d4 will be used. There will be 2 CD40175 used, one main, one remote, and the D1 thru D4 inputs will be tied together via cable. Each chip's input will be tied to Vcc separately. The path is Vcc, 10K resistor, momentary switch, to input. Each input is connected to pin 9 - CLK thru a switching diode. and summed at pin 9. This way either the main, or remote can switch the outputs of each chip concurrently. The main CD40175 has a 15K shunt resistor to ground at each input, because we thought all unused inputs need to be grounded. However if the remote has the shunt resistors, the parallel combination of of the 15K shunts loaded the inputs down, and would not work. Removing the shunts at the remote solved the problem.
The question is, do I even need these shunt resistors at all, looking at long term reliable switching? It works just fine without them.
