74HC devices are relatively high speed logic and likely don't work well on a high stray-capacitance plug-in breadboard with such a rat's nest of long leads. To me it's not surprising that it doesn't work properly.
You might try using the slower CD4000 (CD4040 and CD4008) series devices and see if that helps.
But you likely need a cleaner layout with minimum length leads.
Even that can be problematic using a plug in type breadboard with its high stray capacitances.
You might try using the slower CD4000 (CD4040 and CD4008) series devices and see if that helps.
But you likely need a cleaner layout with minimum length leads.
Even that can be problematic using a plug in type breadboard with its high stray capacitances.