I am currently building a counter ic clock. On the minutes display the decoder displays numbers 1,2,3,0,1,2,3,8,9,0 in that order repeatedly. I'm certain that all the chip is working by replacing it with a new one. Any help will be appreciated.

 

You should check your wiring and attach the circuit.

 

You are missing the 3rd input bit (pin 2 on the 4511)

 

thank you so much! looks like i shorted q3 to ground by accident. thank you very much.