CD4029B: Binary counter irregular outputs

Hi Team,

Good day! Could you please help our customer? 

I have shared the full details of the inquiry below.

I am working with a CD4029BE on a breadboard. The connections are as follows:

VDD to +12VDC
VSS to ground
The clock input receives a 3Hz 0 to +12V clock pulse
J1-J4 are shorted together, to ground
Pin 5 (Carry in) to ground
Preset Enable shorted to ground
Up/Down and Binary/Decimal shorted to +12 to enable upward binary counting

The issue is that at the outputs, Q1-Q4, the outputs count correctly except that the pulse width randomly changes at all the outputs, meaning sometimes Q1 has a 50% duty cycle on/off, but every random number of pulses it will stay high or low for a bit longer than it should; the same behavior happens at the other outputs too.

I think this could be a stray capacitance issue, but the datasheet doesn't say anything about where bypass caps might be needed. If I add 0.1 or 0.001u ceramic caps near the power supply connections it affects the pulses at the outputs, but the outputs are still randomly wrong in the way described above.

I also tried a second 4029 IC that I had, and the same issue happens, but just with different random pulses wider or smaller on the outputs.

Please advise how I can stabilize the outputs of this IC.

Thank you in advance. 

Best regards,

Jonathan