clock with 4510 and 4511

Hi,

I have been trying to get a 1hz pulse for my clock and i have now succeded with doing this. (see https://www.electro-tech-online.com/threads/help-with-programming-a-pic-to-oscillate.42109/)
I have now got a 1hz pulse with the PIC.

When i connect the pulse to the 'clock in' on the 4510 and then to the 4511, but the displays just display random numbers every time i give power to it.

I cannot understand why this is not working.

any help would be gratefully recieved!

Thanks

Fred