What is the make and model of the clock? I attended NYC public schools in the 1960s and we had Simplex clocks with master and slaves. They could do top of the hour correction if given a signal by the master. The procedure involved a third wire for some slaves and a long sync signal for others.

It would be a real pain in a large master clock system the slaves had to be manually set for DST or blackouts—not to say that couldn’t be the case, thpugh.

The clock system was made by Thomas Mercer Ltd in St Albans UK and was used in-house only as far as I’m aware. As they were a precision gauge manufacturer and also well know for their navigational chronometers, I’m guessing that the master clock was clockwork driven and quite possibly the pulse activation mechanical also. I do recall a member of staff having to go throughout the buildings with what looked like a small battery pack, in order to reset the time for DLS twice a year at each slave location. This was in the early 1970’s.

 

The 4060 is a 14-stage binary counter so it divides the input (or oscillator) frequency by a factor of 2^14 or 16,384, thus the 32,768Hz common watch crystal will give an output of 2 pulses/sec.
This is then further divided by 60 using the 40103 to give the desired 2 pulses/min.

Thanks for your reply, I should have been more precise in my comment. I understand how to achieve the 2Hz from the 4060 but having just found out about the 40103, it is with that IC that I’ve not yet understood how to divide by 60.

 

hi OK,
This link may help you figure it out.
E
https://microcontrollerslab.com/cd40103-cd40102-8-bit-synchronous-binary-down-counter/

 

Thanks for your reply, I should have been more precise in my comment. I understand how to achieve the 2Hz from the 4060 but having just found out about the 40103, it is with that IC that I’ve not yet understood how to divide by 60.

The 40103 can divide by any number up to 256. Its advantage is that the output pulse is always one clock period wide, regardless of the number it divided by.
Just place an 8 bit binary number equivalent to one less than the division ratio on the J inputs, by connecting them to the Vcc and Vss, and connect TC to PE.
The Nexperia datasheet has a good diagram on page 17.
https://assets.nexperia.com/documents/data-sheet/74HC40103.pdf
(The 74HC40103 is functionally identical, but only works of 2V to 6V power supplies)
[edit] I think is the same diagram as @ericgibbs posted above, but different manufacturers have different terms for the pins.

 

inexact: analogue=555 have a precision version allowing so long time as 30 sec
less inexact: 555 and signal divide digitally to 10 or to 64 etc
more exact, digital: - Pierce generator and frequency divider to two decades
Just about digital - qurtzed watch chip with shift register and second signal output
Absolutely exact, fully digital - Arduino with high precisity crystall and softwear-based frequency divider.