There is one digital component in a '77 MGB

... and I found it.  No, not the amplifier for the solid-state CEI ignition module - that came out in '78.  This is a divider IC (serial number not readable) which counts down to divide a crystal oscillator to 1pps for the second hand in the clock in the dash.  The clock had stopped working, and a known repair technique is to replace the aged capacitors which leak dielectric over time.  It does involve prying apart the clock front bezel rim from the back case.  But 8 months later, still ticking with the repair job.  A replacement clock that fits the dash style (getting) rare, is $150.  So, good coding and hardware question - if the crystal oscillator is 4Mhz, how do you get down to 1 pps? How many dividers before you realize this is pretty easy to do on a Raspberry Pi 2 with Win 10 IOT?