If the totalizer runs OK you should have input pulses getting through to the counter chain.
Have you checked S160 which selects internal / external clocks? If external is selected that could explain both the frequency and period oddities.
If S160 is OK then follow the time gating signal from U160 -> U180A -> U217A etc through to U220C where the gate pulse is combined with the signal pulses.
Likely failures are 74xx logic ICs and segments of the cam switch S200.
Regards,
Roger
