Quoted from Ilikewires:If you see a flaw on the logic, please say something.
Just having a quick look comparing schematics against the original (sorry if actual factory board uses what you've spec'd).
* You're missing an inverter between the output of the zero crossing detector and the CTC chip.
* Your C11 on the input of the zero crossing detector is 0.1uF. Original is 0.001uF
I've seen some problems with timing of HC/HCT chips, do you just for test purposes have LS chips to try particularly U2, U27, U29?
Have you written any Z80 test code to try help determine why the Z80CTC isn't generating interrupts?