[Mark1960]

My sketch schematic has the wrong values, I used 470pf and a 10k multiturn preset.

Minimum resistor that seemed to fix the corruption was 180ohm and didn’t seem to have an upper limit, maybe 220 would be a good choice. It did seem to drift slightly after running for a while and needed a slight adjustment.

47pF might work with preset adjusted to 1.8k.

I was using 4MHz crystal on the MK14 but can easily swap to 4.43316 to see if that affects the delay required.

Second half of the 74hct74 was just to buffer the RC delay instead of adding an extra chip.

Maybe let me experiment with the white band before you release a new layout. I’m wondering if a 74hct74 clocked by the serial clock of the PIC would work. Then one 74hct74 chip could fix two issues if the spare 74hct02 gate were used to buffer the RC delay.