Working on a replica of the ALF Products MC-16 card.
This is the original 1978 card, not the newer one with the programmable sound generator chip.
I'm having trouble finding a 1.782 Mhz crystal that drives the 8253 timer chip.
I could use a higher-frequency crystal, but would prefer not to.
The closest I've found so far is a 10.692 Mhz crystal from a surplus radio dealer (it's 6x the original frequency)
I could substitute something for the 4723 as long as it was functionally equivalent.