Thanks for the info, everyone - very much appreciated.
The schematic I found for the Siel uses a 6116 which is only 16k and requires a battery to hold memory. Let me know if that's the wrong schematic.
Regarding Phil's post, what value of capacitor is required for decoupling? And, would it be as simple as a straight 1:1 wiring with the resistors and capacitor between the PCB and 6264?