Christopher wrote:
The schematic above matches that on the original OSI-300 trainer, with one exception. There was a small mixup with the resistor in the RC circuit that forms the clock. The resistor should be between pin 3 and pin 37. I found this when I assembled the prototype I had made.
I've replaced the schematic in that earlier post with your corrected version. Thank you, Christopher.
The OSI-300 replica board looks very nice... Bravo!
Cheerful regards, Mike