This circuit makes use of a specific 80's component and was found in an American manual of the time. A matrix keyboard allows you to select one of several music programs.
January 2017 - Omron G7L-x relays for PCB mounting can now be purchased from Mouser Electronics. These...
General Electric suggests this circuit in an 80's documentation. The circuit makes use of PUTs...
This circuit uses a 4020 counter that divides the frequency up to 210, being found in a former...